DE102011015287A1 - Printable multilayer solenoid coil i.e. plunger coil, for use as e.g. sensor for positioning ferromagnetic device for textile processing, has windings separated from each other by isolator, where coil is produced in printing steps - Google Patents

Abstract

The coil has windings (2) printed with conductive ink, laminated on top of each other and comprising an input contact (4) connected to an output contact (5). The windings are separated from each other by an isolator (3). The isolator allows the output contact to remain free. The coil is produced in successive digital printing steps. A ferromagnetic core is formed from electrical insulating layers, which are used for electrical separation of the windings. The coil is printed on a substrate, so that a sensor field is developed. An independent claim is also included for a method for producing a coil.

Description

1. State of the art

Known is the so-called "printable electronics", which instead of visually appealing as possible images or texts, electronic devices are printed in the manner of a conductor matrix or a transistor. Are known single-layer, preferably designed as a conductor spiral coils in the manner of a radio tag antenna, wherein z. B. in a first step, a spiral is applied, in a second printing an insulating pattern, so that in a third printing pass, the turns of the coil excess conductor can be applied. Such a spool is easily printable in a web-fed printing process, in the three-step version described here, both with gravure-type contact printing techniques and with ink-jet digital printing techniques.

Are known with magnetic or magnetizable particles offset liquid polymers z. B. with contact printing method on the type of screen printing can be applied, but can not be processed due to their viscosity with classic inkjet printing.

From textile processing are known variants of inkjet printing, the z. As electromagnetically controlled, miniaturized spray nozzles, and consequently can handle high viscosity inks.

Plunger coils are known, which preferably have the shape of a thick-walled cylinder, and in the z. B. dip a ferromagnet and can induce a voltage. Such coils are known in the art z. B. wound on a bobbin, and are executed in the simplest case as a solenoid, d. H. that they are single-layered in the radial direction and multi-layered in the axial direction. They are in a practically useful form -. B. with a few hundred turns, so as heterogeneous, three-dimensional body - no longer easily printable in a web printing process, certainly not in a contact printing process with a small number of predefined printing forms.

On the other hand, it would be of interest to be able to print coils in one operation together with other electronic components, preferably with magnetic elements, so as to be able to realize printable electromagnetic devices,

2. Description of the invention.

The invention described below achieves the above-mentioned object with a method according to claim 3 and a device according to claim I. Further features of the invention are laid down in the dependent claims.

2.1 Definitions

"Printing" in this document means the application of two-dimensional surface patterns, the term includes z. As "analog" printing method on the type of screen or gravure printing, in which each printing station operates with a rigid printing form, and "digital" printing process in which an ink is applied according to a digital file, and thus is arbitrarily changeable between two printing steps , "Ink" in this document means any fluid that can be applied by a printing process, eg. As classic inks or paints, pastes or powders.

2.2 Description of a preferred embodiment

Preferred is a simple solenoid ( 1 ) created by one turn ( 2 ) is printed with conductive ink. Each turn ( 2 ) an input contact ( 4 ) into which a current flows and an output contact ( 5 ), from which it flows out. After this application, 2 ) with an insulating layer ( 3 ), whereby ( 4 ) and ( 5 ) remains free. The result is in 1 shown strongly schematically.

Now z. B. applied a second turn, which as well as the first turn has an input and an output contact, but now the input contact of the second turn is applied to the output contact of the first turn. Again, an insulator is then applied, which leaves the output contact of the second winding free.

2 shows schematically and preferably how in this way a solenoid with 4 turns is created, in 2 the first turn input and output contacts ( 41 ) and ( 51 ), the second, third and fourth respectively ( 42 ) and ( 52 ) 43 ) and ( 53 ) 44 ) and ( 54 ). Preferably form here ( 41 ) and ( 54 ) the input and output of the coil ( 1 ). Preference is given to the conductor tracks ( 2 ) a few centimeters long, several millimeters wide and less than a micrometer thick; Likewise, the isolator patterns ( 3 ), which separate successive turns and in 2 only hinted at. Preferably ( 1 ) have in principle any number of turns. Preferred is ( 1 ) cylindrical and it is in two successive layers, the input and output contacts along the circumference of these turns ( 2 ) by an integer fraction of 360 degrees so that ( 1 ) entllang the associated cylinder axis has a periodic geometry are preferred ( 2 ) and ( 3 ) after each printing step with a pulsed irradiation (eg pulsed UV) hardened or pre-hardened.

