Planar inductor

【0001】

[Technical field to which the invention belongs]

The present invention relates to a planar inductor comprising at least one spiral coil placed on a flat carrier and a coated ferromagnetic material placed on the carrier.

【0002】

[Conventional technology]

From German Publication No. 2441317, a method of adjusting the inductance of a flat coil manufactured by thin film technology is known. In this method, most or a small portion of the flat coil is coated with a paste composed of a magnetizable powder mixed with a binder, depending on the deviation of the actual inductance value from the set inductance value. The thickness of the paste to be or coated is increased. In order to adjust the inductance of the flat coil, a part of the coil surface defined by the angle of application is covered with paste. The angle of application is linearly related to the change in inductance, but the thickness of the paste has a non-linear effect on the change in inductance. The above specification describes that the process of adjusting the inductance can be automated by coating a flat coil with paste.

【0003】

European Patent Application No. 310396 discloses a planar inductor having a spiral conductor coil sandwiched between ferromagnetic layers by an intervening insulating layer. The spiral conductor coil forms two coils of the same outer shape arranged close to each other on the same plane. Further, since these two spiral coils are electrically connected to each other, currents in different directions flow through the individual coils. Also, the ferromagnetic layer has a surface larger than the sum of the surfaces of the two conductor coils. Such a device prevents a decrease in inductance when the individual elements are integrally coupled, and increases the inductance value per unit volume.

【0004】

[Problems to be Solved by the Invention]

However, the inductors described above are relatively complexly constructed of a large number of layers or rectangular insulating materials or ferromagnetic elements. On the other hand, this significantly increases the cost of manufacturing, and neither changes nor adjustments can be made to the magnetic coupling during manufacturing.

【0005】

An object of the present invention is to accurately adjust or set the inductance value during manufacturing in a simple manner and / or to set the magnetic coupling of each of the plurality of coils or windings of the inductor accordingly easily and accurately. It is to provide a planar inductor.

【0006】

[Means for solving problems]

This object is achieved by the type of planar inductor described at the outset, which is configured to place a ferromagnetic material inside an insulating window secured to the carrier on the carrier during the coating process.

【0007】

The planar inductor of the type according to the invention can be suitably used in hybrid technology or multi-chip modular technology in which a plurality of electronic elements capable of forming an integrated circuit are arranged on a planar carrier such as a PC board. The planar carrier preferably has a conductive layer cut out into a line structure predetermined by an etching technique. These (conductive) line structures are used for the electrical connection of elements placed on the carrier. In addition, from these line structures, planar inductors manufactured in a simple, accurate and robust manner can be suitably formed. In order to mechanically protect such a planar carrier accommodating the element, a protective layer is finally arranged in a so-called coating process, the protective layer being a cured coating material that encloses the element and their connecting wires. Consists of.

【0008】

If only a predetermined range of the carrier accommodates the device in a particular embodiment of an electronic circuit manufactured in this way, the device if the other range of the carrier has a line structure (printed line). It is advantageous to cover only the range of carriers that contain the coating material. Before defining and providing this coating material, first, an insulating window is provided, for example, by being attached onto a carrier, and the window surrounds an element accommodating range on the surface of the carrier like a frame. During this coating process, a coating material is provided inside these insulating windows.

【0009】

In the case of the planar inductor according to the present invention, insulating windows are also provided on one or more coils, respectively. This window surrounds the entire planar inductor, but only partially overlaps the planar inductor. The heights of the insulating windows perpendicular to the surface of the carrier can be selected differently from each other, and for this reason the heights that are also preferably used for coating other devices are used. As a result, simplification and uniformity during production is achieved. As a result of the size of the insulated window parallel to the surface of the carrier, and as a result of the positioning of the insulated window on most or a small portion of the entire surface of the carrier covered by the planar inductor, the inductance value, i.e., the plurality of planar inductors. Couplings between the coils of are set respectively. The insulated window is filled with a ferromagnetic material during the coating process. In principle, the same manufacturing steps and methods used to coat the device greatly simplify manufacturing. Also, almost the same coating material is used, and only ferromagnets added to this material are used to increase the magnetic coupling or inductance value, respectively. In this way, the ferromagnetic material can be obtained from the coating, also called the coating material, in a very simple way, and at the same time, the mixing ratio of the ferromagnetic material added to the coating material and each insulating window. The amount of material provided is selected to set the coupling or inductance, respectively. Preferably, these parameters fix the dimensions, shape and position of the insulating window and the composition of the ferromagnetic material to preset values for the particular planar inductor to be manufactured. By adding a predetermined amount of ferromagnetic material when placed on the carrier in the insulated window, the inductance or coupling can be set to exactly the desired values, respectively, and the ferromagnetic material is placed. In the meantime, the electrical measurements are adjusted. Insulated windows allow for very good mechanical control of the manufacturing process, i.e., very precise tolerance is achieved at a small cost.

【0010】

The dependent terms of the claims show a preferred example of the planar inductor according to the present invention.

【0011】

By an example of a planar inductor according to the invention, the bridge magnetic material can simultaneously provide mechanical protection of the line structure, especially the connecting wire, especially if at least one coil is completely covered. Since the ferromagnetic material is preferably non-conductive, this material can cover not only the planar inductor but also the electronic components adjacent to it as mechanical protection during one operation. The effect of the ferromagnetic material on the line structure and its transmission property should be considered accordingly.

