JP3149564B2 - Resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor capable of preventing variations in resistance characteristics, improving environmental resistance to humidity and the like, and improving power capacity and mechanical strength.

[0002]

2. Description of the Related Art Conventionally, a cermet resistor mainly composed of a Ru oxide or a Ru compound has been widely used as a resistance element having excellent accuracy. Such a resistor is formed, for example, by printing a resistor paste made of the above-mentioned Ru oxide or the like on the surface of an alumina substrate to form a thick resistor film,
Bake at 0-900 ° C. Then, a glass paste is applied to the surface of the resistive film of the alumina substrate and then baked to form a glass film, thereby improving environmental resistance to humidity and the like.

[0003]

However, in the above-mentioned conventional resistor, since the glass film is directly coated on the resistance film, there is a problem that the resistance value is liable to change and the characteristics are likely to vary. In addition, a pinhole may be formed in the glass film, and as a result, there is a problem that moisture or the like intrudes from the pinhole in a humid atmosphere to deteriorate resistance characteristics. Furthermore, in the above-mentioned conventional resistor, the thermal expansion coefficients of the alumina substrate, the resistive film, and the glass film are different from each other, so that the adhesiveness of the resistive film to the substrate is low, and as a result, a large power capacity cannot be obtained. Was the limit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and provides a resistor capable of avoiding variation in resistance characteristics, improving environmental resistance to humidity, and obtaining a large power capacity. It is an object.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides ZnO
A plurality of ceramics sheets having as a main component are laminated with a resistance film formed by printing a resistance paste containing Ru on the ceramics sheet interposed therebetween, and the laminated body is integrally sintered with the resistance film to form a rectangular parallelepiped. A resistor characterized in that a ceramic sintered body is formed, glass is diffused into the sintered body, and external electrodes electrically connected to the resistance film are formed on the surface of the sintered body.

Here, the glass material may be any material having a softening point not higher than the sintering temperature at the time of integrally sintering the ceramics and the resistive film and having an insulating property, and is not particularly limited. However, it is desirable to use one having excellent acid resistance and solvent resistance. As a means for diffusing the glass, a method of adding a varnish or the like to glass or a vitreous material to form a paste and attaching the paste to the surface of a sintered body, or melting and evaporating the glass material A method of heat-treating the sintered body in an atmosphere to diffuse and infiltrate it can be adopted, and the method is not particularly limited.

The resistance value can be arbitrarily controlled by changing the diffusion amount of the glass.
The temperature, time, or the like is appropriately set. Incidentally, the resistance value increases as the diffusion amount increases.

In order to manufacture the resistor, a plurality of ceramic sheets are laminated with the resistor film interposed therebetween, and the laminated body is sintered together with the resistor film to form a sintered body. Thereafter, glass is diffused from the outside into the sintered body.

[0009]

According to the resistor according to the present invention, a plurality of ceramic sheets mainly composed of ZnO are laminated with a resistance film containing Ru interposed therebetween, and the laminated body is integrally sintered to form a rectangular parallelepiped ceramic. Glass was diffused into the sintered body, and an external electrode connected to the resistance film was formed on the surface of the sintered body, so that the periphery of the resistance film was covered with ceramics, and the surface of the sintered body Is covered with a glass film, it is possible to avoid a variation in characteristics due to a change in resistance value as in the case where a conventional resistive film is directly coated with glass. Further, since the periphery of the resistance film is surrounded by a sintered body of the same material, heat dissipation can be improved, distortion due to a difference in thermal expansion can be reduced, and a large power capacity can be obtained. Furthermore, by diffusing glass into the sintered body, fine pores contained in the sintered body can be filled, so that problems caused by conventional pinholes can be solved and environmental resistance to humidity and the like can be improved. And life can be improved. Further, the mechanical strength of the resistor element can be improved by the diffusion of the glass.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and 2 are views for explaining a resistor according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a cermet resistor according to the present embodiment. The resistor 1 is constituted by burying a resistance film 4 made of Ru oxide or a compound thereof in a substantially rectangular ceramic sintered body 3. The left and right end faces 4a, 4b of the resistance film 4 are exposed on the left and right side faces 3a, 3b of the sintered body 3, and the remaining other end faces are the sintered body 3
Enclosed within. Further, external electrodes 5 made of Ag-Pd are formed on the left and right side surfaces 3a and 3b of the sintered body 3 so as to cover the respective end surfaces 4 of the resistance film 4.
a, 4b.

