JPH0590017A - Manufacture of insulating substrate for chip-shaped variable resistance - Google Patents

Abstract

PURPOSE:To prevent the degradation of dimensional accuracy of an insulating substrate due to a conductive paste for electrode film, with which the surface and the rear surface of a ceramic blank sheet are coated and that the transfer operation of the ceramic blank sheet is distributed when a plurality of insulating substrates for chip-shaped variable resistance, which are provided with an electrode film are manufactured simultaneously by using one ceramic blank sheet. CONSTITUTION:Blank parts A4, A5 having a proper width are connected to and brought into contact with both the right and left faces of a ceramic blank sheet A integrally via stripe lines B2 for breaking use. The blank parts A4, A5 are cut and removed after a surface electrode film 5a and a rear-surface electrode film 5c out of electrode films 5 have been formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type variable resistor having a variable resistance value, and a method of manufacturing a ceramic insulating substrate having a resistance film and electrode films on both ends of the resistance film. Is.

[0002]

2. Description of the Related Art Generally, as shown in FIGS. 1 to 3, a chip type variable resistor of this type has a resistance film 3 concentric with a central hole 2 on an upper surface of a ceramic chip type insulating substrate 1. On the other hand, a pair of electrode projections 4 formed so as to project from the side surface of the insulating substrate 1 are formed with electrode films 5 for both ends of the resistance film 3, and a sliding contact with the resistance film 3 is made. The moving element 6 is rotatably attached to the shaft 7 inserted through the center hole 2.

The electrode films 5 of the projections 4 for both electrodes are the upper surface electrode film 5a formed on the upper surface of the insulating substrate 1 so as to contact the resistance film 3 and the side surfaces formed on the side surfaces of the projections 4. The lower electrode film 5b formed on the lower surface of the insulating substrate 1 and the lower electrode film 5c formed on the lower surface of the insulating substrate 1 have a central electrode 8 electrically connected to the slider 6 on the shaft 7. It is integrally molded so as to be located in the recess 9 formed in the.

When manufacturing the insulating substrate 1 having the resistance film 3 and the electrode films 5 in this chip type variable resistor, the inventor of the present invention filed a prior patent application (Japanese Patent Application No. 63-63).
No. 2,920,961 and JP-A No. 2-137201) proposed the following method. That is, as shown in FIG. 9, first, the ceramic material plate A and the plurality of insulating substrates 1 are attached to the electrode projections 4 on each insulating substrate 1.
Of the two-row ceramic material plates A ₁ which are arranged in two rows so as to face outward, are integrally formed at the electrode projections 4 in each insulating substrate 1 of each of these three two-row ceramic material plates A _1. And the margin tabs A ₂ and A ₃ are integrally connected to both ends of the margins, and the margins between the insulation boards 1 and between the insulation board 1 and the margins of both margins. A score line B for break is provided between the pieces A ₂ and A ₃ to form a rectangular shape having a length dimension L and a width dimension S.

With the lower surface of the ceramic material plate A facing upward, a conductive paste is applied by screen printing to the electrode projections 4 of each insulating substrate 1 as shown in FIG. By firing, the lower surface electrode film 5c of the electrode film 5 is formed, and then the ceramic material plate A is placed with the upper surface thereof facing upward as shown in FIG. A conductive paste is applied to the places by screen printing, dried and baked to form the upper electrode pole film 5a in the electrode film 5, and then the paste forming the resistance film 3 at the places of each insulating substrate 1. Is applied in an arc shape by screen printing, and then dried and baked to form the resistance film 3.

Then, the ceramic material plate A is shown in FIG.
As shown in FIG. 2, after breaking each of the three double-row ceramic material plates A ₁ along the score line B, the tip end portion of the protrusion 4 in each insulating substrate 1 of each two-row ceramic material plate A ₁ The side surface electrode film 5b in the electrode film 5 is formed by applying a conductive paste on the side surface and drying and baking, and finally, each two-row ceramic material plate A ₁ is arranged along each score line B. , Each insulating substrate 1 is manufactured in the order of breaking. [Problems to be Solved by the Invention] And, in the manufacturing method of the invention of the prior application, the number of insulating substrates that can be manufactured by one ceramic material plate is the number arranged in one row, integrally with each other. Since the number of connected two-row ceramic materials and the value multiplied by double the number, the number of insulating substrates that can be manufactured by one ceramic material plate can be expressed in other words without increasing the number of rows arranged in one row. Then, the length in the column direction can be dramatically increased without increasing, and as a result, the cost required for manufacturing the insulating substrate can be significantly reduced.

