JPH0634201U - Stacked thermistor - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the resistance of the laminated thermistor and suppress variations in resistance. [Structure] A pair of internal electrodes 2 to 7 is provided on each virtual plane passing through P1, P2, and P3 in the resistor 1. The inner electrodes 2, 4, 6 on one side are connected to the first outer electrode 8, and the inner electrodes 3, 5, 7 on the other side are connected to the second outer electrode 9.
Connect to. The internal electrodes 2, 4, 6 on one side and the internal electrodes 3, 5, 7 on the other side do not overlap with each other when viewed from the direction perpendicular to the upper surface of the resistor 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a laminated thermistor for use in temperature compensation, current control, temperature detection, etc. of electronic devices.

[0002]

[Prior art]

 A typical thermistor is composed of a prismatic or plate-shaped thermistor resistor and a pair of electrodes formed at both ends by a dipping method or the like. This type of thermistor has the advantage that it can be manufactured at low cost due to its simple structure, but on the other hand, it is difficult to set the mutual distance between a pair of electrodes to a predetermined value, and therefore it has the drawback that the resistance value varies. . Further, it is difficult for this thermistor to secure a predetermined breakdown voltage and obtain a low resistance value.

In order to solve the above-mentioned problem, as shown in FIG. 5, first and second internal electrodes 11 and 12 are arranged in the thermistor resistor 10, and the first and second internal electrodes 11 and 12 are arranged in the thermistor resistor 10. It is known, for example, from Japanese Patent Publication No. 50-11585 to connect to the second external electrodes 13 and 14 to form a laminated structure similar to a laminated ceramic capacitor. With this configuration, the facing area of the first and second internal electrodes 11 and 12 becomes large, and when the number of laminated layers is increased, a plurality of internal electrodes are connected in parallel, so that the initial resistance value (resistance at 25 ° C. Value) and the thermistor constant generally called B constant can be reduced.

[0004]

[Problems to be solved by the device]

 However, when the laminated structure is adopted, the pattern shift between the first internal electrode 11 and the second internal electrode 12 is likely to occur, and the resistance value changes when the facing area of the two changes. That is, it is difficult to obtain a thermistor having a resistance value as designed. Further, if the laminated structure is used, it is possible to easily reduce the resistance, but the resistance decrease rate becomes too large as the number of laminated layers increases. Therefore, if the resistance value is changed by changing only the number of stacked layers without changing the internal electrode pattern, it becomes difficult to obtain a thermistor having a target resistance value.

Therefore, an object of the present invention is to provide a laminated thermistor capable of reducing the variation in resistance value and easily obtaining a target resistance value.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a thermistor resistor made of a resistance material whose resistance value changes in response to temperature changes, and a pair of thermistor resistors arranged on a plurality of parallel virtual planes in the resistor. Internal electrodes and first and second external electrodes provided on both side surfaces of the resistor, one of the pair of internal electrodes being connected to the first external electrode, and the pair of internal electrodes. The other is connected to the second external electrode, and the one internal electrode and the other internal electrode are arranged so as not to overlap each other when viewed from a direction perpendicular to the virtual plane. It is related to.

[0007]

[Operation and effect of the device]

 In the present invention, since the resistance value of the thermistor is determined by the distance between the pair of inner electrodes arranged on the same virtual plane, the variation in resistance value is reduced. That is, since a pair of internal electrodes on the same virtual plane are formed at the same time, the mutual spacing between them is irrelevant to the stacking deviation, and the variation in the resistance value is reduced. Also, since the resistance value between a pair of internal electrodes on the same virtual plane can be reduced, the change in the overall resistance value due to the change in the number of laminated layers can be reduced, and thermistors with various resistance values can be easily obtained. be able to. That is, thermistors having various resistance values can be obtained by changing the number of laminated layers without changing the pattern of the internal electrodes.

[0008]

【Example】

 Next, a laminated NTC thermistor according to an embodiment of the present invention will be described with reference to FIGS. The thermistor shown in FIG. 1 comprises a resistor 1 made of an NTC thermistor material, first, second, third, fourth, fifth and sixth internal electrodes 2, 3, 4, 5, 6, 7; It is composed of first and second external electrodes 8 and 9. The first and second internal electrodes 2 and 3 are parallel to the upper surface of the rectangular parallelepiped-shaped resistor 1 and on the first imaginary plane passing through the first position P1 in the thickness direction to form the pattern shown in FIG. The formed Ag-Pd conductor layers are formed, and one ends of these are separated from each other with a distance L. The third and fourth internal electrodes 4, 5 are formed of Ag-Pd conductor layers in a pattern similar to that shown in FIG. 3 on a second virtual plane passing through P2. The fifth and sixth internal electrodes 6, 7 are formed of Ag-Pd conductor layers in a pattern similar to that of FIG. 3 on a third virtual plane passing through P3. The first, second and third virtual planes passing through P1, P2 and P3 are parallel to each other.

