JPH01224630A - Long-sized thermopile and its manufacture - Google Patents

Abstract

PURPOSE:To measure temperature speedily by providing elements which have hot contacts adhered at one end of a base body and cold contacts at the other end adhered zigzag as thin wire type thermoelectric transducing elements made of different kinds of metal. CONSTITUTION:The thin and long base body 25 is used, the thin wire type thermoelectric transducing elements 23 and 24 made of different kinds of metal are adhered zigzag thereto, and a hot contact 21 is provided to one end of a thin and long member while a cold contact 22 is provided to the other end. Here, the base body 25 is a thin and long stripe type insulating or semiconductor substrate, and the elements 23 and 24 are adhered to the surface of this substrate. Further, an infrared-ray absorbing film 29 is adhered to the hot contact end part of the substrate 25 while covering plural hot contacts 21. Consequently, the number of contacts can be increased as compared with a stripe type base body, so the sensitivity of a long-sized thermopile is increased and the temperature is measured speedily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a long thermopile, an infrared thermometer using the same, and a method for manufacturing the long thermopile.

[Conventional technology]

Mercury thermometers are widely used as thermometers, but digital electronic thermometers are also becoming more popular recently.

Conventional electronic thermometers use a thermistor as a sensor and are often equipped with an arithmetic circuit for calculating temperature values and a digital display, but the time required to measure temperature is 2 to 3 minutes, which is worse than a mercury thermometer. To deal with this, a method has been developed that predicts the final value from the progress of temperature rise during the first minute or so, but with electronic thermometers that use a prediction method, the measured value does not necessarily match the actual value. The problem is that it doesn't.

Another factor related to temperature measurement time is the heat capacity of the sensor section. In a mercury thermometer, the mercury reservoir is warmed by body heat through a glass wall, and the expansion of the mercury is read, so the heat capacity of the heated object is quite large.

Electronic thermometers also use body temperature to warm the metal part that comes into contact with the measurement site, and the thermistor changes its resistance depending on the temperature of the metal part, so the heat capacity of the heated object (metal part) is large.

All of these thermometers are contact type, but there are also non-contact type thermometers, and JP-A-5L-88627R Non-Contact Oral Thermometer is an example. This uses a pyroelectric detection type infrared sensor to collect the infrared rays emitted from the oral cavity, chop it and input it to the sensor, amplify the sensor output, and calculate the body temperature based on the reference temperature signal. , displayed on the display. Alternatively, a thermistor is used as the infrared sensor, and the configuration includes a condensing system, a thermistor, an amplifier, an arithmetic unit, a display R groove, and a temperature detector.

There is also a system that measures body temperature by inserting it into the ear canal, and Japanese Patent Application Laid-Open No. 117422/1986 is one example. This uses a thermopile as an infrared sensor.

FIG. 5(a) shows its appearance, and FIG. 5(b) shows the electric circuit section,
(C) is a side view showing each part separated. In these figures, 10 is a thermopile, 11 is a thermistor, and 12° and 13 are resistors. These are embedded in the metal housing 14, and infrared rays are emitted from the tip of the temperature measuring cover 19 to the metal tube 1.
5 to the thermopile 10. Reference numeral 16 denotes a probe, which includes a hollow base 17 and a cylindrical portion 18 into which a metal tube 15 and a metal housing 14 are inserted.
A disposable cover 19 is fitted to the tip.

In this body temperature needle, the probe 16 is attached with the cover 19 attached.
is inserted into the ear canal, the thermopile 10 receives the infrared rays emitted by the ear canal through the above path, the output is input to a signal processing circuit (not shown) via the amplifier 20, and is converted into a body temperature signal and displayed on the display (not shown). let

Thermopiles, as is well known, produce an output that is a function of the temperature difference between hot and cold junctions, and have a shape such as that shown in FIG. 4, for example. In other words, the hot junctions are gathered in the center and arranged on the circumference,
The cold junctions are arranged on a concentric circle on the outside, and two types of thin dissimilar metal wires are alternately connected between the hot and cold junctions. It is miniaturized, and the distance between the hot junction group and the cold junction group is short. When measuring temperature, infrared rays emitted by the object to be measured are applied to the hot junction, and the cold junction is maintained at a constant temperature as much as possible.

