JPH07183105A - Chip type thermistor - Google Patents

Abstract

(57) [Abstract] [Purpose] The shape of the glass layer and the baking electrode layer during the formation of the baking electrode layer is good, and the surface of the glass layer is smooth and looks good. It has excellent solder heat resistance and solder adhesion, and does not change its resistance value due to the plating process of the baked electrode layer, resulting in high reliability and high bending strength. [Structure] The chip type thermistor 10 is a thermistor element body 1.
1 and an insulating glass layer 14 covering the surface of the element body excluding both end surfaces of the element body, and a pair of terminal electrodes 12 provided at both ends including both end surfaces of the element body. The electrode 12 has a baked electrode layer 16 formed on both ends of the element body and plated layers 18 and 19 formed on the surface of the electrode layer. A part or all of the glass layer 14 is composed of a lower glass layer 14a of crystallized glass formed on the surface of the element body and an upper glass layer 14b of amorphous glass having a hermeticity formed on the lower glass layer. To be done. The glass transition point of the precursor glass of crystallized glass is 400 to 10
In the range of 00 ° C, the crystallization temperature is higher than the glass transition point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type thermistor suitable for a temperature compensating thermistor and a surface temperature measuring sensor for various electronic devices. More specifically, it relates to a chip type thermistor surface-mounted on a printed circuit board or the like.

[0002]

2. Description of the Related Art Conventionally, this type of chip type thermistor is
Electrodes containing silver-palladium as a main component are baked on both ends of the thermistor element to improve solder heat resistance, and a plating layer is provided on the surface of the baked electrode to enhance solder adhesion. In order to prevent the resistance from changing due to the adhesion of the plating to the surface of the thermistor element body having conductivity during this plating treatment, the applicant of the present invention has a softening point on the surface of the thermistor element other than the part where the baking electrode layer contacts. A patent application has been filed for a chip type thermistor which is covered with a glass layer having a temperature substantially equal to the baking temperature of the layer and has a plating layer formed on the surface of the baking electrode layer (JP-A-3-250603). Further, the present applicant has a glass layer with glass, alumina, zirconia, so that the glass layer does not soften during baking of the electrode layer after forming the glass layer.
A patent application was filed for a thermistor composed of an inorganic composite material containing an inorganic crystal such as magnesia (JP-A-3-25060).
4).

[0003]

However, Japanese Unexamined Patent Publication No. 3-2.
In the thermistor disclosed in Japanese Patent No. 50604, it is difficult to uniformly mix the glass powder and the inorganic crystal powder in the paste for forming the glass layer. Therefore, this paste has poor printability and the surface of the thermistor body after printing. There was a problem that was not smooth. In addition, bubbles are likely to remain in the inorganic composite material due to the presence of the inorganic crystalline material during firing of the inorganic composite material. The remaining bubbles are apt to become open pores, and the plating solution penetrates into the open pores during the subsequent plating process and corrodes the thermistor body with the plating solution, which reduces the reliability of the thermistor. there were. Furthermore, after the electrode layer is baked, the surface of the glass layer becomes rough, impairing the appearance of the thermistor, and when used in a hot and humid environment, the resistance value changes depending on the degree of open pores, reducing the reliability of the product. was there.

An object of the present invention is to provide a chip type thermistor which has good shape retention of the glass layer and the baking electrode layer when forming the baking electrode layer. Another object of the present invention is to provide a chip type thermistor in which the surface of the glass layer is smooth and has a good appearance. Another object of the present invention is excellent in solder heat resistance and solder adhesion, there is no change in the resistance value due to the plating treatment of the baking electrode layer, and there is no change in the resistance value even in an environment such as high temperature and high humidity, which is reliable. It is to provide a chip type thermistor having high performance. Still another object of the present invention is to provide a chip type thermistor having high strength against tensile stress caused by thermal stress.

