JPH09232103A - Manufacturing method of chip thermistor - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: It is possible to obtain sufficient mechanical strength by preventing the occurrence of microcracks and the like, and it is possible to mass-produce at low cost. Furthermore, by suppressing variations in resistance value, the thermistor's original Functional accuracy can be improved. SOLUTION: After a large number of resistance value adjusting electrodes 15 are formed parallel to the surface of a thin plate material 16 made of a ceramic sintered body,
A large number of elongated holes 17 extending in a direction orthogonal to the longitudinal direction of the electrode are formed in this thin plate material, and a large number of prismatic portions 18 are formed between these elongated holes. After forming the insulating inorganic material layer 13 on all side surfaces of a large number of prismatic portions, the prismatic portions are cut along the center of each resistance value adjusting electrode in the width direction, and the resistance value adjusting electrodes are exposed at both ends. Thermistor body 12
To form Further, terminal electrodes 14, 1 made of a baked electrode layer and a plated layer are formed on both ends of the thermistor body including both end faces of the thermistor body and one end faces of a pair of resistance value adjusting electrodes.
4 is formed.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a method of manufacturing a chip type thermistor of this type, the present applicant has formed a resistance value adjusting electrode by printing a conductive paste in a strip shape on the surface of a thin plate material made of a ceramic sintered body, By cutting the thin plate material in a direction orthogonal to the longitudinal direction of the resistance value adjusting electrode to produce a strip, by cutting the strip along the center line in the width direction of the resistance adjusting electrode. A chip-shaped thermistor element body in which one end of the resistance value adjusting electrode is located at each end is prepared,
Further, a patent application was filed for a method of manufacturing a chip type thermistor in which terminal electrodes electrically connected to the resistance value adjusting electrodes are formed on both end surfaces of the thermistor body (Japanese Patent Laid-Open No. 12740/1992).
1).

This chip type thermistor is specifically manufactured by the following method. First, a conductive paste is formed in a strip shape on both sides or one side of a thin plate material made of a ceramic sintered body, printed with a screen printing method or a roll transfer printing method, and then dried to adjust resistance values in a large number of rows. Forming electrodes. Next, an insulating inorganic material layer is formed by printing, spraying or immersing a paste containing an insulating inorganic material such as glass on both sides of this thin plate material and then firing it.
After cutting a thin plate material whose both surfaces are coated with an insulating inorganic material layer in a strip shape in a direction orthogonal to the longitudinal direction of the resistance value adjusting electrode, a paste containing an insulating inorganic material on a cut surface of the strip material is formed. The insulating inorganic material layer is formed on the cut surface by printing, spraying or dipping and firing. Next, by cutting this strip in the direction orthogonal to its longitudinal direction, a chip-like thermistor element is produced, and a conductive paste is applied to both ends including both end surfaces that are cut surfaces of the thermistor element. A baked electrode layer is formed by applying and baking. Further, by forming a plating layer on the surface of this baked electrode layer, a chip type thermistor having terminal electrodes composed of the baked electrode layer and the plated layer at both ends is obtained.

In the method of manufacturing the chip type thermistor configured as described above, the resistance value adjusting electrode is formed on the surface of the thin plate material by the screen printing method, the roll transfer printing method or the like. The dimensional accuracy is higher than the method in which the thermistor element body is dipped therein. As a result, the resistance value adjusting electrodes can be formed with high accuracy, so that the interval between the resistance value adjusting electrodes can be formed with high dimensional accuracy. Further, since the resistance value adjusting electrode is formed on a ceramic sintered body, that is, on a thin plate material that has already been sintered, it is possible to prevent variation in dimensional accuracy due to firing shrinkage of the thin plate material.