If the temperature of the cold junction changes during temperature measurement, this will result in an error, so it is necessary to maintain the temperature before starting temperature measurement (reference temperature), but if the interval between the cold and hot junctions is short, infrared irradiation will cause an error. The increased temperature of the hot junction immediately reaches the cold junction and causes the temperature of the cold junction to rise, making it quite difficult to maintain the cold junction at the reference temperature. In FIG. 5, the housing 14 is heated by resistors 12 and 13, and the reference temperature is obtained by controlling with the thermistor 11, etc., but the configuration is complicated and it is difficult to expect a satisfactory result.゛Also, if the hot junction group and the cold junction group are close to each other, it is necessary to narrow down the infrared rays incident on the thermopile with an optical system so that it irradiates only the hot junction group, but optical systems such as lenses and reflectors is difficult to downsize.

[Problem to be solved by the invention]

In this way, conventional thermometers take time to measure temperature, whereas infrared thermometers that use thermopiles can measure temperature quickly, but require an optical system, are larger, and require a cold junction to set the reference temperature. There are problems such as it is not easy to maintain.

The purpose of the present invention is to improve these points, develop a thermopile with a structure suitable for miniaturization, and thereby provide a compact thermometer with a simple structure that can quickly measure temperature using infrared detection. It is something to do.

[Means to solve the problem]

As shown in FIG. 1, in the present invention, elongated substrates 25 to 27 are used, and thin wire thermoelectric conversion elements 23 made of different metals are attached to the elongated substrates 25 to 27.
．． 24 in a zigzag pattern so that the hot junction 21 is at one end of the elongated member and the cold junction 22 is at the other end.

In FIG. 1 (δ), the elongated base 25 is an insulating substrate or a semiconductor substrate in the form of a long strip, and the thermoelectric conversion elements 23, 24 are attached to the surface of this substrate. FIG. 1 (bl is a side view of this, and as shown in the figure, a thin wire thermoelectric conversion element 23
．． 24, the thickness of the hot junction 21 example is thin, and the thickness on the cold junction 22 side is thick. Further, a groove is provided in the lower part of the hot junction side of the substrate 25, and this groove is filled with a thermal insulator 28. Further, an infrared absorbing film 29 is applied to the end of the substrate 25 on the hot contact side so as to cover the plurality of hot contacts 21 .

In FIG. 1 (C1, the base body is a circular insulating tube body 26, and in FIG. 1(d), the base body is a square insulating tube body 27.
The thin wire thermoelectric conversion elements 23 and 24 are attached to the outer peripheral surfaces of these tubes. Although not shown, the hot junction sides of these tubes are also coated with an infrared absorbing film.

FIG. 2 shows an infrared thermometer using this long thermopile 10a. Reference numeral 30 denotes a cylindrical casing, the tip of which is tapered, and the long thermopile 10a is attached to the casing 30 with the hot junction side protruding from the tip. Reference numeral 32 denotes a signal processing circuit and a display section, which are also attached to the housing 30.

For example, a liquid crystal display for alphanumeric display is used as the display unit, and this displays 36.5° C. and the like so that it can be seen from the outside. 31 is a fin for cooling the cold junction, and 33 is a cap that covers the tapered tip of the housing 30.

The long thermopile shown in FIG. 1 can be manufactured by methods such as vapor deposition through a mask, full surface vapor deposition, and then etching (by photolithography).

In FIG. 3(a), two elongated insulating or semiconductor substrates 25a and 25b are used, and on the surface of the substrate 25a, one side 23 of a thin wire thermoelectric conversion element made of different metals and a plurality of contact portions 23a at one end thereof are formed. The substrate 25b is formed by the above method.
The other side of the wire-like thermoelectric element 24 made of different metals is
and a plurality of contact portions 24a at the other end are formed by the above method, and these are overlapped to form a thermopile. That is, when overlapped, one 2 is attached to the contact portion 24a at the other end of the other 24.
For example, one end of 3 contacts the contact portion 23a of the other 23 to form a hot junction, and the other end of the other 24 contacts the contact portion 23a of the other 23 to form a cold junction in this example, thereby forming a zigzag-shaped thermoelectric conversion element. A long thermopile is constructed by connecting a plurality of pairs in series. The superimposed substrates 25a and 25b are bonded together with an adhesive or the like to be integrated.

Further, if the base body is an insulating substrate, these integrated substrates may be processed to form a cylindrical substrate 26 and a rectangular cylindrical substrate 27, which may be bonded and integrated.

When processed in this way, the number of contact points of the thermoelectric conversion elements can be increased compared to the case of a strip-shaped substrate.
As described in the section ``Function'', it is possible to increase the sensitivity of the long thermopile accordingly.

[Effect]

When the thermopile shown in Fig. 1 is used as shown in Fig. 2, when the cap 33 is removed and the tip is inserted into the ear canal, the hot junction group receives the infrared rays emitted by the ear canal, and the cold junction group is maintained at room temperature. As a result, a temperature difference occurs at the cold/hot junction, and a thermoelectromotive force is generated. This thermoelectromotive force is proportional to the number of pairs of dissimilar metals, and increases as the logarithm increases (as the number of hot junctions increases). The combined thermoelectromotive force is guided from the cold junction side to the signal processing circuit through the lead wire, and its output (body temperature signal) is displayed on the display section.