[0005]

As shown in FIGS. 1 and 2, a chip type thermistor 10 of the present invention covers the thermistor element body 11 and the surface of the element body excluding both end surfaces of the thermistor element body 11. And a pair of terminal electrodes 12 and 12 provided at both end portions of the thermistor element body 11 including both end surfaces thereof.
2 is a baked electrode layer 16 formed on both ends of the thermistor body 11 and N formed on the surface of the baked electrode layer 16.
This is an improvement of the thermistor having the i plating layer 18 and the Sn or Sn / Pb plating layer 19, respectively. The characteristic structure is that a part or all of the glass layer 14 is a lower glass layer 14a made of crystallized glass formed on the surface of the element body, and a closed amorphous layer formed on the lower glass layer 14a. And an upper glass layer 14b made of high quality glass,
The glass transition point of the precursor glass of this crystallized glass is 40.
It is in the range of 0 to 1000 ° C. and the crystallization temperature is higher than the glass transition point. here,
The "precursor glass of crystallized glass" refers to glass before heat treatment for crystallizing crystallized glass.

In addition to those shown in FIGS. 1 and 2, the chip type thermistor of the present invention has terminal electrodes 12 formed on the surface of the thermistor element body 11 other than both end surfaces as shown in FIG. 4 or 5. , 12 having a resistance adjusting internal electrode 21 electrically connected thereto, and the glass layer 14 is configured to cover the surface of the element body other than both end surfaces including the internal electrode 21, and a part of the glass layer 14 Alternatively, the lower glass layer 14a made of crystallized glass is formed entirely on the surface of the element body, and the upper glass layer 14b made of amorphous glass having a hermeticity is formed on the lower glass layer 14a. Including a chip type thermistor 20.

The chip type thermistor of the present invention is shown in FIG.
Alternatively, as shown in FIG. 8, on the surface of the thermistor element body 11 other than both end surfaces thereof, internal electrodes 22 for resistance value adjustment that are not electrically connected to these terminal electrodes 12, 12 are provided, and the glass layer 1
4 is configured to cover the surface of the element body other than both end surfaces including the internal electrode 22, and a part or all of the glass layer 14 is a lower glass layer 14a made of crystallized glass and formed on the surface of the element body. The chip type thermistor 30 is configured by an upper glass layer 14b made of amorphous glass having a hermeticity and formed on the lower glass layer 14a.

The chip type thermistor of the present invention is shown in FIG.
As shown in FIG. 5, the thermistor body 11 has a resistance value adjusting internal electrode 23 electrically connected to the pair of terminal electrodes 12 inside the body, and the glass layer 14 covers the surface of the body other than both end surfaces. And a lower glass layer 14a made of crystallized glass in which a part or the whole of the glass layer 14 is formed on the surface of the element body and a non-sealing non-sealing layer formed on the lower glass layer 14a. Upper glass layer 1 made of crystalline glass
4b and a chip type thermistor 40. Although not shown, a chip type thermistor in which the internal electrode 23 is not electrically connected to the pair of terminal electrodes 12, 12 is also included.

The chip type thermistor 10 shown in FIGS. 1 and 2 is manufactured by the following method. As shown in FIG. 3, first, a ceramic sintered sheet 11 for a thermistor element body
((A) in the figure) is prepared. This sintered sheet 11 is M
After mixing one or more kinds of oxide powders of metals such as n, Fe, Co, Ni, Cu and Al, calcining and crushing the mixture, adding an organic binder and mixing to form a rectangular parallelepiped , A ceramic sintered block (not shown) is formed by firing,
Then, this block is cut into a wafer using a band saw. After calcination and pulverization of the mixture of metal oxides, an organic binder and a solvent were added and kneaded to prepare a slurry, and the slurry was film-dried by a doctor blade method or the like to form a green sheet. May be fired to form the sintered sheet 11.