[0005]

However, in the above-mentioned conventional method for manufacturing a chip type thermistor, since the thin plate material is cut into strips in a state where an insulating inorganic material layer such as glass is formed on the surface of the thin plate material, Due to the thermal stress caused by the difference in thermal expansion coefficient between the plate material and the insulating inorganic material layer (this thermal stress remains inside), micro cracks or the like occur in the thin plate material or the insulating inorganic material layer during the cutting, and the chip type There was a problem that the mechanical strength of the thermistor could not be obtained sufficiently. As a result, there has been a problem that sufficient performance cannot be obtained even in reliability tests regarding the strength of the chip type thermistor such as a substrate bending resistance test and a temperature cycle test. Further, in the above-described conventional method for manufacturing a chip type thermistor, in the glass layer forming step, it is necessary to form the glass layer in two steps, a sheet state and a strip state, and the ceramic sintered sheet is formed into a strip shape. In order to efficiently form a glass layer on this cut surface after cutting, it is necessary to align a large number of strips so that the cut surfaces face in the same direction, which also raises the manufacturing cost. It was Further, in the above-described conventional method for manufacturing a chip-type thermistor, when a strip-shaped product is cut to produce a chip-shaped thermistor element, a large number of strip-shaped products are arranged in the manufacturing process and the position of the resistance adjusting electrode However, if the size of the thermistor element body to be manufactured is small, the above-mentioned alignment is difficult and the resistance value of the completed chip-type thermistor may vary.

The object of the present invention is to obtain sufficient mechanical strength by preventing the occurrence of microcracks and the like, to be able to mass-produce inexpensively and in large quantities, and to suppress the variation in resistance value, which is the essential characteristic of the thermistor. An object of the present invention is to provide a method for manufacturing a chip type thermistor capable of improving the functional accuracy.

[0007]

The invention according to claim 1 is
As shown in FIGS. 1 and 7, the step of forming a large number of resistance value adjusting electrodes 15 in parallel with each other at a predetermined interval on the surface of a thin plate member 16 made of a ceramic sintered body, and the thin plate member 1
6 are provided with a predetermined interval in the longitudinal direction of the resistance value adjusting electrode 15 and a plurality of elongated holes 17 or deep grooves extending in a direction orthogonal to the longitudinal direction of the resistance value adjusting electrode 15 are formed between the elongated holes 17 or A step of forming a large number of prismatic portions 18 between the deep grooves, a step of forming an insulating inorganic material layer 13 on all side surfaces of at least a large number of the prismatic portions 18 of the thin plate material 16, and a prism having the insulating inorganic material layer 13 formed thereon. A step of forming the thermistor element body 12 in which the resistance value adjusting electrodes 15 are exposed at both ends by cutting the part 18 along the center of the resistance value adjusting electrodes 15 in the width direction, and A step of forming baking electrode layers 19, 19 on both ends of the thermistor element body 15 including both end surfaces and one end surface of the pair of resistance value adjusting electrodes 15, 15, and the baking electrode layers 19, 1.
A terminal electrode 1 formed by forming plating layers 20, 20 on the surface of 9 and baking electrode layers 19, 19 and plating layers 20, 20
4, 14 is a method of manufacturing a chip type thermistor. In the method of manufacturing the chip type thermistor, the cutting of the prismatic portion 18 after the formation of the insulating inorganic material layer 13 is performed only to form the end face of the thermistor element body 12, and thus the thermistor element body 12 or the insulating inorganic material layer 13 is not cut. No microcracks or the like will occur. Further, since the insulating inorganic material layer 13 can be formed on the prismatic portion 18 in one step without the work of aligning a large number of prismatic portions 18, the thermistor 11 can be inexpensively mass-produced. Further, when the prismatic portion 18 is cut into chips, a large number of prismatic portions 18 and the resistance value adjusting electrodes 15 formed on the surfaces thereof are already aligned.
The chip-shaped thermistor element body 12 obtained by cutting is uniform in size and the positional accuracy of the resistance value adjusting electrodes 15, 15 on the surface of each thermistor element body 12 is also uniform.