However, on the other hand, when forming the upper surface electrode film 5a and the lower surface electrode film 5c of the electrode film 5 on each insulating substrate 1, a conductive paste is printed on the upper surface and the lower surface of the ceramic material plate A. Of the conductive paste for the upper surface electrode film 5a and the conductive paste for the lower surface electrode film 5c, the ceramic material plate A
The left and right side surfaces A of the ceramic material plate A are covered by the conductive paste in the portions adjacent to the left and right side surfaces Aa, Ab until the conductive paste solidifies by drying.
Since it will droop toward a and Ab, if the method of the above-mentioned prior invention is used ,. The ceramic material plate A is provided with the upper electrode film 5a.
When the conductive paste for coating is transferred to the next drying step or the like, and when the conductive paste for the lower surface electrode film 5c is applied thereto and then transferred to the next drying step or the like, The paste dripped on the left and right side surfaces Aa and Ab of the ceramic material plate A adheres to the transfer means for transferring the ceramic material plate A and significantly hinders the transfer. Inability to transfer occurs, or the ceramic material plate A is cracked. ． As described above, the left and right side surfaces A of the ceramic material plate A
The paste dripped on a and Ab becomes a part of the side surface electrode film 5b in the electrode film 5 of each insulating substrate 1, and the thickness dimension of the side surface electrode film 5b in the electrode film 5 of each insulating substrate 1 is large. Since the insulating substrates 1 are uneven, the dimensional accuracy of the product is significantly reduced. There was a problem to say.

An object of the present invention is to provide a method for manufacturing an insulating substrate that solves the above problems in the prior invention.

[0009]

In order to achieve this technical object, the present invention provides a two-row ceramic in which a large number of insulating substrates are arranged in two rows so that the electrode projections on each insulating substrate face outward. A plurality of material plates are integrally connected at the electrode projections of each insulating substrate of these two-row ceramic material plates to form one ceramic material plate, and each insulating substrate of the ceramic material plates is formed. After forming the upper surface electrode film, the lower surface electrode film and the resistance film at the location of, and then breaking the ceramic material plate into the double row ceramic material plate, at the location of each insulating substrate in the double row ceramic material plate. In forming the side surface electrode film, as the ceramic material substrate, the left and right side surfaces in the column direction of each insulating substrate are preliminarily provided with a blank portion having an appropriate width and a break line for break. And using those connected integrally with, the two margin portions, decided to break after the formation of the upper electrode film and the lower electrode film.

[0010]

[Operation] With this structure, when the upper surface and the lower surface of the ceramic material plate are coated with the conductive paste for the upper surface electrode and the conductive paste for the lower surface electrode by printing or the like, respectively. Of the conductive pace, those that are adjacent to the left and right side surfaces of the ceramic material plate should drop toward the left and right side surfaces of the ceramic material plate.
It is possible to surely prevent it by the blank portions integrally connected to the left and right side surfaces of the ceramic material plate.

[0011]

Therefore, according to the present invention, when the ceramic material plate is coated with the conductive paste for the upper surface electrode film and then transferred to the next drying step or the like, and also for the lower surface electrode film. When the conductive paste is applied and then transferred to the next drying step or the like, it is possible to reliably prevent the transfer failure or the occurrence of cracks in the ceramic material plate, on the other hand, the electrode film of each insulating substrate. The thickness dimension of the side surface electrode film can be prevented from becoming uneven in each of the plurality of insulating substrates, and the dimensional accuracy of the product can be improved.

[0012]

Embodiments of the present invention will be described below with reference to FIGS. In the figure, reference numeral A indicates one ceramic material plate, and as shown in FIG. 4, the ceramic material plate A is provided with a large number of insulating substrates 1 as in the case of the prior invention.
Three of the two-row ceramic material plates A1 which are arranged in two rows so that the electrode projections 4 on each of the insulating substrates 1 face outward. Of the electrode projection 4 are integrally connected to each other, and the marginal ear pieces A ₂ and A ₃ are integrally connected to both ends thereof, and the insulating substrate 1
And the margin lines B ₁ for break are provided between each other and between each insulating substrate 1 and both margin tabs A ₂ and A _3, and the width dimension is appropriately set on the left and right side surfaces thereof. The blank portions A ₄ and A ₅ of W are integrally connected to each other through the break line B ₂ to form a rectangular shape having a length dimension L and a width dimension S ₀ .

