JPH0564844B2 - - Google Patents

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a thin film printed coil that can be used as a coil for a motor or a transformer, and in particular, it relates to a thin film printed coil that can be used as a coil for a motor or a transformer, and in particular, it relates to a thin film printed coil that can be used as a coil for a motor or a transformer. The present invention relates to a printed coil made of a ferromagnetic material such as iron.

``Prior Art'' Sheet-shaped printed coils, in which coils are formed by adhering a conductor such as copper foil in a spiral shape on an insulating sheet member, are currently available in various structures as coils for flat motors, etc. It is being Since these conventional printed coils are formed by etching a coil conductor such as copper into a spiral shape, they are generally used as printed coils for so-called coreless motors and the like. Printed coils of this type are also employed in various thin film impedance means.

"Problems to be Solved by the Invention" Conventional printed coils as described above generally have a structure that only has a coil part. If an etching method is used to manufacture the coil, the core will be made of the same material as the coil conductor, such as copper, at the same time. However, if the core portion is made of a good conductor such as copper, the magnetic resistance becomes high, which poses a practical problem as a core structure.

``Means for Solving the Problems'' The present invention aims to provide a flat coil to be formed on an insulating sheet, and an island-like pattern that is electrically insulated from the coil and becomes an iron core in the center using a ferromagnetic material such as iron foil. The present invention provides a printed coil configured to be formed by etching from a member, and the printed coil with such a structure is laminated in a multilayer structure, and the flat coils of each layer are connected in series, and each island pattern as an iron core part is also formed. They can be configured to be magnetically connectable to each other. The magnetic resistance of the island pattern functioning as the iron core can therefore be configured to a sufficiently low value, while the flat coil surface should be appropriately coated with a good conductor material such as copper or silver to increase conductivity. This makes it possible to construct multilayer printed coils, large-sized coils, or other finely patterned coils.

"Example" FIGS. 1 and 2 show a conceptual plan view and a cross-sectional view of a printed coil constructed according to an example of the present invention, and 1 shows various electrically insulating plastic films. It is an insulating sheet member consisting of an insulating sheet member, which has a single island-like pattern 2 serving as an iron core in the center of one side, and has an island-like pattern 2 on the outside in a state of being electrically insulated from the island-like pattern 2. A spiral flat coil 3 having a starting end 3A and a terminal end 3B is formed with a required number of turns so as to surround the coil. Such a printed coil is manufactured by placing a ferromagnetic foil member such as iron foil on an insulating sheet member 1 in advance.
A so-called flexible laminated material uniformly adhered to the iron core island pattern 2 is formed by photo-etching the material.
And the flat coil 3 can be formed at low cost and with high efficiency. The island pattern 2 and the flat coil 3 are
Of course, by using a flexible double-layered material or the like, it is possible to form a desired pattern on both the front and back surfaces of the insulating sheet member 1.

FIG. 3 shows an example of a multilayer printed coil in which a single-sided printed coil and a double-sided printed coil as described above are laminated, and the flat coil 3 and core island pattern 2 of each layer are electrically connected. Magnetic connection structure 4
For example, each flat coil 3
can be configured to be connected in series using a through-hole conductive structure using their starting end 3A and terminal end 3B, and each island-like pattern 2 can also be connected in series using through-hole conductive means or iron pins, etc. can be magnetically connected to each other.

As mentioned above, the flat coil 3 is formed of the same ferromagnetic material as the iron core island pattern 2, but
When constructing a multilayer printed coil, a large printed coil, a printed coil with high density or a fine pattern, etc., the electrical resistance of the coil becomes high, making it difficult to obtain a printed coil with good characteristics. In order to solve this problem, the embodiment shown in FIG. 4 is constructed so that a good conductor 5 such as copper or silver is coated on the surface of the flat coil 3 by plating or vapor deposition. The above-mentioned good conductor is not applied to the island pattern 2 in order to maintain low magnetic resistance. In the printed coil having this structure, the flat coil 3 is thicker than the island pattern 2 by an amount equivalent to the amount of the good conductor 5 deposited thereon, and this difference in thickness may cause problems in applications such as multilayer coils. Therefore, in the embodiment shown in FIG. 5, only the flat coil is further etched excluding the iron core island pattern 2 during photoetching to form a thin flat coil 3C, and the above-mentioned good conductor 5 is coated on the surface of the thin flat coil 3C to form the island pattern. This structure has the same thickness as No. 2. The printed coils shown in FIGS. 4 and 5, which are constructed by coating a flat coil with a good conductor, can achieve both low impedance in the coil portion and low magnetic resistance in the iron core island pattern 2, and have good characteristics. We can provide printed coils.

