JPS58100413A - Thick film condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to thick film capacitors.

One type of thick film capacitor is a capacitor having a structure shown in FIGS. 1 to 3. This capacitor is provided with a lower conductor layer 2v on the upper surface of an insulating substrate l made of ceramic, and a dielectric layer 3 made of ceramic on this lower conductor layer 2. The upper conductor layer 4 is sequentially laminated and formed, and the entire structure is further covered with an insulating coating film 5. Note that a narrow lead-out portion 6.7 extends from the lower-upper conductor layer 2.4, and an electrode 8.9 is formed at the tip thereof. Electrode 8
Parts of the box 9 and the drawer parts 6 and 7 are coated with the coating film 5.
It protrudes from and is exposed on the insulating substrate l.

Incidentally, in a capacitor having such a structure, the upper and lower conductor layers 4 and 2 forming the capacitor have the same rectangular pattern. For this reason, a leakage electric field (indicated by the arrow in FIG. 2) from around the electrode is generated in a portion of the coating film 5. Since the coating film 5 is generally made of glass or the like, its dielectric constant is large. As a result, the capacitor's current area increases and the capacitance value differs from the designed value.

Furthermore, the capacitance value varies depending on the thickness of the coating film 5 or the booting material.

Therefore, an object of the present invention is to provide a thick film capacitor with a stable capacitance value.

In order to achieve such an object, the present invention includes an insulating substrate, a lower conductor layer provided on the insulating substrate, a dielectric layer covering the lower conductor layer, and a lower conductor layer provided on the dielectric layer. an upper conductor layer provided to face the upper conductor layer; an insulating coating film covering the upper conductor layer;
and an exposed electrode extending from a lower conductor layer onto an insulating substrate.The present invention will be described below with reference to Examples.

4 to 6 are diagrams showing a thick film capacitor according to an embodiment of the present invention, in which FIG. 4 is a plan view and iris 5 is a
FIG. 6 is a cross-sectional view taken along the line ■--v in the figure, and FIG. 6 is a cross-sectional view taken along the line ■--■ in FIG. This thick film capacitor is also similar to the conventional thick film capacitor shown in FIG. A dielectric layer 3 made of ceramic on the conductor layer 2. Electrode 9K via lead-out part 7
The upper conductor layer 4vl is then laminated, and an insulating coating film 5 covers at least the portions other than the electrodes 8.9v. In addition, in this embodiment, the fourth
As shown in the figure and FIG. 5, the lower conductor layer 2 located directly below the upper conductor layer 4 is formed smaller than the upper conductor layer 4, and the periphery of the lower conductor layer 20 is smaller than the periphery of the upper conductor layer 40. Peng is located inside the tree. Furthermore, by bending the peripheral portion of the upper conductor layer 4 downward, the effect of preventing electrical scale leakage is enhanced.

In a thick film capacitor having such a structure, the electric field between the peripheries of the upper and lower conductor layers 4.2 is larger in the upper conductor layer 4 than in the lower conductor layer 2, as shown by the arrow in FIG.
The range of the electric field is determined by the size of the upper conductor layer 4, is within the dielectric layer 3, and does not leak into the outer coating film 5. Further, the effective area that determines the capacitance of the capacitor is the area of the lower conductor layer 20. Therefore, the capacitance value of this thick film capacitor is stable without varying depending on the thickness and material of the coating film 5 as in the past, and is warmed to show the value W according to the designed value. Not limited to examples.

For example, as shown in FIG. 7, the electric field leakage prevention effect can be further enhanced by bending the entire local portion of the upper conductor layer 40 so as to contact the surface of the substrate l so as to wrap it around the lower conductor layer 2v. can.

In this case, wiring is drawn out from the lower conductor layer 2 through a wiring layer (not shown) formed within the substrate l.

As described above, according to the present invention, it is possible to provide a stable thick film capacitor whose capacitance value is a designed value.

[Brief explanation of the drawing]

Stripe 1 is a plan view showing a conventional thick film capacitor;
3 and 3 are cross-sectional views taken along line T and 1-1 in FIG. 1, FIG. 4 is a plan view of a thick film capacitor according to an embodiment of the present invention, and FIGS. 5 and 6. is ■-v in Figure 4
FIG. 7 is a sectional view showing another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Insulating substrate, 2... Lower conductor layer, 3... Dielectric, 4... Upper conductor layer, 5... Coating film,
8, 9... Electrode.

Claims (1)

[Claims] 1. An insulating substrate, a lower conductor layer provided on the insulating substrate, a dielectric layer covering the lower conductor layer, and a dielectric layer on the dielectric layer facing the lower conductor layer. A thick film capacitor comprising an upper conductor layer provided in the upper conductor layer, an insulating film covering the upper conductor layer, and exposed electrodes extending from the upper and lower conductor layers to the insulating substrate, wherein the surface of the upper conductor layer is 2. The thick film capacitor according to claim 1, wherein the peripheral portion of the upper conductor layer is bent downward.