The sintered body 3 is formed by laminating a plurality of ceramic sheets 2 containing ZnO as a main component and a mixture of sub-additives to form a laminated body. It was formed as follows. In this case, the resistance film 4 is pattern-formed on the upper surface of one ceramic sheet 2 located at the center in the thickness direction, and the remaining ceramic sheet 2 is sandwiched on the ceramic sheet 2 on which the resistance film 4 is formed. Is superimposed.

A glass layer 6 is formed on the surface of the sintered body 3. The glass layer 6 accommodates the sintered body 3 and the glass powder in a magnetic container and heat-treats the glass container at a temperature equal to or higher than the softening point of the glass powder while rotating the magnetic container. It is formed by diffusing and penetrating into the body 3.

Next, the operation and effect of this embodiment will be described. According to the resistor 1 of this embodiment, the sintered body 3 has the resistance film 4
Is embedded and the glass layer 6 is formed, so that the periphery of the resistance film 4 is covered with the ceramics, so that the conventional glass coating can be eliminated, and the characteristic variation due to the change in the resistance value can be avoided accordingly. Further, since the glass is diffused to the outer surface portion of the sintered body 3, the pores in the sintered body 3 can be filled, and the problem of the pinhole can be solved. And the life characteristics can be improved.

Further, since the periphery of the resistance film 4 is surrounded by the ceramic material, the heat dissipation can be improved, the distortion due to the difference in the coefficient of thermal expansion can be reduced, and the power capacity can be improved accordingly. By the way, while the resistance value of the conventional resistance element was about 100 mW, the resistance body 1 of the present embodiment can achieve a power capacity of 2 to 10 times or more while reducing the size of the conventional element. .

Further, in this embodiment, by forming the glass layer 6 on the sintered body 3, the bending strength of the resistor 1 can be improved, and the resistance value can be controlled by changing the amount of diffusion of glass. It is possible to expand applications. Furthermore, since a plurality of resistance films 4 can be laminated, various resistors having different resistance values can be freely designed in the same pattern and the same process, and the application can be expanded from this point as well.

In the above embodiment, the case where the glass layer 6 is formed on the outer surface of the sintered body 3 has been described as an example. However, the present invention can be applied to the case where the glass layer 6 is diffused over the entire area of the sintered body 3. Alternatively, glass may be adhered to the surface of the sintered body.

Next, one method of manufacturing the resistor 1 of the present embodiment will be described. First, ZnO is used as a main component, and B
i, Sb, Co, Mn are represented by Bi ₂ O ₃ , Sb ₂ O ₃ , Co
1.0 mol% and 0.5 mol, respectively, in terms of O and MnO oxides
l%, 0.5 mol%, 0.5 mol% to form a ceramic powder. Pure water is added to the powder, and the mixture is pulverized and mixed by a ball mill to form a slurry.

Next, the slurry is evaporated to dryness to give 75
Pre-fire at 0 ° C for 2 hours. The calcined product is roughly pulverized, and pure water is added thereto, and finely pulverized by a ball mill to form a ceramic material. Next, a solvent in which ethyl alcohol and toluene are mixed at a ratio of 6: 4 is added to the raw materials, and mixed with a ball mill to form a slurry.

The above slurry is subjected to a doctor blade method.
After forming a green sheet having a thickness of 70 μm and drying the green sheet, the green sheet is cut into a predetermined size to form a large number of rectangular ceramic sheets 2.

Next, RuO ₂ : Ru ₂ Pb ₂ O ₇ : Ru
_A vehicle and glass are added to a composition prepared by mixing ₂ Bi ₂ O ₇ = 6: 2: 2 mol to form a resistance paste. This resistance paste is applied to the one ceramic sheet 2
The resistive film 4 is formed by printing on the upper surface of the substrate. In this case, the left and right end surfaces 4a and 4b of the resistance film 4 are
Are formed on the left and right outer edges, and the other end face is formed on the inside of the sheet 2.

Next, a plurality of ceramic sheets 2 are superimposed and laminated on the upper and lower surfaces of the ceramic sheet 2 on which the resistance film 4 is formed, and a pressure of ² t / cm ² is applied thereto and pressed. To form a laminate. Next, the laminate is cut into a predetermined size, heated to 400 ° C. to disperse the binder, and then heated to 930 ° C. and fired for 3 hours. obtain. The sintered body 3 thus obtained is barrel-polished.