The invention according to claim 2 is, as shown in FIGS. 1, 2 and 7, a thin plate member 16 made of a ceramic sintered body.
A step of forming a large number of resistance value adjusting electrodes 15 in parallel with each other at a predetermined interval on the surface of the sheet, and a thin plate member 16 having a predetermined interval in the longitudinal direction of the resistance value adjusting electrodes 15 and for adjusting the resistance value. A step of forming a large number of prismatic portions 18 between the long holes 17 or the deep grooves by forming a large number of elongated holes 17 or deep grooves extending in a direction orthogonal to the longitudinal direction of the electrode 15, and a corner portion of the large number of prismatic portions 18 Rounding 18a,
A step of forming the insulating inorganic material layer 13 on all side surfaces of at least a large number of prismatic portions 18 of the thin plate member 16, and the prismatic portions 18 on which the insulating inorganic material layer 13 is formed,
5. A step of forming the thermistor element body 12 in which the resistance value adjusting electrodes 15 are exposed at both ends by cutting along the center of the width direction of 5, and for both end surfaces of the thermistor element body 12 and a pair of resistance value adjusting elements. Baking electrode layer 1 on both ends of the thermistor element body 15 including one end surfaces of the electrodes 15, 15.
9 and 19, and the baking electrode layer 1 by forming the plating layers 20 and 20 on the surface of the baking electrode layers 19 and 19.
Terminal electrodes 14 composed of 9, 19 and plated layers 20, 20;
14 is a method of manufacturing a chip type thermistor. In this chip type thermistor manufacturing method,
Since the corner portion 18a of the prismatic portion 18 of the thin plate member 16 is rounded, stress concentration does not occur in the portion of the insulating inorganic material layer 13 formed on all side surfaces of the prismatic portion 18 that covers the corner portion 18a. Therefore, the mechanical strength of the thermistor 11 can be further improved.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein, as shown in FIG. 9, the thin plate material 56 is used as the anode in the suspension 62 containing the insulating inorganic powder, and the counter electrode 6 is used.
3 and 63 are immersed as the cathode, and the thin plate material 56 and the counter electrode 6
3, 63 is applied with a predetermined voltage to attach insulating inorganic material powder to all side surfaces of at least a large number of prismatic portions 58 of the thin plate material 56 and baked, and an insulating inorganic material layer is formed on all side surfaces of at least a large number of prismatic portions 58. Is formed. In the method of manufacturing the chip type thermistor, the insulating inorganic material layer can be uniformly and simultaneously formed on the large number of prismatic portions 58 of the thin plate member 56.

[0010]

Next, a first embodiment of the present invention will be described in detail with reference to the drawings. The chip type thermistor 11 of the present invention shown in FIGS. 1 to 7 is manufactured by the following method. (A) Preparation of thin plate material 16 composed of ceramic sintered body First, one or more kinds of oxide powders of metals such as Mn, Fe, Co, Ni, Cu and Al are provided, and the metal atomic ratio becomes a predetermined ratio. As weigh each and
Mix for 10 hours, dehydrate and dry. Then, the mixture is calcined under atmospheric pressure at 500 to 1000 ° C. for 5 to 10 hours, pulverized again with a ball mill or the like, dehydrated and dried. Next, an organic binder or the like is added to this crushed product, and the crushed product is granulated to have a particle size of about 30 to 200 μm using a spray dryer or the like, and compression-molded into a rectangular parallelepiped by a hydraulic press or the like. Furthermore, this molded product is 1000-130 under atmospheric pressure.
By firing at 0 ° C. for 5 to 10 hours to prepare a ceramic sintered block having a predetermined size, and cutting this block into a predetermined thickness using a band saw or the like, the thin plate material 16 is manufactured (FIG. 1). (A)).