【0012】

Currently known coating materials (coating materials) and ferromagnetic additives, in the case of the invariant compact wire structure of the type of planar inductor of the invention, improve the quality of inductance, i.e. magnetic coupling or setting the inductance value. In addition to the increase in particular, it is also possible to improve the ratio of the inductance value to the ohmic resistance of the linear structure. For example, when used in a frequency selection circuit for communication technology, this improves the transmission characteristics of the circuit.

【0013】

BEST MODE FOR CARRYING OUT THE INVENTION

These and other aspects of the invention will be described with reference to the examples described below.

【0014】

In the schematic representation shown in FIG. 1, reference numerals indicate details of the planar carrier as is preferably used in hybrid or multi-chip modular technologies. The planer carrier is provided with two planers, in particular spiral coils 2 and 3 suitably arranged on the planer carrier in the form of a so-called print line structure. The coupling wires 4 and 5 form a connecting bridge between the terminal regions 6, 7 and 8, 9 respectively, and thus the end of the coil in the center of the helix and the line structures 10 and 11 located outside the helix. Establish a conductive connection line with each of the. The planar carrier 1 also supports another element, which is also an integrated circuit (not shown in FIG. 1) in the shape of a scattered semiconductor body, and the electrical connections of that element are in the line structure of coils 2 and 3, respectively. It is established through the corresponding line structures, i.e., line structures 10, 11 and is manufactured in the same manufacturing process.

【0015】

The planar carrier 1 houses an insulating window 12 (partially covering coils 2 and 3), which is attached to the planar carrier 1. The attachment of the insulated window 12 may preferably be included in the manufacturing process of the other element (not shown). A portion of the surface of the planar carrier 1 surrounded by the insulating window 12 is coated with a ferromagnetic material 13, i.e. a mixture of a coating material that is liquid and in-situ cured to the insulating window and a ferromagnetic additive. Will be done.

【0016】

FIG. 2 shows a planar inductor on a flat carrier in longitudinal section along line ZZ. Also, this representation indicates the thickness of the material only in a diagrammatic way in particular.

【0017】

In the embodiment shown in FIG. 2, the ferromagnetic material 13 covers only a part of the planar inductor, and in particular, the coupling wires 4 and 5 are not protected. For its mechanical protection, it is advantageous to form the insulating window 12 so that the entire planar inductor with the associated coupling and connecting wires is surrounded as much as possible and covered with a ferromagnetic material. Such a device is shown in FIG. 3, for example, in a plan view selected for deformation by alternating spiral coils. In this figure, the first coil 20 between the terminal regions A and B surrounds the second coil 21 between the terminal regions C and D. Coupling wires 22, 23 connect terminal regions B, C, and D to line structure 24, respectively, and place the inner coil wire of the planar inductor outside the circuit (not shown in FIG. 3) present on the planar carrier 1. Connect to the parts. The ferromagnetic material 13 covers the entire planar inductor.

【0018】

In particular, in the embodiment shown in FIG. 3, the arrangement of coils 20 and 21 can be used for different functions or sizes. By changing only the coupling wires 22, 23 and the first coil 20 or the second coil 21 accordingly, a series combination of the coils 20, 21 wound in the same direction, or the opposite of the coils 20, 21 The wound series combination allows the desired inductor to be formed at will. The invariant geometry of planar inductors allows the desired inductor to obtain different sizes only with differently guided coupling wires for different applications, resulting in even greater inductance. The value appears with the ferromagnetic material. The arrangement of the coupling wires 22, 23 shown in FIG. 3 shows another possibility of connecting the coils 20, 21, that is, a transformer. Preferably, the terminal regions A to D are individually connected to an external element, particularly an electronic switch in which these different interconnects are selectively realized.

【0019】

The examples shown in this drawing can be modified in many ways. For example, another line structure or element can be placed on the back surface of the planar carrier 1. It is also possible to use a flat carrier having a multi-layer structure of a line structure alternately arranged with an insulating layer. The surface of the planar carrier 1 on the outside of the insulating window 12 can be coated with a coating agent or a coating material containing no ferromagnetic additive, respectively. At the very least, even complex circuit devices can be manufactured with a simple manufacturing process. Since the manufacture and adjustment of the planar inductor according to the present invention is carried out in the normal manufacturing process of the hybrid technology or the multi-chip modular technology, respectively, in addition to the manufacturing equipment already used in the hybrid technology or the multi-chip modular technology, another machine. , No equipment or utensils required.

[Simple explanation of drawings]

FIG. 1 is a plan view showing a first embodiment of a planar inductor according to the present invention.

FIG. 2 shows a cross-sectional view across line ZZ of the planar inductor shown in FIG.

FIG. 3 shows a second embodiment of a planar inductor according to the present invention in a plan view.

[Explanation of symbols]

1 Planer carrier 2,3 Spiral coil 4,5 Coupling wire 6,7,8,9 Terminal area 10, 11 Wire structure 12 Insulated window 13 Ferromagnetic material 20,21 Coil 22, 23 Coupling wire 24 Wire structure A to D terminals region