DE1614429B2 - STACKED CAPACITOR THAT CAN BE ADJUSTED TO A DESIRED SET POINT OF ITS CAPACITY - Google Patents

Description

The invention relates to a stacked capacitor, which is to a desired value of its Capacity is adjustable. Stacked capacitors in the context of the present invention consist of stacked capacitors Layers of dielectric material and metal layers that are located between the layers and serve as capacitor layers, which alternately from layer to layer on different sides of the stack out of this and are electrically connected to one another there. Layers electrically interconnected with one another The capacitor assignments represent the same potential. It is possible to connect to the interconnection area these layers also to attach an external power supply, z. B. to solder to the stack capacitors to connect with other electrical components. The stacked capacitors can can also be plugged in, with additional external power supply lines not being required.

Stacked capacitors of the type described are e.g.

ίο knows; there are also so-called multiple capacitors described in stack construction, in which between several main coverings that lead to an interconnection side are performed, each several, z. B. three, secondary coatings inserted as counter electrodes, led to another interconnection side and there with the corresponding number of power supply lines are provided. In the known stacked capacitors, the achievement of a desired capacitance prepares Difficulties insofar as the size of the capacitor assignments is usually predetermined are so that the capacity, among other conditions, depends on the sum of the opposing Area parts of the metallic layers is dependent. With sufficient care it leaves set up that the desired size of the capacitance co-determining area of the opposite Metal layer parts is reached; however, is the desired capacitance value of the stacked capacitor then still not to be reached with sufficient certainty, because, as is well known, The thickness of the dielectrically effective layers also influences the capacitance. Especially with stacked capacitors with extremely thin dielectric layers, manufacturing-related fluctuations act the layer thickness in mostly considerable and hardly controllable scatter of the capacity of the finished capacitor up to 20%. An adjustment is possible by grinding.

The present invention is based on the object To indicate ways and means with the help of which these manufacturing-related spreads of the final capacity of the capacitor can be compensated.

In order to achieve this object, the stack capacitor described at the beginning is characterized according to the invention characterized in that on at least one of the two outer dielectric layers for Filled with conductive material forming free fields, grid-like associated conductor tracks are applied, which are electrically conductively connected to one another and to an interconnection side of the stack are guided.

This gives you the option of using a stacked capacitor on at least one of the external capacitors dielectrically effective layer by filling in the existing between the conductor tracks free areas increase the capacity by a series of small amounts to approach the desired target value. the The capacitance of the stack capacitor that has not yet been balanced must of course be one have an amount below the desired target value. But it does not cause any problems, capacitor stacks with a lower than the desired capacity.

The advantage of balancing in this way is particularly evident with stacked capacitors, in which the dielectric layer consists of ceramic and in particular of so-called NDK ceramic.

3 4

Under "NDK ceramic" in this sense is a measure and capacitors that have an output value of to understand material, whose dielectric constant have 7300 to 7840 pF, on an outer surface with is at most a few hundred, preferably provided under grid grids. These are then with the 100 lies. These NDK masses are connected to a special electrode, the tincture otherwise by having a low dependency 5 is burned in, and the capacity is again the dielectric constant measured from the temperature. Which have by printing a grid and / or whose dependency on the templating (FIG. 3) is the additional capacity temperature is almost linear. about 350 pF. Now the twelve or six un-

It is therefore particularly advantageous to use the printed fields in the grid grids depending on

the invention proposed compensation possibility io difference to the nominal capacity with silver suspension

in the case of stacked capacitors made of NDK ceramics, this must be filled out. Each field increases the capacity

turn around. The ones used as capacitors are around 50 pF. The setpoint can thus be sufficient

As is known per se, metal layers consist of precisely adjusted.

Palladium and are used before the sintering of the ceramic. The invention and

see stacked capacitor on the provided in foil form. Further details of the same are to be explained in more detail

applied lying ceramic mass. will.