(A) Formation of the resistance adjusting electrode 15 on the surface of the thin plate member 16 A strip-shaped conductive paste having a width of 0.1 to 2.5 mm is formed on both surfaces of the thin plate member 16 in the width direction of 0.1 to 2.5 mm. Print at intervals of 3 mm and dry. . At this time, printing is performed so that the conductive pastes on both sides of the thin plate member 16 face each other with the thin plate member 16 interposed therebetween. This thin plate material 16 is heated to 700 to 850 ° C. under atmospheric pressure.
Then, a large number of rows of resistance adjusting electrodes 15 having a thickness of 5 to 20 μm are formed on both surfaces of the thin plate member 16 (FIG. 1A).
The conductive paste is Ag paste or Ag-P.
A d-paste or the like is used, and the conductive paste may be printed on one side of the thin plate material instead of both sides. Further, a thin film electrode of 0.1 to 1 μm may be formed by using a resinate paste such as Au. (C) Forming long holes 17 in the thin plate member 16 A large number of the thin plate members 16 are provided at predetermined intervals in the longitudinal direction of the resistance value adjusting electrode 15 and extend in a direction orthogonal to the longitudinal direction of the resistance value adjusting electrode 15. The large number of long holes 17 are formed by using a dicing machine or the like.
A large number of prismatic portions 18 are formed between them (Fig. 1 (b) and Fig. 2).
(A)). The width of the long hole 17 and the width of the prismatic portion 18 are preferably formed to be 0.05 to 0.5 mm and 0.4 to 1.6 mm, respectively. Further, the corner portion 18a of the prismatic portion 18
Is subjected to a blasting process in which fine alumina powder or the like is sprayed, and then the corner portion 18a is polished so that the corner portion 18a is rounded with a radius of curvature of 0.01 to 0.1 mm (FIG. 2). (B)).

(D) Formation of Insulating Inorganic Material Layer 13 on All Sides of Square Pillar 18 A paste containing insulating inorganic powder such as glass powder and having a predetermined viscosity on all sides of the prism 18 of the thin plate member 16 described above. After spraying, dry. This thin plate material 16 is
The temperature is maintained at 00 to 1000 ° C. for 1 to 20 minutes, and the insulating inorganic material layer 13 having a thickness of 2 to 50 μm is formed on all side surfaces of the prismatic portion 18 (FIG. 1C, FIG. 3 and FIG. 4). The paste may be sprayed not only on the prismatic portion but also on the entire thin plate material. (E) Cutting of the thin plate material 16 on which the insulating inorganic material layer 13 is formed. A large number of prismatic portions 18 having the insulating inorganic material layer 13 formed on all side surfaces are provided along the center in the width direction of each resistance value adjusting electrode 15. Chips are cut using a dicing machine or the like in a direction orthogonal to the longitudinal direction of the prismatic portion 18, that is, in the direction of the solid line arrow in FIG. This disconnection
The thermistor element body 12 is obtained in which all side surfaces are covered with the insulating inorganic layer 13 and the resistance value adjusting electrodes 15 are exposed at both ends. The length of the thermistor element body 12 is 0.
It is preferably formed in a range of 5 to 5 mm.

(F) Formation of terminal electrodes 14, 14 on both ends of the thermistor element body 12. First, both end surfaces of the chip-like thermistor element body 12 and one end surfaces of a pair of resistance value adjusting electrodes 15, 15 are included. The baked electrode layers 19 and 19 are formed by applying a conductive paste containing a noble metal powder and an inorganic binder to both ends of the thermistor body 12 and baking the applied paste. Next, the baking electrode layer 19,
19 is used as a base electrode layer, and plating layers 20, 20 are formed on this surface.
To form the baking electrode layers 19 and 19 and the plating layer 20,
A chip type thermistor 11 having terminal electrodes 14 and 14 composed of 20 is obtained (FIG. 1E, FIG. 6 and FIG. 7).