A glass layer 14 is formed on both sides of the sintered sheet 11.
To form. First the first glass paste is printed and dried, then the second glass paste is printed and dried,
By firing, a lower glass layer 14a made of insulative crystallized glass and an upper glass layer 14b made of an insulative amorphous glass having a hermeticity are formed (FIG. 2B). Next, the sintered sheet 11 having both surfaces covered with the glass layer 14 is cut into strips using a dicing saw such as a cutter with a diamond blade (FIG. 2C), and then the strip-shaped thermistor body 13 The same first and second glass pastes as described above are sequentially printed on the cut surfaces on both sides, dried, and then fired to form a glass layer 14 composed of a lower glass layer 14a and an upper glass layer 14b (FIG. 3 (d)). ). Next, the strip-shaped thermistor element body 13 is finely cut in a direction perpendicular to the cut surface to make a chip 15 (FIG. 8E). A conductive paste containing a noble metal powder and an inorganic binder is applied to both ends of the chip so as to wrap the cut surface of the chip 15 and fired to form an electrode layer. Further, the baked electrode layer is used as a base electrode layer to form a plating layer on the surface thereof, and a terminal electrode 1 including the baked electrode layer and the plated layer is formed.
A chip type thermistor 10 having 2 is obtained ((f) in the same figure).

The chip type thermistor 20 shown in FIG.
It is manufactured by the following method. As shown in FIG. 6, first, a conductive paste containing a noble metal powder and an inorganic binder is printed on both surfaces of a ceramic sintered sheet 11 produced in the same manner as described above at intervals with a belt-like pattern and dried to form a large number of rows. The internal electrode 21 for adjusting the resistance value is formed ((a) in the same figure). Next, the glass layers 14 are formed on both sides of the sheet 11. Figure 3 (b)
In the same manner as above, the glass layer 14 including the lower glass layer 14a and the upper glass layer 14b is formed ((b) of the same figure). Next, the sintered sheet 11 whose both surfaces are covered with the glass layer 14 is attached to the electrode 2
After being cut in a strip shape in a direction orthogonal to the column direction of 1 (FIG. 1 (c)), the same first and second glass pastes as described above are sequentially printed on the cut surfaces on both sides of this strip thermistor element body 13. Then, it is dried and then fired to form a glass layer 14 composed of a lower glass layer 14a and an upper glass layer 14b (FIG. 2 (d)). Next, in the direction perpendicular to the cut surface and in the electrode 21
This strip-shaped thermistor body 1 along the center line in the width direction of
3 is finely cut to make a chip 15 ((e) in the same figure).
A conductive paste is applied to both ends of the chip so as to wrap the cut surface of the chip 15, and is baked to form an electrode layer.
Further, by using this baked electrode layer as a base electrode layer, a plating layer is formed on the surface of the baked electrode layer to obtain a chip type thermistor 20 having a terminal electrode 12 composed of the baked electrode layer and the plated layer (FIG. 6 (f)).

The chip type thermistor 20 shown in FIG.
6A, except that the resistance-adjusting internal electrodes 21 are alternately formed on each of the upper and lower surfaces one by one, and are manufactured in the same manner as in FIG. The chip-type thermistor 30 shown in FIG. 7 or FIG. 8 is made by cutting the electrode 21 of the strip-shaped thermistor element body 13 in FIG. Are formed in the same manner as in FIG. The chip type thermistor 40 shown in FIG. 9 is manufactured by the following method. First, a ceramic green sheet for a thermistor body is formed extremely thinly, a conductive paste is printed on the upper surface of the sheet and dried to form an internal electrode 23, and then a plurality of green sheets are stacked to form a sheet-shaped laminated body. The sintered body is fired to make a sintered sheet. After that, the chip type thermistor 40 is obtained by the same method as shown in FIGS.