As is clear from FIG. 1, in this thermopile loa, the hot/cold junctions are sufficiently far apart from each other, and by simply shielding them with the lead part of the casing 30, infrared rays irradiate only the hot junctions and cool them. It is possible to avoid irradiating anything else including the contacts, which makes it easier to maintain the cold junctions at a reference temperature (room temperature or a separately controlled temperature if necessary).

In addition, this thermopile has a thin thermoelectric conversion element on the hot junction side and a thick thermoelectric conversion element on the cold junction side (as a result, the heat capacity on the hot junction side is small, making rapid temperature measurement easy, and the electrical resistance Because of the thick thermoelectric element on the cold junction side, it does not become so large, which is effective in improving the S/N ratio and matching with the signal processing circuit.

By making a groove in the substrate 25 and filling it with a thermal insulator 28, the substrate on the hot junction side is thermally separated from the substrate on the cold junction side, which is effective in reducing the heat capacity of the hot junction 21 examples. .

Furthermore, by using tubes 26 and 27 as the substrates and attaching and forming thermoelectric conversion elements 23 and 24 on their peripheral surfaces, a large area can be obtained in a small space compared to the flat substrate 25, and a large number of cold/hot junctions can be formed. It is possible to easily provide a thermopile with high sensitivity and high output.

In the manufacturing method shown in FIG. 3(a), a thermopile can be manufactured by simply superimposing the substrates 25a and 25b on which one and the other of a pair of thermoelectric conversion elements are attached, thereby simplifying the process and speeding up the manufacturing process. In order to thicken the thermoelectric conversion element as shown in Figure 1 (bl), for example, vapor deposition is performed twice using a mask, the first time being applied to the entire surface, and the second time being applied to the hot junctions (so that the columns are not deposited). (by determining the mask pattern accordingly).

In addition, as shown in Figure 3 (bl), an existing thick (bulk) thermoelectric conversion element is used as the thermoelectric conversion element on the cold junction side, and the thermoelectric conversion element on the hot junction side is mounted separately by vapor deposition as described above. It is also possible to construct a desired thermopile using both.

Figure 1 (C) (Since vapor deposition and other processes are difficult for a tube like a dl, or a three-dimensional substrate, the thermopile is made in a flat plate shape and then rolled or bent into a tube shape. do it.

Instead of using the two substrates 25a and 25b, one substrate is used, and one of the thermoelectric conversion elements 23 and its terminal portion 23a are first deposited on this substrate by vapor deposition through a mask, and then vapor deposition is performed again through the mask. Then, the other thermoelectric conversion element 24 and its terminal portion 24a may be adhered to form a thermopile.

Of course, if the substrate is a highly flexible insulating substrate, such as polyethylene or polyimide, it may be rolled or bent into a tubular shape.

〔Example〕

As the thermoelectric conversion elements 23 and 24, antimony (Sb),
Metals such as indium (In) and bismuth (Bi), S
An i-doped layer or the like is suitable. The thickness of the thermoelectric element on the hot junction side is 1 μm or less, and the thickness on the cold junction side is 5 to 10 μm. The total length (distance between cold and hot junctions) is 30 m, of which the thin part is 1 (in) and the thick part is 2 (in).In this way, the internal resistance of the conventional product is about 100 ohms, compared to about 500 ohms. It can be:

Polyimide or the like is suitable for the thermal insulator 28. Silicon (Si), ceramic glass, or the like is used for the base 25 and the like, but if the base has good thermal insulation, it may be unnecessary to provide a groove and fill it with a thermal insulator for thermal insulation.

The cooling fins 31 may be used as electronic cooling elements to actively maintain a predetermined temperature through cooling control.

The infrared absorbing film 29 is made of goldfish, black body spray paint, or the like.

〔Effect of the invention〕

As explained above, the long thermopile of the present invention
It is easy to maintain a sufficient distance between the hot junctions, and it becomes easy to maintain the cold junctions at the reference temperature during temperature measurement. In addition, since the heat capacity of the hot junction can be reduced, temperature can be measured quickly.When used as a thermometer, an optical system is not required, and the viewing angle is large, so when used by inserting it into the ear canal, it can be used even if the insertion angle is uneven.゛Constant temperature measurement results can be obtained.

By performing ear canal temperature measurement with this configuration, it becomes possible to measure radiation temperature closer to a blackbody condition.

