JPH0511570B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Technical Field of the Invention>> This invention relates to a temperature-sensitive probe for an electronic thermometer;
In particular, it relates to a sheet-shaped thermosensor probe that is intended to be disposable after each measurement of body temperature.

<Summary of the Invention> The present invention includes a thermistor chip and conductive means for external connection contained between an insulating laminate film, and a conductive pattern is printed and formed on the bonding surface side of the film. The structure is such that electrical connection is made by pressing a thermistor chip onto this, and a part of the conductive pattern is trimmed together with the film to adjust the resistance, improving productivity and reducing costs. It has been made possible.

《Prior art and its problems》 This type of sheet-type temperature-sensitive probe was first introduced in 1976.
A representative example is Patent Application Publication No. 500191 (based on a PCT application), which has also been put into practical use. Regarding electronic thermometers that use sheet-type temperature-sensitive probes, for example, Patent Application Publication No. 54422 published in 1982
No. has been started.

In the conventional sheet-type temperature-sensitive probe described in the above publication, two metal wires are stretched in parallel between two insulating sheets, and the two electrode surfaces of the thermistor chip are soldered to both wires. , which is sandwiched between both sheets. Also, the tip end where the thermistor chip is installed is later covered with a plastic film to cover the cut surface of the wire to insulate it and make it liquid-tight. This allows the tip of the probe to be inserted into a person's mouth without any problems.
Further, a terminal window hole is formed on the proximal end side of the probe, and the wire is exposed within the hole. This exposed wire contacts the terminals of the electronic thermometer.

In the conventional structure described above, the two insulating sheets are further covered with a plastic film, so the number of parts is large and the assembly process is very troublesome. Furthermore, there are multiple steps for stretching and cutting wires on the sheet. Furthermore, soldering the wire and the thermistor chip is a very troublesome process because the chip is minute. In this respect, conventional products have extremely poor productivity, which is a major limiting factor in cost reduction through mass production.

In addition, in the conventional type, as a countermeasure against variations in the resistance value of the thermistor chips, two thermistor chips are connected in series between the wires.
The resistance values of the two chips are combined appropriately to ensure that the combined resistance value is uniform. This measure makes productivity even worse. In addition, a metal plate is used as an intermediate connector to connect chips in series, but this metal plate increases the heat capacity of the chips and the surrounding area, causing a longer time for body temperature measurement.

[Object of the Invention] This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide a simple structure with a small number of parts and to enable mass production of high-quality products at low cost. The object of the present invention is to provide a highly productive sheet-type temperature-sensitive probe.

<Structure and Effects of the Invention> Therefore, the present invention has a basic structure in which a thermistor chip is sandwiched between two insulating films and laminated together, and two conductive patterns are printed in advance on one or both bonding surfaces of the films. The two electrode surfaces of the thermistor chip were brought into pressure contact with the conductive pattern, and part of the conductive pattern was exposed in the terminal window hole formed in the film.

Further, in the present invention, part or all of the conductive pattern is formed of a material with relatively high resistivity, and a predetermined portion of the conductive pattern is trimmed together with the film in accordance with the resistance value of the mounted thermistor chip. .

The thermistor chip contained in the laminate film is electrically connected to a conductive pattern printed on the inner surface of the film, and is electrically connected to the conductive pattern in the terminal window hole.

Further, variations in the resistance value of the thermistor chip are compensated for by the above-mentioned trimming, and the resistance value seen from the terminal portion of the conductive pattern is made uniform.

In the sheet-type temperature-sensitive probe according to the present invention, a thermistor chip is sandwiched between two laminated films, and a conductive pattern printed on the inner surface of the film is used as wiring for external connection. It does not involve complicated processes such as wiring or soldering, so it can be mass-produced extremely easily, and its simple structure reduces the number of defective products.

Furthermore, since the conductive pattern is trimmed together with the film to adjust the overall resistance, the characteristics of the product can be made uniform through a very simple process.