With the lower surface of the ceramic material plate A facing upward, a conductive paste forming a lower surface electrode film 5c is screen-printed on the electrode projections 4 of each insulating substrate 1 as shown in FIG. The lower surface electrode film 5c of the electrode film 5 is formed by applying the film by means such as a coating method, drying it, and then baking it. Then, the ceramic material plate A
With the upper surface thereof facing upward, at the location of the electrode projection 4 on each insulating substrate 1, as shown in FIG.
The conductive film forming a is applied by screen printing or the like, dried, and then baked to form the electrode film 5.
To form the upper electrode electrode film 5a.

After these steps are completed, the paste forming the resistance film 3 is applied in an arc shape by screen printing or the like on the upper surface of the ceramic material plate A on each insulating substrate 1 as shown in FIG. The arc-shaped resistance film 3 is formed by baking after drying, drying and baking. Then, as shown in FIG. 8, the ceramic material plate A is broken along the score lines B ₁ for each of the three double-row ceramic material plates A ₁ , and the ceramic material plate A is formed on both left and right sides of the ceramic material plate A. Both margins A ₄ and A ₅ are excised by graying along the crease line B ₂ .

Next, each of the two-row ceramic material plate A ₁
The side surface electrode film 5b in the electrode film 5 is formed by applying the conductive paste forming the side surface electrode film 5b to the side surface of the tip end portion of the protrusion 4 in each insulating substrate 1, drying and baking. , Each two-row ceramic material plate A
₁ is broken along each line B ₁ for each insulating substrate 1 as shown in FIG.

In the above-mentioned manufacturing method, the lower surface electrode film 5c is formed by applying a conductive paste, drying and firing with the lower surface of the ceramic material plate A facing upward, while the lower surface of the ceramic material plate A is formed. With the upper surface facing upward, the upper surface electrode film 5a is formed by applying, drying and firing a conductive paste, and then the paste for the resistance film 3 is applied and dried on the upper surface of the ceramic material plate A. The two-row ceramic material plate A ₁ and both margins A ₄ and A ₅ are grayed, a conductive paste for the side surface electrode film 5b is applied and dried, and then the resistance film 3 and the side surface electrode film 5b are simultaneously fired. It may be configured as follows. By doing this,
The firing process can be reduced only once.

[Brief description of drawings]

FIG. 1 is a plan view of a chip variable resistor.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged perspective view of an insulating substrate used for a chip type variable resistor.

FIG. 4 is a plan view of a ceramic material plate according to an embodiment of the present invention.

5 is a plan view of a lower surface electrode film formed on the lower surface of the ceramic material plate of FIG. 4. FIG.

FIG. 6 is a plan view when an upper surface electrode film is formed on the upper surface of the ceramic material plate of FIG.

FIG. 7 is a plan view when a resistance film is formed on the upper surface of the ceramic material plate of FIG.

FIG. 8 is a plan view when the ceramic material plate of FIG. 4 is broken.

FIG. 9 is a plan view of a ceramic material plate used in a conventional method.

FIG. 10 is a plan view when a lower surface electrode film is formed on the lower surface of the ceramic material plate of FIG.

11 is a plan view of the ceramic material plate of FIG. 9 with an upper surface electrode film and a resistance film formed on the upper surface thereof.

FIG. 12 is a plan view when the ceramic material plate of FIG. 9 is broken.

[Explanation of symbols]

A Ceramic material plate A ₁ Double-row ceramic material plate A ₄ , A ₅ Margins B ₁ , B ₂ Break line 1 Insulating substrate 2 Center hole 3 Resistive film 4 Electrode protrusion 5 Electrode film 5a Top electrode film 5c Bottom electrode Membrane 5b Side electrode membrane

Claims (1)

[Claims] 1. A plurality of two-row ceramic material plates, which are formed by arranging a large number of insulating substrates in two rows so that the electrode projections on each of the insulating substrates face outward, and insulating the two-row ceramic material plates from each other. One ceramic material plate is formed so as to be integrally connected at the electrode projections on the substrate, and an upper surface electrode film, a lower surface electrode film, and a resistance film are formed on the insulating substrate parts of this ceramic material plate. Then, after breaking this ceramic material plate into the two-row ceramic material plate, and forming a side surface electrode film at the location of each insulating substrate in this two-row ceramic material plate, On both the left and right side surfaces of the insulating substrate in the row direction, blanks of an appropriate width are integrally connected in advance through a break line, and both blanks are Chip variable resistor dexterity insulating substrate manufacturing method characterized by break after the formation of the surface electrode film and the lower electrode film.