Moreover, if the base body is made into a tube, a large number of thermoelectric conversion element pairs can be accommodated in a small space, and high sensitivity and high output can be easily obtained.

It also makes it easier to insert into narrow places such as the ear canal.

Furthermore, the stacked manufacturing method shown in FIG. 3 is suitable for mass production and is effective in providing inexpensive thermometers.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the long thermopile of the present invention, Fig. 2 is an explanatory diagram of the infrared thermometer of the present invention, Fig. 3 is an explanatory diagram of the thermopile manufacturing method, and Fig. 4 is an explanatory diagram of the conventional thermopile. , FIG. 5 is an explanatory diagram of a conventional example of a thermometer. 1 to 3, 10a is a long thermomobile, 21 is a hot junction, 22 is a cold junction, 23.24 is a thermoelectric element, 25-
27 is a base, 28 is a thermal insulator, 29 is an infrared absorbing film, 3
0 is a tubular housing, 31 is a cooling fin, 32 is a signal processing circuit and a display section, and 25a. 25b is the first. The second substrates 23a and 24a are contact portions. Applicant Nippon Steel Corporation Representative Patent Attorney Minoru Aoyagi Figure 1 Figure 2 Thin harvested thermoelectric element made by vapor deposition Figure 3 10: Thermohile Figure 4! -Fn Procedural amendment (voluntary) June 15, 1988 Director General of the Patent Office Kunio Ogawa 1, Indication of the case Patent Application No. 50830 of 1988 2, Title of the invention Long thermomobile and its manufacturing method 3 , Relationship with the case of the person making the amendment Patent applicant address 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (6
65) Nippon Steel Corporation Representative Yutaka Sai 4, Agent 〒101 驋03 (8
63) 0220 Address No.-Higashi Building, 3-4-5 Iwamotocho, Chiyoda-ku, Tokyo Name (7017) Patent attorney
Minoru Aoyagi...-1-5°+m'E*'
n(7)8(t “ゝ 'e',,,:
”, , , , 6. Number of claims increased due to amendment
None -1111ぢ0DkZJ 8. Contents of amendment (1) "Thermistor" on page 3, line 13 of the specification is corrected to "thermistor or crystal oscillator." (2) Correct "insert" on page 4, line 19 to "insert". (3) On page 5, line 15, "(not shown)" is corrected to "(not shown)". (4) On page 6, line 3, "metal wire" is corrected to "metal wire."

Claims (1)

[Claims] 1. An elongated base, and a plurality of thin wire thermoelectric conversion elements made of different metals are attached to the base in a zigzag pattern, with a hot junction at one end and a cold junction at the other end of the base. A long thermopile characterized by comprising an element. 2. The long thermopile according to claim 1, wherein the thin wire thermoelectric conversion element is thin on the hot junction side and thick on the cold junction side. 3. Claims 1 to 2, characterized in that the plurality of hot junctions are covered with an infrared absorbing film, a groove is provided in the base near the cold junction side of the coating, and the groove is filled with a thermal insulator. A long thermopile according to any of the above. 4. Thin wire thermoelectric conversion elements are attached in a zigzag pattern to a cylindrical casing with a tapered tip, with multiple hot junctions formed at one end of the elongated base and multiple cold junctions formed at the other end. The hot junction of the long thermopile is mounted so as to protrude from the tip, and a signal processing circuit for the output of the long thermopile and a display section for displaying the temperature of the output of the signal processing circuit are attached to the cylindrical shape. An infrared thermometer characterized by being attached to a housing. 5. A first strip-shaped insulating substrate or a semiconductor substrate is coated with a plurality of one metal wire of a thin wire-shaped thermoelectric element made of different metals and a contact portion at one end thereof, and a second strip-shaped insulating substrate or The other metal wire and the contact portion at the other end of the thin wire thermoelectric conversion element made of different metals are adhered to the semiconductor substrate in the same number as the metal wires adhered to the first substrate, and these first and second strip-shaped The insulating substrate is placed in such a manner that one end of the other metal wire is in contact with the contact part of one end of the other metal wire, and the other end of one metal wire is in contact with the contact part of the other end of the other metal wire,
A method for manufacturing a long thermopile, comprising the step of overlapping them so that a zigzag-shaped thermoelectric conversion element pattern is formed. 6. A process of attaching a plurality of thin wire thermoelectric conversion elements made of different metals to a highly flexible insulating substrate in a zigzag pattern with a hot junction at one end and a cold junction at the other end, and forming the substrate into a cylindrical shape. Alternatively, a method for manufacturing a long thermopile, comprising the step of processing and adhering it into a rectangular tube shape.