The sintered body 3 is housed in a magnetic container, and a predetermined amount of borosilicate glass powder is put in the container. In this state, the glass container is heated to 800 ° C., which is higher than the softening point of the glass powder, while rotating, and heat-treated for 2 hours. By this heat treatment, the glass powder diffuses and penetrates into and adheres to the surface portion of the sintered body 3, whereby the glass layer 6 is formed.

Finally, the left and right side surfaces 3a of the sintered body 3
An electrode paste having an Ag: Pd = 7: 3 wt ratio is applied to 3b and baked at 850 ° C. for 10 minutes to form an external electrode 5. The external electrode 5 and the left and right end faces 4a, 4 of the resistive film 4 are formed.
b is electrically connected. Thereby, the resistor 1 of the present embodiment is manufactured.

[0024]

[Table 1]

[0025]

[Table 2]

Next, a test performed to confirm the effect of the resistor 1 of this embodiment will be described. This test is shown in Table 1.
As shown in Table 2 and Table 2, the addition amount of the borosilicate glass powder was in the range of 0.3 to 1.5 wt%, thereby changing the diffusion and adhesion amount of the glass. No. 7 was created. Then, the resistance value (Ω), 3 CV (3σ / average × 100%), power capacity (mW), and linearity (α) of the resistance value of each of the sample samples No. 3 to No. 7 were measured. The linearity _{α = 1 / log (R 1m} A /
R _{0.1 mA} ). In addition, the bending strength Kg of each of the above-mentioned examples and the rate of change of the resistance value after 96 hours were measured by a pressure cooker (2 atm, 100% RH) loaded with 1 W of electric power. For comparison, a comparative sample No. 1 without diffusion of glass and no heat treatment and a comparative sample No. 2 with only heat treatment without diffusion of glass were prepared, and the same measurement was performed. .

As is clear from Table 2, in the case of both Comparative Samples No. 1 and No. 2 which do not diffuse glass, any of the characteristics such as power capacity, linearity, and bending strength are at usable levels. However, a satisfactory value of 2.6, 2.3 kg in the transverse rupture strength and 5.2, 5.6% in the rate of resistance change was not obtained. On the other hand, each of the sample Nos. 3 to 7 in which the glass was diffused
In the case of, the variation in resistance value is 9.0 to 13%, and the power capacity is
Satisfactory values of 1360 to 1530 mW and linearity of 1.00 to 1.01 have been obtained. In addition, the transverse rupture strength is 3.2 to 4.3 kg, and the resistance change rate is 2.2 to 1.1%, which is significantly improved as compared with the comparative sample, indicating that the life characteristics are improved. Further, in the above-mentioned example samples No. 3 to No. 7, the resistance value increases as the amount of diffusion of the glass increases, which indicates that the resistance value can be arbitrarily set by controlling the amount of diffusion.

[0028]

As described above, according to the resistor of the present invention, a plurality of ceramic sheets mainly composed of ZnO are
Since the resistance film containing u is interposed and laminated and sintered integrally, glass is diffused into the sintered body, and an external electrode connected to the resistance film is formed on the surface of the sintered body. This has the effect of avoiding variations in the characteristics due to the change in the value, improving the environmental resistance to humidity, and improving the power capacity and the life characteristics.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a resistor according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a method for manufacturing the resistor of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resistor 3 Sintered body 4 Resistance film 6 Glass layer

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kokei Nakayama 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Inventor Shigeaki Go 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto No. 56 Murata Manufacturing Co., Ltd. (56) References JP-A-4-18701 (JP, A) JP-A-60-201601 (JP, A) JP-A-64-6701 (JP, A) JP-A 52-187 41856 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01C 7/00

Claims (1)

(57) [Claims] 1. A plurality of ceramics containing ZnO as a main component
The resistance sheet containing Ru in the ceramics sheet
Laminated with a resistive film formed by printing
Is sintered together with the above resistance film to form a rectangular parallelepiped ceramic.
When a sintered body is formed and glass is diffused into the sintered body,
In addition, the surface of the sintered body is electrically connected to the resistance film.
A resistor having an external electrode formed thereon.