The glass layer 14 described above will be described in detail. A part or all of this glass layer is composed of two layers, a lower glass layer and an upper glass layer. The lower glass layer is made of crystallized glass formed on the ceramic body, and the upper glass layer is made of amorphous glass having a hermeticity formed on the lower glass layer. The lower glass layer is printed or coated with a glass paste described below, dried, and then fired to form 5
It is formed to have a thickness of about 20 μm. When the lower glass layer is partially crystallized glass, the crystallization rate is required to be 10% or more in order to achieve the object of the present invention. Here, the crystallized glass is a glass-ceramic produced by a method in which a uniform amorphous glass is fired in the vicinity of its softening point according to a controlled schedule to convert it into fine crystal clusters. In order to obtain crystallized glass, amorphous glass powder (raw glass powder) contained in the glass paste is selected and blended so that it can be crystallized, and the glass contained in the glass paste is crystallized. It is necessary to bake the dried paste so as to be solidified under a predetermined temperature condition.

The precursor glass of the crystallized glass has a glass transition point in the range of 400 to 1000 ° C. and a crystallization temperature of the glass so that the density of the lower glass layer after firing the glass paste is good. It must be higher than the transition point. The range of the glass transition point is determined in consideration of the firing temperature of the electrode layer. When Ag is used for this electrode layer, the firing temperature is 600 to 850 ° C., and when the glass transition point is significantly lower than that temperature, for example, when the glass transition point of the precursor glass of crystallized glass is less than 400 ° C. May have a crystallization temperature of lower than 600 ° C., and the crystallized glass may be deteriorated during firing of the electrode layer. Further, when the glass transition point of the precursor glass exceeds 1000 ° C., the crystallization temperature becomes higher than 1000 ° C. and the thermistor element may be deteriorated.

On the other hand, the upper glass layer must be selected and blended so that the amorphous glass powder (raw glass powder) contained in the glass paste does not crystallize under the above-mentioned firing conditions of the lower glass layer. Is. The upper glass layer is formed to have a thickness of about 5 to 20 μm by printing or applying a glass paste containing such raw material glass powder, drying it, and then firing it. In order to achieve the object of the present invention, the crystallization rate of the lower glass layer is 10% or less and it is necessary to seal the lower glass layer.

The coefficient of thermal expansion of the crystallized glass of the lower glass layer is 40% or more and 100% of the coefficient of thermal expansion of the thermistor body.
It is preferably not more than 50%, more preferably not less than 50% and not more than 90%. When it is 40 to 100%, the bending strength of the chip type thermistor is increased as compared with the case where the glass layer is not provided, and the glass layer is made of uncrystallized glass and the coefficient of thermal expansion is the above. It also increases compared to what is in range. In particular, when it is 50 to 90%, the bending strength is increased by 20 to 70%, respectively, as compared with the case where the glass layer is not provided and the case where the glass layer is made of uncrystallized glass. On the other hand, outside the range of 40 to 100%, the flexural strength is reduced as compared with the case where the glass layer is not provided and the case where the glass layer is made of uncrystallized glass.

The transverse rupture strength means that two pieces are arranged at intervals.
It is the breaking strength when both ends of the chip type thermistor are placed on one table and a load is applied to the center of the chip type thermistor. This is due to the stress (mechanical stress) caused by the mounting machine when the chip-type thermistor is surface-mounted on the printed circuit board, or the stress strain (thermal stress) caused by the heat from solder or the thermal cycle after mounting. It will be a measure of how long you can endure.

It is considered that the bending strength of the chip-type thermistor of the present invention is increased because compressive stress remains in the glass layer on the surface of the thermistor body. That is, when the thermistor element body and the glass layer that have been thermally expanded at the time of firing the glass are cooled, the thermistor element body having a large coefficient of thermal expansion shrinks more and the glass layer is in a compressed state. When a bending force is applied to the chip type thermistor in this state, a compressive stress is generated inside the bending and a tensile stress is generated outside. Both the thermistor element body and the glass layer are characterized by high compressive stress and weak tensile stress. For this reason, when a large compressive stress is applied to the glass layer in advance, compared to the glass layer not provided and the glass layer made of uncrystallized glass, when the bending force is applied to the outside of the bend. Cracks are less likely to occur in response to tensile stress. Like the crystallized glass of the lower glass layer, the amorphous glass of the upper glass layer also has a thermal expansion coefficient of 40% or more 100% or more of the thermal expansion coefficient of the thermistor body.
% Or less, particularly preferably 50% or more and 90% or less.