8 and 9 show a second embodiment of the present invention. In this embodiment, a large number of deep grooves 57 are formed in the thin plate material 56 at predetermined intervals in the longitudinal direction of the resistance value adjusting electrode 55 and extend in a direction orthogonal to the longitudinal direction of the resistance value adjusting electrode 55. A large number of prismatic portions 58 are formed between a large number of deep grooves 57, and an insulating inorganic material layer is formed on all side surfaces of the large number of prismatic portions 58 using an electrodeposition device 61. As shown in detail in FIG. 9, the electrodeposition device 61 is a container in which a suspension 62 containing insulating inorganic powder such as glass powder in a predetermined ratio is stored, and a thin plate member 56 immersed in the suspension 62. And counter electrodes 63, 63 which are immersed at a predetermined interval,
The thin plate member 56 is used as an anode, the counter electrodes 63, 63 are used as cathodes, and a power source 64 for applying a predetermined voltage to both is provided. Using the above electrodeposition apparatus 61, the thin plate material 56 on which the insulating inorganic powder is electrodeposited on all the side surfaces is heated to 500 to 1000 ° C. under atmospheric pressure.
By keeping it for 20 minutes, an insulating inorganic layer having a thickness of 2 to 50 μm is formed. Since the manufacturing method other than the above is substantially the same as the manufacturing method of the chip type thermistor of the first embodiment, the repeated description will be omitted.

[0015]

Next, examples of the present invention will be described in detail together with comparative examples. <Embodiment 1> As shown in FIGS. 1 to 7, a chip type thermistor manufactured by the following method was used as Embodiment 1. First, manganese carbonate, nickel carbonate, and cobalt carbonate were used as starting materials, and these were weighed so that the metal atomic ratio was a predetermined ratio, uniformly mixed in a ball mill for 16 hours, dehydrated and dried. This mixture was calcined at 900 ° C. under atmospheric pressure for 2 hours, ground again with a ball mill, dehydrated and dried. An organic binder was added to this pulverized product, and the pulverized product was granulated by a spray dryer so that the particle size was about 60 μm, and compression molded into a rectangular parallelepiped by a hydraulic press. This molded product is fired at 1200 ° C. under atmospheric pressure for 4 hours to produce ceramic sintered blocks having lengths, widths, and thicknesses of 35 mm, 50 mm, and 10 mm, respectively, and the blocks are cut with a band saw to obtain length, width, and thickness. Thin plate materials 16 having a thickness of 35 mm, 50 mm, and 0.65 mm were manufactured (FIG. 1A).

Next, a width of 0.6 m is provided on both sides of the thin plate member 16.
m strip-shaped Ag paste was printed at intervals of 0.9 mm in the width direction and dried. At this time, A on both sides of the thin plate material 16
The g-type paste was printed so as to face each other with the thin plate member 16 interposed therebetween. The thin plate member 16 was held at 820 ° C. under atmospheric pressure, and a plurality of rows of resistance value adjusting electrodes 15 having a thickness of about 10 μm were formed on both surfaces of the thin plate member 16 (FIG. 1A). A large number of elongated holes 17 having a width of 0.1 mm and extending in a direction orthogonal to the longitudinal direction of the resistance value adjusting electrode 15 are formed in the thin plate member 16 with a width of 0.65.
A large number of prismatic portions 18 having a width of 0.65 mm were formed between the large number of long holes 17 by forming them with a dicing machine at intervals of mm (FIGS. 1B and 2).
(A)). After performing a blasting process in which fine alumina powder is sprayed on the corner portion 18a of the prismatic portion 18, the corner portion 18a of the prismatic portion 18 is polished, and the corner portion 18a is rounded with a radius of curvature of 0.05 mm. (Fig. 2
(B)).