Preferably, a magnetic particle mixed with polymer particles is used as insulator ( 3 ), wherein the magnetic particles were coated with an insulator prior to introduction into the polymer fluid. Preferred are ( 2 ) and ( 3 ) is substantially circular and it is thereby ( 3 ) no longer as a scored ring, but as a scored, with ( 2 ) concentric disc, so that a solenoid coil with ferromagnetic core is printable in this way.

3. Further embodiments of the invention

Preferably, a coil ( 1 ) is made with many turns by passing a substrate a suitable number of times through two inkjet printing stations, each of which has a conductive winding ( 2 ) and the associated insulator ( 3 ) Instruct. Preferably, the distance between the ink jet printhead and ( 1 ) are kept constant.

Preferably, instead of or in addition to a photochemical curing, a thermal or microwave or HF curing can be used.

Preferred is ( 1 ) can be printed as a plunger coil, and covered with an elastic foil which has a magnet, such that vibrations of the magnet cause a current in ( 1 induce; conversely, a in ( 1 ) fed current to move the magnet. Thus, the plunger coil can act as a sensor or actuator.

Preferably, the magnet is printed on the film. Preferably, the film is formed of a porous elastomer, and the magnet is made of a magnetizable polymeric and printable / material, which can now adhere particularly strongly to the film.

Preferably, the magnetizable polymer is magnetized inhomogeneously after curing, so that the temporal variation of ( 1 ) magnetic field is increased.

Preference is given ( 1 ) after creation on a surface ( 6 ) with a porous elastomer ( 7 ) and the resulting elastic depression is coated with a magnetizable polymer ( 8th ), such that the plug ( 8th ) in the coil, which is preferably used as a plunger coil ( 1 ) can move vertically and laterally. This device can act as a sensor or actuator after a magnetization.

Preferably includes ( 1 ) several radially superimposed layers. When the coil according to the invention is produced on a substrate, a number of conductive surfaces are preferably printed on top of one another in such a way that a column of conductive material is produced. Such a column preferably connects two coils according to the invention with one another, wherein z. B. the output of the first coil is connected to the input of the second coil.

4. Advantages and preferred applications of the invention

The invention contributes to "printable electronics" by adding electromagnetic devices.

Preferably, a coil according to the invention is applied so that it can be used as a primary or secondary coil of a transformer. Such a transformer can, for. B. be used for wireless charging a battery.

Preferred is a number of coils described above ( 1 ) printed on a substrate, so z. B. a sensor array in the manner of a microphone array or actuator array in the manner of an acoustic array for directional sound radiation arises.

Preferably, a number of coils ( 1 ) are printed on a substrate to realize a rotary or a linear motor. The coils are preferably ( 1 ) miniaturized and controllable as a two-dimensional field. Preferably, with such a one- or two-dimensional switchable array, a magnetically doped liquid drop is movable on a surface.

Claims (6)

Multi-layer coil ( 1 ), of at least two superimposed, printable turns ( 2 ), wherein - each turn ( 2 ) an input contact ( 4 ) and an output contact ( 5 ), and wherein, starting from the second turn, with each turn, the input contact of which is connected to the output contact of the underlying turn, and wherein - each two superimposed turns of the coil are separated from each other by a printable interlayer ( 3 ), but which isolate the output contact ( 5 ) leaves the lower turn free, and where - ( 1 ) can be created in a number of successive printing steps. Kitchen sink ( 1 ) according to claim 1, which has a magnetizable printable core, which may preferably be formed of electrically insulating layers, which are also used for the electrical separation of two successive turns according to claim 1. Method for creating a coil ( 1 ) according to one of claims 1 to 2, with digital printing methods for conductive inks and for insulators. Method according to one of claims 3 or 4, wherein the printed windings and insulator layers are hartbar after each printing pass, preferably by irradiation of pulsed light or electromagnetic radiation in the manner of a microwave curing. Method according to one of claims 3 to 5 for the use of a number of coils printed on the same substrate ( 1 ). Method according to claim 5 for using a number of coils ( 1 ) as an electromechanical actuator or sensor, or as part of a transformer, or as a printable electric motor, or as a linear motor for one or two-dimensional positioning of a ferromagnetic device.

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