[0019]

As shown in FIG. 2, the surface of the thermistor element body 11 excluding both end surfaces is covered with a lower glass layer 14a and an upper glass layer 14.
By coating the insulating glass layer 14 of two layers consisting of b, the baking electrode layers 16 on both ends of the thermistor element body 11 including both end surfaces, and then providing the plating layers 18 and 19, the chip type thermistor 10 is formed. Is made. The lower glass layer 14a of the glass layer 14 is a crystallized glass, and since the glass paste to be the crystallized glass does not contain an inorganic crystal substance as in the conventional case, the printability is good and the lower glass layer is formed. Since the glass sometimes reaches the crystallization temperature through the glass transition point, the compactness of the glass itself after firing is good.

The upper glass layer 14 of the glass layers 14
Since b is an amorphous glass and seals the lower glass layer 14a, even if there are fine open pores in the lower glass layer 14a, these open pores are covered and the surface of the glass layer 14 is smoothed. To do. Therefore, the thermistor body 11 is completely covered and only the electrode layer 16 is plated. The two glass layers prevent erosion of the plating solution on the thermistor element body 11 and adhesion of the plating to the element body 11 during the plating process, and the resistance value of the thermistor does not fluctuate with respect to the desired value. Ni
The soldering heat resistance is improved by the plating layer 18, and when the thermistor is soldered to the substrate, the electrode layer 16 made of solder is used.
Prevents electrode erosion. Further, the Sn or Sn / Pb plating layer 19 improves the solder adhesion of the terminal electrode 12. Since the plating layers 18 and 19 cover the surface of the noble metal baking electrode layer 16, the noble metal ion migration is unlikely to occur. In addition, since the lower glass layer 14a is a crystallized glass, the viscosity of the glass itself does not decrease during the formation of the electrode layer 16, and the glass layer at the edge portion of the thermistor element and the baked electrode layer 16 at the edge portion disappear. No trace of fusion or contact with the firing jig or the like remains on the glass layer 14 after the electrode layer is formed.

Further, if the coefficient of thermal expansion of the crystallized glass is made appropriately smaller than the coefficient of thermal expansion of the thermistor element body, a large compressive stress is given to the glass layer of the produced chip type thermistor, and the chip type without the glass layer is provided. As compared with a thermistor or a chip type thermistor having only a glass layer of uncrystallized glass, when a bending force is applied, cracks are less likely to occur due to tensile stress outside the bend.

[0022]

As described above, according to the present invention, the lower glass layer of the glass layer is made of crystallized glass, so that the glass layer is softened and deformed during firing electrode layer formation, or is cured by firing. Since it does not fuse to a tool or the like and the electrode layer does not melt into the glass layer, the glass layer and the baked electrode layer have good shape retention. Further, by forming the upper glass layer made of amorphous glass on the lower glass layer and closing the open pores of the crystallized glass, the surface of the glass layer is smooth and the thermistor looks good. Further, since the thermistor element body is completely protected by the double-structured glass layer, the resistance value of the thermistor does not change due to the erosion of the plating solution during the plating treatment after forming the electrode layer. Secondly, the resistance value does not change under the environment of high temperature and high humidity after mounting the thermistor. As a result, a highly reliable chip type thermistor having plating solution resistance and weather resistance can be obtained. Further, if the coefficient of thermal expansion is appropriately selected, the bending strength can be increased as compared with the chip type thermistor in which the glass layer is made of uncrystallized glass.

[0023]

EXAMPLES Next, the present invention will be described along with comparative examples in order to show specific embodiments of the present invention. The examples described below do not limit the technical scope of the present invention.