<<Description of Embodiment>> FIGS. 1 and 2 show the structure of a sheet-type temperature-sensitive probe according to an embodiment of the present invention.

In FIG. 1 and FIG. 2, 20a, 20b
are two insulating films with the same external shape, and both films 20a and 20b are bonded (laminated) with their external shapes aligned, but conductive patterns 22a and 22b are preprinted on the bonding surfaces, respectively. ing. The conductive patterns 22a and 22b are
It is formed by, for example, silk printing using a conductive paste in which silver, carbon, etc. are dispersed in a suitable binder.

When the films 20a and 20b are pasted together,
The respective conductive patterns 22a and 2b are arranged in parallel at regular intervals.

A thin square thermistor chip 24 is sandwiched and fixed in the center of the circular portion at the tip of both films 20a, 20b. Thermistor chip 24
Conductive coatings are formed on both the front and back surfaces of the substrate, and the coatings serve as two electrode surfaces. The thermistor chip 24 has conductive patterns 22a, 22
It is positioned so that each side forms an angle of 45 degrees with respect to the longitudinal direction of b, and the corners of both the front and back surfaces are pressed against and electrically connected to the conductive patterns 22a and 22b.

It is preferable to use plastic films for the films 20a and 20b, and to bond the two films 20a and 20b by thermocompression bonding. If sufficient bonding strength cannot be obtained by thermocompression bonding, use both films 2.
0a and 20b may be bonded together using an adhesive (a heat-sensitive adhesive is applied in advance). Note that the film 20 is not limited to plastic film, and for example, paper material coated with plastic can be used as the film 20.
You may use it as a, 20b.

Before pasting the films 20a and 20b together,
There is a thermistor chip 24 on the inner side of one of the films.
At this time, the thermistor chip 24 may be fixed onto the film using an adhesive. Note that a square recess corresponding to the thermistor chip 24 is formed in one or both of the films 20a and 20b, and the chip 24 is inserted into the recess.
may be accommodated.

The rectangular portions on the base end side of the films 20a, 20b are terminal portions. In this part, film 2
A rectangular terminal window hole 26a is formed in 0a, and the conductive pattern 22b of the other film 20b is exposed within this window hole. Similarly, the conductive pattern 22a of the film 20a is exposed within the terminal window hole 26b formed in the film 20b. This exposed conductive pattern is a terminal for external connection, and by sandwiching this portion between the electronic thermometer, the present probe and the electronic thermometer are electrically connected.

The conductive patterns 22a and 22b are made of a material with relatively high resistivity. In other words, by adjusting the blending ratio of the good conductive material in the conductive paste for printing,
The pattern width, length, and coating thickness during printing are appropriately selected, and the total length of the conductive patterns 22a and 22b is
It has a resistance value of KΩ to several tens of KΩ.

A thermistor chip 24 is mounted on the conductive patterns 22a, 22b, and the films 20a, 20b are
After laminating the thermistor chip 24, the thermistor chip 24 is kept at a constant temperature (for example, 37°C), and the conductive pattern 22 is
An ohmmeter is connected to the terminal portions of a and 22b to measure the overall resistance, and a portion of the conductive patterns 22a and 22b is trimmed together with the films 20a and 20b so that the resistance value becomes a predetermined value.

Reference numeral 28 in FIG. 1 is the cut groove after the above-mentioned trimming. In this example, the conductive pattern 22
Two grooves 28 are formed perpendicularly to the base side of the conductive pattern 22a to narrow the effective width of the conductive pattern 22a, thereby increasing the resistance value of the conductive pattern 22a. By changing the length and spacing of these grooves 28, 28, the amount of increase in resistance value can be adjusted.
By this trimming adjustment, the thermistor chip 2
It is possible to compensate for the variation in the resistance value of No. 4 and to make the resistance value as seen from the terminal part constant. Note that this trimming is performed using a laser, a cutter, or the like.

