JPS6225873Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a chip-type porcelain capacitor.

Chip-type ceramic capacitors are easy to make small and large in capacity, can be bonded to a flat conductive pattern and meet the demands for high-density packaging, exhibit excellent frequency characteristics up to a high frequency range, and have a small external shape. It has excellent features such as being standardized, allowing automatic mounting and assembly when mounted on printed circuit boards, and being suitable for mass production. Alternatively, demand is rapidly expanding as electronic/electrical devices such as electronic tuners become more sophisticated and become more densely packaged.

1A and 1B show an example of a chip-type ceramic capacitor, in which an electrode 2 is provided on one surface 1a of a flat dielectric ceramic 1 whose main component is barium titanate or titanium oxide, etc. For example, through a dielectric ceramic layer 1A having a layer thickness of about 20μ,
Embed the internal electrode 3, and make the internal electrode 3 50 to 100μ.
It has a structure in which it is backed and reinforced by a dielectric ceramic layer 1B. Opposite edges of the electrodes 2 and 3 are end electrodes 4 and 5 provided on both sides of the dielectric ceramic 1.
The surface of the electrode 2 is coated with a protective layer 6 made of a glass layer or synthetic resin to ensure insulation and chemical resistance against solder flux.

In the chip-type ceramic capacitor described above, the dielectric ceramic layer 1A between the surface electrode 2 and the internal electrode 3 provides substantial capacitance.
A is formed to have a very thin layer thickness, for example, about 20 μm, in order to achieve a small size and a large capacity, and its mechanical strength is insufficient. Therefore, the lack of mechanical strength of the dielectric ceramic layer 1A is compensated for by the dielectric ceramic layer 1B provided lining the internal electrodes 3. The dielectric ceramic layer 1B is made of the same ceramic as the dielectric ceramic layer 1A, for example, a ceramic whose main component is barium titanate or titanium oxide.

However, even if the dielectric ceramic layer 1B increases the mechanical strength, it does not necessarily increase the capacitance as a magnetic capacitor. , not desirable.

The object of the present invention is to solve the above-mentioned problems and to provide a small, large-capacity chip-type porcelain capacitor whose capacity can be doubled by only a slight increase in thickness.

In order to achieve the above object, the chip-shaped ceramic capacitor according to the present invention is provided with two capacitor parts each consisting of a surface electrode and an internal electrode on both sides in the thickness direction of a flat dielectric ceramic. A reinforcing layer made of dielectric ceramic, which is thicker than the dielectric ceramic layer formed between the surface electrode and the internal electrode, is provided between each internal electrode of the two capacitor parts, and the surface electrode of the two capacitor parts and The internal electrodes are conductively connected to end electrodes provided at both ends of the dielectric ceramic so that the two capacitor parts are connected in parallel, and the A notch is provided that narrows the width of the dielectric porcelain toward the tip in the length direction, and both ends of the dielectric porcelain are formed at both ends of the dielectric porcelain in the width direction. It is characterized in that the end electrode is formed so as to be located inside the surface.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The content of the present invention will be explained in detail below with reference to the accompanying drawings which are examples. Fig. 2 is a plan view of a chip-shaped ceramic capacitor according to the present invention, and Fig. 3 is a plan view of the chip-shaped porcelain capacitor according to the present invention.
FIG. 3 is a cross-sectional view taken along line A ₁ -A ₁ . In this embodiment, both surfaces 7a and 7 of a flat dielectric ceramic 7 whose main component is barium titanate or titanium oxide, etc.
On the b side, capacitor portions C ₁ and C 2 consisting of a surface electrode 8 or 9 and an internal electrode 10 or ₁₁ are provided, and a surface electrode is provided between the internal electrodes 10 and 11 of the two capacitor portions C ₁ and C ₂ . A reinforcing layer 7C made of dielectric ceramic which is thicker than the dielectric ceramic layer 7A (or 7B) between the inner electrode 8 (or 9) and the internal electrode 10 (or 11) is provided.

The surface electrodes 8, 9 and the internal electrodes 10, 11
is made of a noble metal with a high melting point that can withstand a firing temperature of 1,100 to 1,400°C, such as a platinum-palladium-based electrode material. These electrodes 8 to 11 are
In order to constitute capacitor parts C ₁ and C ₂ whose capacitors are dielectric ceramic layers 7A and 7B, one edge thereof is formed by applying silver paste on both ends of dielectric ceramic layer 7 with a brush or the like. 12 and 13 are individually electrically connected. In this embodiment, the surface electrode 8 constituting the capacitor portion C ₁ and the internal electrode 11 constituting the capacitor portion C ₂ are used as the end electrode 12, and the surface electrode 9 constituting the capacitor portion C ₂ and the capacitor portion C ₁ are used as the end electrode 12. Internal electrodes 10 constituting the structure are connected to end electrodes 13, respectively. Therefore, this embodiment has an equivalent circuit as shown in FIG. 4 in which capacitor portions C ₁ and C ₂ are connected in parallel between end electrodes 12 and 13, and the capacitance is approximately twice that of the conventional circuit.

Further, the reinforcing layer 7C composed of the dielectric ceramic layer between the internal electrodes 10 and 11 is formed by the dielectric ceramic layer 7.
A layer thickness thicker than that of 7B (for example, 20μ),
For example, the layer thickness is about 50 to 100 μm.
By setting the layer thickness to such a value, the mechanical strength of the chip-shaped ceramic capacitor can be sufficiently increased.

Moreover, compared to the conventional chip-type porcelain capacitor shown in Fig. 1, the capacitor part _C2 is
Only a layer thickness of about 20μ is added, and the increase in the overall layer thickness is negligible.