<Example> The chip type thermistor shown in FIGS. 1 to 3 was manufactured by the following method. First, commercially available manganese oxide, cobalt oxide, and copper oxide were used as starting materials, and the above metal oxides were weighed so that each of these metal elements had a predetermined atomic ratio. The weighed materials were uniformly mixed with a ball mill for 16 hours and then dehydrated and dried. Next, this mixture was calcined at 900 ° C. for 2 hours, and the calcined product was again pulverized with a ball mill and dehydrated and dried. 6% by weight of polyvinyl butyral, 30% by weight of ethanol and 30% by weight of butanol were added to the pulverized product to prepare a mixed slurry. Using this slurry, a 0.80 mm-thick green sheet was prepared by the doctor blade method, and this sheet was punched to a size of 70 mm in height and 70 mm in width. Next, this sheet is fired at 1200 ° C. for 4 hours, and is 50 m long.
A sintered sheet 11 having m, a width of 50 mm and a thickness of 0.65 mm was obtained (FIG. 3A).

SiO ₂ , MgO, ZnO and BaO having a glass transition temperature of about 650 ° C. and a crystallization temperature of about 750 ° C.
A first glass paste containing a raw material glass powder containing as a main component was prepared. The glass components were mixed uniformly in this paste. Then Si that does not crystallize at 780 ° C
A second glass paste containing a raw material glass powder containing O ₂ , PbO and K ₂ O as main components was prepared. After printing the first glass paste on both sides of the sintered sheet 11 and drying, the second glass paste was printed and dried on the dried first glass paste.

The sintered sheet 11 with the dried second glass paste is heated from room temperature to 780 ° C. at a rate of about 30 ° C./minute, held there for about 10 minutes, and cooled to room temperature at a rate of about 30 ° C./minute. Then, the glass layer 14 having a thickness of about 20 μm was formed on the surface of the sheet (FIG. 3B). The glass layer 14 is composed of a lower glass layer 14a made of crystallized glass formed of the first glass paste and an upper glass layer 14b made of amorphous glass formed of the second glass paste.

Next, this was cut into strips with a width of 1.20 mm using a diamond blade with a thickness of 0.10 mm (FIG. 3 (c)), and the cut surfaces on both sides of the strip 13 were described above. The first and second glass pastes were printed and fired by the same method as above to form the glass layer 14 having the same structure, and the four surfaces of the strip were covered with the glass layer 14 (FIG. 3 (d)). Subsequently, the strip-shaped body 13 was finely cut into chips having a length of 1.90 mm in a direction perpendicular to the cut surface obtained by the cutting (FIG. 3 (e)). This cut surface and the glass layer 1 around it
4 was coated with Ag paste. This chip 15 was heated from room temperature to 780 ° C. at a rate of about 30 ° C./minute, held there for about 10 minutes, and cooled to room temperature at a rate of about 30 ° C./minute to form a baked electrode layer. By this firing, the lower glass layer 14a of the four glass layers 14 became a crystallized glass having a crystallization rate of about 60%, and the upper glass layer 14b was an amorphous glass. The size of the obtained chip 15 is about 2.0 m in length.
m, the width was about 1.25 mm, and the thickness was about 0.75 mm.

Finally, the chip 15 is subjected to a plating treatment by an electrolytic plating method so that the surface of the baked electrode layer has a thickness of 2-3.
A Ni plating layer having a thickness of 4 μm and a Sn plating layer having a thickness of 4 to 5 μm were stacked to form a double-sided electrode surface layer. As a result, a chip type thermistor 10 having terminal electrodes 12 composed of an electrode layer and a plating layer formed on both ends thereof was obtained (FIG. 3).
(F)).

<Comparative Example 1> 780 the first glass paste
Except that it was prepared so as to contain a raw material glass powder containing SiO ₂ , PbO, and Na ₂ O as main components which do not crystallize at ℃.
A chip type thermistor was obtained according to the manufacturing method shown in FIG. The glass layer of this thermistor is composed of a lower glass layer made of amorphous glass formed on the surface of the thermistor body and an upper glass layer also made of amorphous glass formed on this lower glass layer. It was

In order to investigate the reliability of the chip type thermistors obtained in the examples and comparative examples, a high temperature storage test in which the thermistors were left in a high temperature atmosphere of 125 ° C. for 1000 hours and 8
A high-temperature and high-humidity test was conducted by leaving the sample in a high-temperature and high-humidity atmosphere having a relative humidity of 85% at 5 ° C. for 1000 hours. 20 samples for each test
Then, the rate of change in the resistance value of the thermistor was obtained from the following equation (1). The results are shown in Table 1. Resistance change rate = (R ₂ −R ₁ ) / R ₁ (1) where R ₁ is the resistance value before the test and R ₂ is the resistance value after the test.