Next, a paste containing glass powder and having a predetermined viscosity was sprayed on all side surfaces of the prismatic portion 18 of the thin plate member 16 and then dried. This thin plate material 16 is heated to 850
The glass layer 13 having a thickness of about 20 μm was formed on all side surfaces of the prismatic portion 18 by holding the glass layer 13 at about 10 ° C. for about 10 minutes (FIG. 1).
(C), FIGS. 3 and 4). The prismatic portion 18 on which the glass layer 13 is formed is cut into chips using a dicing machine in the direction perpendicular to the longitudinal direction of the prismatic portion 18 along the center of the resistance value adjusting electrodes 15 in the width direction. , Length 1.5
mm chip-shaped thermistor body was prepared (Fig. 1
(D) and FIG. 5). One end faces of the resistance value adjusting electrodes 15 and 15 are exposed at both ends of the thermistor body.

Further, Ag paste is applied to both ends of the thermistor body 12 including both end faces of the thermistor body 12 and one end faces of the pair of resistance value adjusting electrodes 15, 15 by a dipping method, and then at 820 ° C. under atmospheric pressure. Then, the baked electrode layers 19 and 19 were formed on both ends of the thermistor element body 12 by holding for 10 minutes. The baked electrode layers 19, 19
Plating layers 20 and 20 were formed on the surface of (FIGS. 6 and 7). The plating layers 20, 20 are the above-mentioned baked electrode layers 19, 1
2-5μ formed on the surface of 9 by the electrolytic barrel method
m Ni plating layers 20a, 20a and Ni plating layer 20
a, 20a and solder-plated layers 20b, 20b having a thickness of 3 to 7 [mu] m. In this way, the chip type thermistor 11 shown in FIG. 1 (e), FIG. 6 and FIG.
I got

<Embodiment 2> As shown in FIGS. 8 and 9,
A chip type thermistor manufactured by the following method was used as Example 2. A thin plate material 56 was produced in the same manner as in Example 1, and a large number of deep grooves 57 having a width of 0.1 mm were formed in the thin plate material 56 by a dicing machine at intervals of a width of 0.65 mm. A large number of prismatic portions 58 having a width of 0.65 mm were formed between them (FIG. 8). A portion of the thin plate member 56 where the deep groove 57 is not formed is formed by the metal plates 65, 6
5 and the prismatic portion 58 was immersed in the suspension 62 (FIG. 9). This suspension 62 uses a mixed solution obtained by converting 5% by volume of water in isopropyl alcohol as a solvent, and 0.5 g of glass powder (GA44 manufactured by Nippon Electric Glass Co., Ltd.) is added to 1 liter of this solvent. It was adjusted. Further, the suspension 62 has a pair of opposed electrodes 63, which sandwich the thin plate material 56 from both sides of the thin plate material 56 at predetermined intervals.
63 was immersed. The thin plate material 56 serves as an anode, the pair of opposing electrodes 63, 63 serves as a cathode, and a direct current of 600 V is applied between them.
By applying for 0 minutes, glass powder was electrodeposited on all side surfaces of the prismatic portion 58 of the thin plate member 56. The thin plate material 56 on which the glass powder was electrodeposited was kept at 850 ° C. under atmospheric pressure for about 10 minutes to form a glass layer having a thickness of about 30 μm on all side surfaces of the prismatic portion 58.
A chip type thermistor was manufactured by the same method as in the first embodiment except the above.

<Comparative Example 1> Although not shown, a chip type thermistor manufactured by the following method was used as Comparative Example 1. First, electrodes for resistance value adjustment were formed on both surfaces of a thin plate material made of a ceramic sintered body having a thickness of 0.65 mm in the same manner as in Example 1, and a paste containing glass was printed on both surfaces of this thin plate material. A glass layer was formed by firing. This thin plate material, both surfaces of which were covered with glass layers, was cut into a strip shape having a width of 0.65 mm in a direction orthogonal to the longitudinal direction of the resistance value adjusting electrode, and then the cut surface of the strip material contained glass. A glass layer was formed on the cut surface by printing the paste and firing it. Next, the strip-shaped material is cut in a direction orthogonal to the longitudinal direction to obtain a length of 1.
A 5 mm chip-shaped thermistor body was produced. Further, terminal electrodes were formed on both ends of the thermistor element body in the same manner as in Example 1 to obtain a chip type thermistor.