Therefore, according to the present invention, it is possible to provide a chip-shaped porcelain capacitor that is small in size, has a large capacity, and has high mechanical strength.

Furthermore, arc-shaped missing portions 15 to 18 are provided at the four corners of both ends of the dielectric ceramic 7 in the length direction to make the dielectric ceramic 7 narrower toward the tip in the length direction. The end electrodes 8 and 10 have missing parts 15 to 18
The dielectric ceramic 7 is formed in the narrow portion so that both end portions in the width direction are located inside both end surfaces of the dielectric ceramic 7 in the width direction. Missing portion 15 as described above
.about.18, both ends in the width direction where the silver paste coating thickness tends to increase are cut out from the missing portions 15 to 1.
8, it is cut off. Moreover, the end electrodes 12,
13, as shown in FIG.
When the ceramic capacitors are arranged in the width direction, both ends of the end electrodes 12 and 13 in the width direction enter inside the contact position of the capacitor, and the end electrodes 12 and
The influence of the coating thickness of No. 13 is eliminated.

In addition, the end electrodes 12 of adjacent ceramic capacitors
A gap _g1 is formed between both ends of the electrodes 12-12, 13-13 in the width direction, and the end electrodes 12-12, 13-1
3 are in a non-contact state with each other, it becomes possible to measure characteristics such as capacitance while they are arranged as shown in FIG. 5, and the characteristic measurement work becomes easier.
Furthermore, as shown in FIG. 5, it is possible to mount them on a circuit board in a state where they are lined up in the width direction, thereby significantly improving the mounting density.

In the embodiments shown in FIGS. 2 and 3, the surface electrodes and internal electrodes of different capacitor parts C ₁ and C ₂ are connected to the same end electrode, but the surface electrodes and internal electrodes are connected to the same end electrode. It is also possible to connect the electrodes to the same end electrode. Also, Figures 2 and 3
In the figure, a protective layer 14 is provided on the surface of the surface electrodes 8, 9 in order to ensure the insulation properties of the surface electrodes 8, 9 and chemical resistance against soldering flux. If a magnetic capacitor is used, the protective layer 14 can be omitted and the surface electrode can be inserted between the taped leads.

As described above, the chip-type capacitor according to the present invention has two capacitor parts each consisting of a surface electrode and an internal electrode, which are provided on both sides in the thickness direction of a flat dielectric ceramic. A reinforcing layer made of dielectric ceramic, which is thicker than the dielectric ceramic layer formed between the surface electrode and the internal electrode, is provided between each internal electrode of the section, and the surface electrode and the internal electrode of the two capacitor sections are The two capacitor parts are electrically connected to end electrodes provided at both ends of the dielectric ceramic so that they are connected in parallel, and the dielectric is connected to the four corners of the dielectric ceramic at both ends. A cutout is provided in the porcelain to make it narrower toward the tip in the length direction, and in the part narrowed by the cutout, both ends in the width direction are closer to both end surfaces in the width direction of the dielectric porcelain. Since the end electrode is formed so as to be located inside, the following effects can be obtained.

(a) It has mechanical strength equivalent to or higher than that of conventional products;
Moreover, it is possible to provide a small-sized, large-capacity chip-type ceramic capacitor that can obtain more than twice the capacity of a conventional capacitor with only a slight increase in thickness.

(b) The electrical circuit is similar to that of a multilayer ceramic capacitor, but because of the reinforcing layer, it is possible to provide a chip-type ceramic capacitor with greater mechanical strength than a normal multilayer ceramic capacitor.

(c) Since the end electrodes are formed in the narrow part due to the missing part so that both ends in the width direction are located inside both end faces of the dielectric ceramic in the width direction, When ceramic capacitors are arranged in the width direction, both ends of the end electrodes in the width direction go inside the contact position of the capacitor, and there is no gap variation due to variation in the coating thickness of the end electrodes at the corners.

(d) When ceramic capacitors are lined up in contact with each other in the width direction, the end electrodes of adjacent magnetic capacitors are not in contact with each other. This makes the characteristic measurement work easier.

(e) It is possible to mount them on a circuit board in a state in which they are lined up in contact with each other in the width direction, thereby making it possible to significantly improve the mounting density.

[Brief explanation of the drawing]

FIG. 1A is a plan view of a conventional chip-shaped ceramic capacitor, FIG. 1B is a sectional view thereof, FIG. 2 is a plan view of a chip-shaped ceramic capacitor according to the present invention, and _{FIG. -A} Cross section on line 4, 4th
The figure is also an equivalent circuit diagram, and FIG. 5 is a diagram illustrating the effects of the chip-shaped ceramic capacitor according to the present invention. 7... Dielectric ceramic, 7A, 7B... Dielectric ceramic layer, 7C... Reinforcement layer, 8, 9... Surface electrode, 1
0, 11... Internal electrode, 12, 13... End electrode.

Claims (1)

[Scope of utility model registration request] Two capacitor parts constituted by a surface electrode and an internal electrode are provided on both sides in the thickness direction of a flat dielectric ceramic, and the surface electrode and the internal electrode are provided between each internal electrode of the two capacitor parts. A reinforcing layer made of dielectric ceramic is provided which is thicker than the dielectric ceramic layer formed between the two capacitor parts, and the surface electrodes and internal electrodes of the two capacitor parts are connected to the end electrodes provided at both ends of the dielectric ceramic. On the other hand, the two capacitor parts are electrically connected so that they are connected in parallel,
Further, cutout portions are provided at the four corners of both ends of the dielectric ceramic to make the dielectric ceramic narrower toward the tip in the length direction, and in the portion narrowed by the cutout portions, A chip-shaped porcelain capacitor characterized in that the end electrode is formed such that both end portions in the width direction are located inside both end surfaces in the width direction of the dielectric ceramic.