This application is the U.S. national phase of International Application No. PCT/FI2018/050618 filed 31 Aug. 2018, which designated the U.S. and claims priority to FI Patent Application No. 20175786 filed 1 Sep. 2017, the entire contents of each of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates to flexible electronics technologies and more particularly to flexible electronic foils comprising a flexible substrate and at least one electrically conductive portion arranged to the substrate.

BACKGROUND OF THE INVENTION

Flexible electronics technologies enable manufacturing of thin, flexible and cost-efficient electronics devices or products. Presently used solutions for joining electronic foils to these devices or to each other are based for example on rigid connectors that are either crimped or glued to the foil. Alternatively also conductive tapes or glues are used for joining the foils to these devices or to each other.

Using of the rigid connectors for joining the electronic foils ruins many of the benefits provided by the flexible electronic technologies. These connectors makes the intended structure much thicker but still not guarantee mechanical durability of the structure. The connectors also increase the costs remarkably. These connecters itself must also be connected to the foils what also adds extra components in the structure and the costs thereof.

The connectors cannot typically also be made wide enough to direct uniform stretching force to the foil. Most of the presently available commercial connectors are designed to be used with traditional rigid printed circuit boards or flexible solderable printed circuit boards. The connectors also require applying additional processes and manufacturing phases to the production line that are not practical and compatible with the streamlined flexible electronics manufacturing flow.

The conductive tapes or glues between the foils or between the foil and the device can provide instantaneously electrical connectivity. However, they have a limited mechanical strength, especially under static loading. The electrical properties of the conductive tapes and glues also change during aging. The tapes and glues are also unpractical, especially in field use applications. For example the glues can easily spill outside the intended application area and the tapes are difficult to align properly. The tapes and glues provide also a permanent connection that cannot be easily unmounted if at all without breaking the structure and at least drastically weakening the performance.

Same kind of limitations are also relevant for lamination based joining technologies, which additionally require specific lamination machines with heating and pressure devices.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to provide a novel solution for joining of electronic foils.

The invention is characterized by the features of the independent claims.

The flexible electronic foil comprises a flexible substrate and at least one electrically conductive portion arranged to the substrate. The electronic foil further comprises mechanical fastening means that are part of the substrate for mechanical fastening of the electronic foil. The mechanical fastening means are intended to be used for joining or fastening or attaching the electronic foil mechanically for example to an object intended to provide a counterpart for the electronic foil.

The joining solution provided by disclosed electronic foil is cost efficient to manufacture because there is no need for any additional parts to provide the joint of the electronic foil to an object providing a counterpart for the electronic foil. The joining solution described not necessarily only join or fasten the two objects mechanically together but at the same time it may also be used to align the objects to be joint together and possible electrically conductive portions therein relative to each other.

Some embodiments of the invention are disclosed in the dependent claims.