<Comparative Test and Evaluation> With respect to the chip type thermistors of Example 1 and Comparative Example 1, a bending strength test and a substrate bending resistance test were conducted. Table 1 shows the results.

[0022]

[Table 1]

As is clear from Table 1, the chip thermistor manufactured by the method according to the present invention has improved bending strength and substrate bending resistance over the chip thermistor manufactured by the conventional method. I knew that.

[0024]

As described above, according to the present invention, a large number of long holes or deep grooves are formed in a thin plate material having a large number of resistance value adjusting electrodes formed on its surface in a direction orthogonal to the electrodes, An insulating inorganic material layer is formed on all side surfaces of a large number of prisms formed between long holes or deep grooves, and both ends are formed by cutting the prisms along the center of each resistance value adjusting electrode in the width direction. Forming a thermistor element body in which the resistance value adjusting electrodes are exposed respectively, and further, a baking electrode layer and a plating layer are formed on both end portions of the thermistor element body including both end surfaces of the thermistor element body and one end surfaces of the pair of resistance value adjusting electrodes. Since, since the cutting of the prismatic portion after forming the insulating inorganic layer is only the cutting that forms the end face of the thermistor body, micro cracks or the like do not occur in the thermistor body or the insulating inorganic layer. . Further, in comparison with the conventional method for manufacturing a chip type thermistor in which the glass layer is formed in two steps and a large number of strips need to be aligned so that their cut surfaces face in the same direction, In the manufacturing method of chip type thermistor,
Since it is only necessary to form the insulating inorganic material layer on the prisms once without the work of aligning a large number of prisms, it is possible to mass-produce the thermistors at low cost.

Further, when a large number of strip-shaped objects are arranged and cut, if the size of the thermistor body obtained by cutting is small, it is difficult to align the resistance value adjusting electrodes.
Compared with the conventional chip-type thermistor manufacturing method in which the resistance value of the completed thermistor varies, in the chip-type thermistor manufacturing method of the present invention, when the prismatic portion is cut into chips, a large number of prisms are already formed. Since the electrodes and the resistance value adjusting electrodes formed on these surfaces are aligned, the chip-shaped thermistor element body obtained by cutting the prismatic section has uniform dimensions, and the thermistor element bodies The positional accuracy of the resistance adjusting electrode on the surface is also uniform. Further, in the above manufacturing method, a step of forming a large number of prismatic portions between long holes or deep grooves by forming a large number of long holes or deep grooves in a thin plate material, and an insulating inorganic material layer on all side surfaces of these prismatic portions. If a step of rounding the corners of a large number of prisms is added between the step of forming and the step of forming a stress, stress concentration will occur on the part of the insulating inorganic layer formed on all sides of the prism that covers the corners. Does not occur, and the mechanical strength of the thermistor can be further improved. Further, the thin plate material is immersed in a suspension containing insulating inorganic powder as an anode and the counter electrode as a cathode, and a predetermined voltage is applied to the thin plate material and the counter electrode so that at least a large number of prismatic portions of all sides of the thin plate material are covered. If the insulating inorganic substance powder is adhered to and baked, and the insulating inorganic substance layer is formed on all side surfaces of at least a large number of prismatic portions, the insulating inorganic substance layer can be uniformly and simultaneously formed on a large number of prismatic portions of the thin plate material. As a result, the manufacturing cost of the thermistor can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a manufacturing process of a chip type thermistor according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 (b) showing a state before and a state after rounding the corner portion of the prismatic portion.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view taken along the line CC of FIG.

FIG. 5 is a sectional view taken along line DD of FIG.

FIG. 6 is a perspective view showing a judgment of a main part of the thermistor.

7 is a sectional view taken along line EE of FIG.

FIG. 8 is a perspective view of a thin plate member having a large number of deep grooves according to a second embodiment of the present invention.

FIG. 9 is a configuration diagram showing a state in which the thin plate material is immersed in a suspension and a voltage is applied.