Now, to further explain the method of manufacturing the printed coils shown in FIGS. 4 and 5, in the case of the embodiment shown in FIG. A photoresist is applied uniformly over the entire surface of the iron foil, and then this photoresist is exposed and developed using a mask having the required pattern to form an island pattern and a spiral flat coil. After that, an etching process is applied to form a pattern, and the remaining photoresist is peeled off, thereby forming an island pattern 2 of the same thickness and a spiral flat coil 3 on the sheet member 1. Therefore, when electroplating is performed, the island pattern 2 and the spiral flat coil 3 are not electrically connected, so a good conductor 5 can be plated on the surface of the flat coil 3. The printed coil shown in the figure can be obtained. Note that during this electroplating process, a suitable protective film may be provided on the surface of the island pattern 2.

Similarly, in order to manufacture the printed coil shown in FIG. If a suitable protective film or resist is applied to the surface and a light etching process is applied to reduce the thickness,
Since a thin flat coil 3C can be formed, the thin flat coil 3C can be electroplated and coated with a good conductor 5 to have the same thickness as the island pattern 2 in the same manner as described above, and finally, from the surface of the island pattern 2. By removing the protective film or resist, the printed coil shown in FIG. 5 can be obtained.

"Effects of the Invention" As described above, the printed coil of the present invention has an island-like pattern formed in the center of the coil, which functions as an iron core, independently of the flat coil.
These coil parts and island-like patterns are made of ferromagnetic material such as iron foil, and the flat coil part has a structure that allows a good conductor to be applied, so it is possible to print multilayer coils, large coils, fine pattern coils, etc. There is an advantage in that a product having excellent impedance characteristics in the coil portion and magnetic resistance characteristics in the core portion can be provided as a coil at a low cost using a flexible circuit board method or the like.

According to the present invention, since the flat coil and the island pattern formed independently from the flat coil are made of the same ferromagnetic material such as iron foil, these patterns can be formed in a single etching process. Therefore, there is an advantage in terms of the manufacturing method that it is possible to reduce the number of steps and overall cost while ensuring the relative positional accuracy of these patterns.

[Brief explanation of the drawing]

FIG. 1 is a conceptual plan configuration diagram of a printed coil according to an embodiment of the present invention, FIG. 2 is a cross-sectional explanatory diagram of the printed coil of FIG. 1, and FIG. 3 is a lamination of printed coils of the present invention. FIG. 4 is a conceptual cross-sectional diagram of the multilayer printed coil obtained by the above process, and FIG.
FIG. 2 is a similar cross-sectional view of a printed coil having a structure in which the printed coil shown in the figure is further improved so that the thickness of the flat coil with a good conductor and the thickness of the iron core island pattern are made equal. 1: Insulating sheet member, 2: Iron core island pattern, 3: Flat coil, 4: Connection portion, 5: Adhering good conductor.

Claims (1)

[Scope of Claims] 1. In a printed coil in which a spiral flat coil is formed on an insulating sheet member, the flat coil is formed of a conductor made of a ferromagnetic material, and a central portion of the flat coil is formed of a ferromagnetic conductor. 1. A printed coil characterized in that an island-like pattern of ferromagnetic material is provided that is electrically insulated from the coil and acts as an iron core, and a conductive member is adhered on the surface of the flat coil. 2 Layering printed coils with the above structure in multiple layers,
The printed coil according to claim 1, characterized in that the flat coils between each layer are connected in series and the island patterns are magnetically connected to each other. 3. The printed coil according to claim 1 or 2, wherein the thickness of the flat coil to which the conductive member is attached is equal to the thickness of the island pattern.