By the way, it is not necessary to make the entirety of the conductive patterns 22a and 22b a high-resistance material, and only a portion thereof may be made a high-resistance material and that portion may be trimmed.

Next, an example of the manufacturing process of the above-mentioned sheet-type temperature-sensitive probe will be explained. First, as shown in Figure 3,
A strip-shaped film 50 of a predetermined width is prepared, and terminal window holes 52, 52, . . . are formed at a constant pitch along both sides of the film 50.
(The arrangement of holes 52 on both sides differs by half a pitch). Conductive patterns 54, 54, . . . are formed on one side of this film 50 by silk printing. In this example, the conductive patterns 54 are formed in parallel with left and right opposite directions, shifted by half a pitch.

Next, as shown in FIG.
A thermistor chip 56 is positioned and glued to the thin tip of the. At this time, thermistor chip 5
Each side of the conductive pattern 54 forms an angle of 45 degrees in the longitudinal direction of the conductive pattern 54, and the conductive pattern 54 is arranged so that the back surface of one corner thereof is in contact with the conductive pattern 54.

After bonding the thermistor chip 56, another film 50 having the same structure is placed on top of this film 50 with the printed surfaces of the conductive patterns 54 facing each other, and positioned. At this time, the conductive pattern 50 stacked on top becomes parallel to the conductive pattern 50 below at a constant distance, as shown by the two-dot chain line a, and its tip touches the top surface of the other corner of the thermistor chip 56. Place them so that they touch each other. Thereafter, the two stacked films 50, 50 are firmly joined by thermocompression bonding. Due to this film bonding force, the thermistor chip 56 and the conductive pattern 5
4 are securely electrically connected.

Then, when the laminate film is cut along the dotted line b in FIG. 4 and perforations 14 are formed, a large number of probes 10,
10, . . . are successively aligned and formed on the connecting pieces 12 to complete two pieces. individual probes 10,1
0, . . . can be easily separated from the connecting piece 12 by the perforations 14.

In addition, since each side of the thermistor chip 56 is inclined at 45 degrees with respect to the conductive pattern 54, the distance between the two conductive patterns connected to one chip 56 can be kept relatively large, and the two films 50, 50 can be attached. This makes it easy to determine the best position to match.

However, the above-mentioned trimming adjustment of the conductive pattern requires a large number of probes 10, 1 as shown in FIG.
This can be done in a continuous state of 0, . . . , and the workability is better that way.

In the above embodiment, a conductive pattern is printed on each of the two films to be laminated, but when placing the terminals of the two conductive patterns on one surface of the completed probe, Two conductive patterns are formed on the bonding surface of one film, and a terminal window hole is formed in the other film to expose a portion of the pattern.

[Brief explanation of the drawing]

FIG. 1 is an enlarged perspective view of a probe according to an embodiment of the present invention, FIG. 2 is a perspective view of the probe shown in FIG. 1 with part of the film removed, and FIG.
4 and 5 are plan views of the product in each manufacturing process of the same probe. 10... Probe, 20a, 20b, 50... Film, 22a, 22b, 54... Conductive pattern, 2
4, 56...Thermistor chip, 26a, 26b,
52...Terminal window hole.

Claims (1)

[Scope of Claims] 1. A sheet-type temperature-sensitive probe formed by laminating two insulating films, in which a thermistor chip is sandwiched and fixed at one end between the films, and the bonding surface of the films is fixed. Two conductive patterns are printed on the thermistor chip.
two electrode surfaces are in pressure contact with the conductive patterns, a terminal window hole is formed on the other end side of the film, the conductive pattern is exposed in the terminal window hole, and one of the conductive patterns A sheet characterized in that part or all of the sheet is made of a material with relatively high resistivity, and a predetermined part of the conductive pattern is trimmed together with the film in accordance with the resistance value of the thermistor mounted thereon. Shaped temperature probe.