The first, third, and fourth inner electrodes 2, 4, 6 arranged on the left side in FIG. 1 are exposed on one side surface, and are formed on the first outer electrode 8 made of an Ag—Pd conductor layer. It is connected. In FIG. 1, the second, fourth, and sixth inner electrodes 3, 5, 7 arranged on the right side are exposed on the other side surface and connected to the second outer electrode 9 composed of an Ag-Pd conductor layer. There is.

Next, a method of manufacturing the thermistor will be described with reference to FIG. First, a valence control agent and a sintering aid are added to a predetermined amount of manganese oxide and cobalt oxide, stirred in a wet ball mill, dehydrated and dried, calcined, and again stirred in a wet ball mill and dehydrated. Then, it was dried to obtain a powder of ceramic / NTC thermistor material. Next, a predetermined amount of a polyvinyl butyral-based organic binder, a plasticizer, and a toluene-based solvent were added to this powder, and the mixture was stirred with a wet ball mill to remove the cells to obtain a slurry. Next, using this slurry, a plurality of green sheets (unfired ceramic sheets) having a thickness of 50 μm were formed by a doctor blade method. As shown in FIG. 4, the green sheets 1a to 1d are formed in a large area so that a large number of thermistors can be obtained from one sheet. Next, conductor layers 2a to 7a for obtaining the first to sixth internal electrodes 2 to 7 are screen-printed with Ag-Pd paste on the first, second and third green sheets 1a, 1b and 1c. Formed by. Next, the first, second, third, and fourth green sheets 1a, 1b, 1c, and 1d are laminated in the order shown in FIG. 4 and pressure-bonded, and then the position shown by the broken line in FIG. 4 is cut. To obtain a thermistor compact, and to remove the binder, the compact is heated in air at 400 ° C for 2 hours, and then fired in air at 1100 ° C for 2 hours to obtain the resistance shown in Figs. 1 and 2. I got body 1. Finally, the first and second external electrodes 8 and 9 were formed by applying and baking an Ag-Pd paste on both side surfaces of the resistor 1.

In the laminated thermistor of this embodiment, the first, third and fifth inner electrodes 2, 4, 6 connected to the first outer electrode 8 and the second outer electrode 9 were connected. The second, fourth, and sixth internal electrodes 3, 5, and 7 do not overlap with each other when viewed in a direction perpendicular to the virtual plane. Therefore, the resistance value does not change due to the pattern shift that can be placed during stacking.

[0012]

[Modification]

 The present invention is not limited to the above-mentioned embodiments, and the following modifications are possible, for example. (1) The structure having the layers having the fifth and sixth internal electrodes 6 and 7 may be omitted, or the number of layers having the internal electrodes may be increased similarly to the first to sixth internal electrodes 2 to 7. it can. (2) In FIG. 4, one cover green sheet 1d is arranged on the upper side, but more cover green sheets can be arranged on the upper and lower sides. (3) Without forming the first and second external electrodes 8 and 9 after firing, the conductor paste can be applied to the molded body before firing to form the internal electrodes and the external electrodes at the same time. Also, the first and second external electrodes 8 and 9 can be formed by a plating method, a dipping method, or the like.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view showing a laminated thermistor according to an embodiment of the present invention.

FIG. 2 is a perspective view of the thermistor of FIG.

3 is a plan view showing an electrode pattern at a position P1 in FIG. 1. FIG.

FIG. 4 is a diagram showing a method of manufacturing the thermistor of FIG.

FIG. 5 is a cross-sectional view showing a conventional laminated thermistor.

[Explanation of symbols]

 1 Resistor 2-7 Internal electrode 8,9 External electrode

Claims (1)

[Scope of utility model registration request] 1. A thermistor resistor made of a resistance material whose resistance value changes according to temperature change, a pair of internal electrodes respectively arranged on a plurality of virtual planes parallel to each other in the resistor, and the resistance. First and second external electrodes provided on both side surfaces of the body, and one of the pair of internal electrodes is connected to the first external electrode, and the other of the pair of internal electrodes is the second external electrode.
Connected to external electrodes of the above, and the one internal electrode and the other internal electrode are arranged so as not to overlap each other when viewed in a direction perpendicular to the virtual plane.