[Explanation of symbols]

 11 Chip Thermistor 12 Thermistor Element 13 Glass Layer (Insulating Inorganic Material Layer) 14 Terminal Electrode 15,55 Resistance Adjustment Electrode 16,56 Thin Plate Material 17 Long Hole 18,58 Square Column 18a Corner 19 Baking Electrode 20 Plating Layer 57 Deep groove 62 Suspension 63 Counter electrode

Claims (3)

[Claims] 1. A thin plate material (16, 5) made of a ceramic sintered body.
A step of forming a large number of resistance value adjusting electrodes (15, 55) parallel to each other at a predetermined interval on the surface of 6), and the resistance value adjusting electrodes (15, 55) on the thin plate material (16, 56). 55) with a predetermined interval in the longitudinal direction of the resistance adjustment electrode (1
5,55) with a large number of long holes (1
7) or a step of forming a large number of prismatic portions (18, 58) between the elongated holes (17) or between the deep grooves (57) by forming deep grooves (57), and the thin plate material (16, 56) At least the plurality of prismatic portions
(18, 58) a step of forming an insulating inorganic material layer (13) on all side surfaces, the prismatic portion (18, 58) on which the insulating inorganic material layer (13) is formed on each of the resistance value adjusting electrodes ( 15, 55) forming a thermistor element body (12) in which the resistance value adjusting electrodes (15, 55) are exposed at both ends by cutting along the center of the thermistor element body. The thermistor element body including both end faces of (12) and one end faces of the pair of resistance value adjusting electrodes (15, 55)
(12) a step of forming a baking electrode layer (19, 19) on both ends, and a plating layer (20, 20) is formed on the surface of the baking electrode layer (19, 19) to form the baking electrode layer (19 , 19) and the plating layer (20, 20)
And a step of forming terminal electrodes (14, 14) made of 2. A thin plate material (16, 5) made of a ceramic sintered body.
A step of forming a large number of resistance value adjusting electrodes (15, 55) parallel to each other at a predetermined interval on the surface of 6), and the resistance value adjusting electrodes (15, 55) on the thin plate material (16, 56). 55) with a predetermined interval in the longitudinal direction of the resistance adjustment electrode (1
5,55) with a large number of long holes (1
7) or a step of forming a large number of prismatic portions (18, 58) between the elongated holes (17) or between the deep grooves (57) by forming deep grooves (57), and a large number of the prismatic portions (18, 58). 58) rounding the corner portion (18a), and at least the plurality of prismatic portions of the thin plate materials (16, 56)
(18, 58) a step of forming an insulating inorganic material layer (13) on all side surfaces, the prismatic portion (18, 58) on which the insulating inorganic material layer (13) is formed on each of the resistance value adjusting electrodes ( 15, 55) forming a thermistor element body (12) in which the resistance value adjusting electrodes (15, 55) are exposed at both ends by cutting along the center of the thermistor element body. The thermistor element body including both end faces of (12) and one end faces of the pair of resistance value adjusting electrodes (15, 55)
(12) a step of forming a baking electrode layer (19, 19) on both ends, and a plating layer (20, 20) is formed on the surface of the baking electrode layer (19, 19) to form the baking electrode layer (19 , 19) and the plating layer (20, 20)
And a step of forming terminal electrodes (14, 14) made of 3. A thin plate material (16,56) is immersed in a suspension (62) containing an insulating inorganic powder as an anode and a counter electrode (63,63) as a cathode to form the thin plate material (16,56). Applying a predetermined voltage to the counter electrodes (63, 63) and attaching the insulating inorganic powder to all side surfaces of at least a large number of prismatic portions (18, 58) of the thin plate material (16, 56) and baking. , At least the large number of prisms (18,5
The method for manufacturing a chip type thermistor according to claim 1 or 2, wherein the insulating inorganic material layer (13) is formed on all side surfaces of (8).