[0031]

[Table 1]

As is clear from Table 1, the thermistor of the example having the lower glass layer of crystallized glass and the upper glass layer of amorphous glass showed a low rate of change in resistance value of less than 1 in both tests. On the other hand, the thermistor of the comparative example had a high value of about 4 in both tests. This proves that the thermistor of the example has excellent weather resistance and high reliability.

[Brief description of drawings]

FIG. 1 is an external perspective view of a chip thermistor of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

3A and 3B are views for explaining a manufacturing process of the chip type thermistor of FIG.

FIG. 4 is a cross-sectional view of a chip type thermistor provided with a resistance value adjusting internal electrode of the present invention.

FIG. 5 is a cross-sectional view of another chip-type thermistor provided with the internal electrode for adjusting the resistance value of the present invention.

6A and 6B are views for explaining a manufacturing process of the chip type thermistor of FIG.

FIG. 7 is a sectional view of another chip-type thermistor provided with the internal electrode for adjusting the resistance value of the present invention.

FIG. 8 is a sectional view of another chip-type thermistor provided with the internal electrode for adjusting the resistance value of the present invention.

FIG. 9 is a sectional view of another chip type thermistor provided with the internal electrode of the present invention.

[Explanation of symbols]

 10, 20, 30, 40 Chip type thermistor 11 Thermistor body 12 Terminal electrode 14 Glass layer 14a Lower glass layer 14b Upper glass layer 16 Baking electrode layer 18 Ni plating layer 19 Sn or Sn / Pb plating layer 21, 22, 23 Resistance Internal electrode for value adjustment

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideto Kataoka 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Sanryo Materials Co., Ltd., Ceramics Laboratory (72) Masami Koshimura 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Bamboo Sanryo Materials Co., Ltd. Ceramics Laboratory

Claims (4)

[Claims] 1. A thermistor element body (11), an insulating glass layer (14) covering the surface of the thermistor element body (11) excluding both end surfaces, and both end surfaces of the thermistor element body (11). And a pair of terminal electrodes (12, 12) provided at both ends including, the pair of terminal electrodes (12, 12) is a baking electrode layer formed at both ends of the thermistor element body (11) ( 16) and a chip-type thermistor (10) each having a plating layer (18, 19) formed on the surface of the baking electrode layer (16), part or all of the glass layer (14) is the surface of the element body. A lower glass layer (14a) made of crystallized glass formed above and an upper glass layer (14b) made of amorphous glass having a hermeticity formed on the lower glass layer (14a). ,
The glass transition point of the precursor glass of the crystallized glass is 40.
A chip type thermistor, which is in the range of 0 to 1000 ° C. and whose crystallization temperature is higher than the glass transition point. 2. The chip type thermistor according to claim 1, wherein the crystallized glass has a coefficient of thermal expansion of 40% or more and 100% or less of the coefficient of thermal expansion of the thermistor body (11). 3. The thermistor body (11) has internal electrodes (21, 22) for resistance value adjustment, which are electrically connected or not electrically connected to the terminal electrodes, on the surface of the body other than both end faces, and the glass layer ( The chip type thermistor according to claim 1, wherein 14) is configured to cover the surface of the element body other than both end surfaces including the internal electrodes (21, 22). 4. The thermistor element body (11) according to claim 1, which has a resistance value adjusting internal electrode (23) electrically connected or not electrically connected to the pair of terminal electrodes (12, 12) inside the element body. Chip type thermistor.