The grid from the conductor tracks consists of F i g. 1 shows a stacked capacitor in section

partly made of stoved silver. Burn-in silver is shown along the line I-I in FIG. 2;

one remaining after the baking process, over- F i g. 2 shows the stacked capacitor in plan view;

predominantly made of silver layer, which thereby 20 * Fig. 3 shows a lattice-shaped conductor track

arises that on the ceramic body a coating order approximately natural size, while in the

in the form of a per se known silver particle, FIGS. 1 and 2 show the size ratios for reasons j |

Adhesive oxides and suspensions containing glass powder are shown distorted for the explanation. The j |

with organic components (nitrocellulose, dissolved stack capacitor is opposite its length L and j |

in ethylene glycol monoethyl ether) as a suspension - 25 its width B (Fig. 2) only of small thickness D \

medium applied (screen printing, spraying, etc.) and at (Fig. 1). The dimensions are in the real! '

Temperatures between 500 and 850 ° C burn-in, for example L = 15 mm, B - 10 mm and |

will. The suspension mentioned is usually also D = 1 mm. j

already referred to as "burn-in silver". The stack capacitor according to FIG. 1 consists of; ■

To produce a ceramic stacked capacitor 30 several layers 1 of dielectrically effective % sators according to the invention, unfired material. The body is interspersed with thin layers of metal 2 and 3 covered with palladium, with the metal layers 2 on the ceramic mass-filled, film-forming, narrow face with the silver layer 4 and the materials for achieving the desired arrangement of metal layers 3 on the other narrow ends of the capacitor linings stacked on top of one another, and the surface with the silver layer 5 to which the condens the conductor tracks (the grid) are connected to the parts representing the capacitor linings, the outer layer is on before the stack is sintered. The silver layers 4 and 5 can carry currents. Feeds to be soldered. On the outside

Advantageously, however, the conductor tracks are dielectric layers (top and bottom) j

40 grid grids 6 and 7 are applied to the fully sintered capacitor stack. i

wear. In Fig. 2 the plan view shows the upper di- |

electrical layer 1, the comparable with the screen grid 6 \

Embodiment can be seen, which is electrically connected to the silver layer 5 j:

connected. The free fields 8, which are from j

For capacitors formed from a mass with a 45 grid grid 6, serve for the purpose of j.

ε value of around 50 with a nominal capacity of 8000 pF will increase the capacity until the target value is reached. the

the fourteen ceramic layers of about 70 μπι dashed lines in the two left fields should be!;

Thickness used. The stacks made from it indicate that metal has been applied there, whereby the j

the dimensions of about 15 X 10 X 1 mm ³ . The after the manufacture of the stack capacitor before [;

Capacity values then initially spread over a desired value due to the underlying capacity;

different thickness of the foils and imprecise stacking. The area covered by conductor tracks

from 6800 to 8000 pF. A capacitance is roughly equivalent to an outer dielectric layer

If a tolerance of ± 2% is required, the condensate of the total area of the ab- j

Sators with capacitance values that are too low create a locking surface of this layer. This ensures

Grid - as shown in Fig. 3 - made of silver 55 both that there are still enough open adjustment surfaces

Suspension (stoving silver = in organic sus- are present as well as that from the contact side j

Particles of silver distributed over pension funds, remotely bonded conductor track parts low-ohmic j

oxides and lead-boron-silicate glass). There are closed, whereby the loss angle of the con-;

become capacitors, which an output capacitor is not impaired. ;

value of 6800 to 7300 pF, on both sides 60 Fig. 3 shows a grid in natural size. :

1 sheet of drawings

Claims (6)

Patent claims: 1. Stacked capacitor, which can be adjusted to a desired setpoint of its capacitance, consisting of stacked layers of dielectric material and between the Layers located, serving as capacitor layers metal layers, which alternate from Layer to layer on different sides of the stack led out of this and there with one another are electrically connected, characterized in that at least one the two outer dielectric layers (1) to be filled with conductive material Conductor tracks (grid 6, 7) which are assigned to one another in a grid-like manner and form free fields (8) are applied which are connected to one another in an electrically conductive manner and to a connection side (4, S) of the stack are guided. 2. Stacked capacitor according to claim 1, characterized in that the dielectric layers (1) are made of ceramic. 3. Stacked capacitor according to claim 2, characterized in that the dielectric layers (1) consist of ceramics with a low dielectric constant, their change depending on on the temperature is low and / or is linear. 4. Stacked capacitor according to one of the preceding claims, characterized in that that the conductor tracks (6,7) attached to at least one outer dielectric layer (1) consist of stoved silver. 5. A method for producing a stacked capacitor according to any one of the preceding claims, in the still unfired, thin layers of film-forming, filled with ceramic mass, covered with palladium as coverings Plastics stacked on top of each other to achieve the desired arrangement of the capacitor plates and this stack is subjected to sintering, characterized in that the conductor tracks (the grid 6, 7) on the outer layer (1) before sintering the stack be applied. 6. A method for producing a stacked capacitor according to any one of claims 1 to 4, characterized characterized in that the conductor tracks (6,7) are applied to the fully sintered capacitor stack will.