FIELD OF THE INVENTION

The invention relates to an electronic device with a cover. The electronic device may for example be an Organic Light Emitting Diode (OLED).

BACKGROUND OF THE INVENTION

The WO 2010/05301 Al discloses an opto-electric device, particularly an OLED, in which internal electronic components are arranged behind a cover plate. The cover comprises embedded conductors that provide electrical access to the interior components.

SUMMARY OF THE INVENTION

Based on this background it was an object of the present invention to provide an improved design for electronic devices with a cover. In particular, it is desirable that the electronic devices shall be cost-effective and/or spatially compact.

This object is achieved by an electronic device according to claim 1 and an electronic system according to claim 12. Preferred embodiments are disclosed in the dependent claims.

The electronic device according to the present invention is characterized by a cover, i.e. a component that mechanically closes the device and borders it to the outside, said cover having at least one feedthrough for providing electrical access to interior components of the electronic device and further providing additional mechanical functionality. As usual, a "feedthrough" shall denote in this context an electrically conductive component that forms a bridge through an object (here the cover) from one side to the other.

By using a feedthrough in the cover not only for its original electrical purpose but also for additional mechanical functions, the described electronic device can realize a highly functional, intelligent design that allows to save both space and cost. There is a plurality of ways how the feedthrough can be designed to provide additional mechanical functionality. According to one important class of embodiments, the feedthrough has a spatial shape or configuration which provides the mechanical functionality. The feedthrough may for example comprise a threaded hole that can receive a screw.

In another class of embodiments of the invention, the feedthrough comprises a magnetic or magnetizable material. These embodiments can particularly be used to attach the electronic device to some carrier by magnetic forces. If the feedthrough comprises a permanently magnetic material, the polarity of this material can cooperate with magnetic fastening spots on the carrier to ensure that attachment is only possible if the electronic device is correctly placed with respect to the carrier, thus preventing a confusion of electrical contacts.

An important mechanical function that can be provided by the feedthrough relates to the mounting of the electronic device in the (hardware-) environment it shall be used in. In a preferred embodiment, the feedthrough therefore comprises an anchor element for mounting the electronic device to a corresponding (compatible) carrier. A simple example of such an anchor element is the threaded hole and the magnetic material mentioned above.

In another realization of the aforementioned embodiment, the anchor element extends above the outer surface of the cover. The anchor element can then interact outside the plane of the cover with some compatible structure in a corresponding carrier. The anchor element can particularly have a three-dimensional form which can interact in a form- fitting manner with a corresponding reception in a carrier.

According to another embodiment of the invention, the feedthrough comprises a through-hole, i.e. an open channel running at least partially through the cover. Such a through-hole can for instance provide a (fluidic) connection between an interior cavity of the electronic device and the outside. This connection may be helpful during the production of the electronic device as it allows an equilibration of pressure between the internal cavity and the atmosphere before the cavity is closed by

encapsulation. In this case the through-hole is at least partially closed at the end of the manufacturing procedure.

In many important applications, there will be two or more feedthroughs in the cover that provide separate electrical access to different interior components of the electronic device, e.g. to leads that have to be supplied with different electrical potentials. According to the invention, at least one of these feedthroughs is designed to provide additional mechanical functionality.

In the aforementioned case, feedthroughs that are associated to different components are preferably arranged in different patterns in the plane of the cover. This implies that it is impossible to bring all feedthroughs which are arranged in a first pattern (and are associated to a first internal component) into contact with terminals that are arranged according to a second pattern (which correspond to feedthroughs associated to a second internal component). The different spatial arrangement of the feedthroughs therefore helps to prevent an electrically wrong connection of the electronic device to some carrier.

In another approach to reduce the risk of connecting the electronic device wrong, at least one feedthrough of plurality of a feedthroughs is provided with a mark, for example a plus ("+") or minus ("-") sign. This mark may optionally be realized by the shape of the feedthrough material itself.

The electronic device may in general serve any purpose, and its electronic components may accordingly be very different in different embodiments. In a practically important case, the electronic device comprises optoelectronic components, particularly Organic Light Emitting Diode (OLED) components. In the latter case, the whole electronic device may just be an OLED. For an OLED, the advantages provided by the invention are particularly relevant: First, OLEDs usually need a cover anyway for sheltering and encapsulating sensitive organic layers. Secondly, it is desirable that electrical contacts and mechanical fixtures consume as a little space as possible because their space is lost for light emission.

The three-dimensional shape or configuration of the cover can in general be quite arbitrary, for example dome-shaped. In a preferred embodiment, the cover comprises a plate of an electrically isolating material in which the feedthrough is embedded.

The invention further relates to an electronic system comprising:

An electronic device of the kind described above, i.e. a device with a cover having at least one feedthrough for providing electrical access to interior components of the electronic device and further providing additional mechanical functionality.

A carrier to which the electronic device can be mounted. A terminal that electrically contacts the feedthrough of the electronic device when this is mounted to the carrier.

The carrier may particularly comprise a structure or component that cooperates with an anchor element and/or a magnetic feedthrough of the kind described above.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. These

embodiments will be described by way of example with the help of the accompanying drawings in which:

Fig. 1 schematically shows a cross section (along line I-I of Figure 2) through an OLED according to the present invention;

Fig. 2 shows a bottom view of the cover of the OLED of Figure 1;

Fig. 3 shows electrical feedthroughs with marks to identify the polarity of the contact;

Fig. 4 shows an electrical feedthrough with integrated mechanical

fixation for OLED mounting;

Fig. 5 illustrates a feedthrough with a through-hole that allows gas

in a cavity to escape.

Like reference numbers in the Figures refer to identical or similar components.

DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will in the following be described with respect to an Organic Light Emitting Diode (OLED), though its principles can be applied in many other situations as well.

Figure 1 schematically shows in a sectional side view the layered design of an OLED 100 according to the present invention. The OLED 100 comprises, from bottom to top, the following sequence of layers and components:

A substrate or carrier 101, typically consisting of a transparent material like glass or plastics. A transparent electrode layer 102, typically made from materials like ZnO, ITO, or PEDOT:PSS.

An organic layer 103 comprising the electroluminescent organic material. Suitable materials for this (multi-)layer are known to a person skilled in the art.

- A second electrode layer 104. If no light emission through the top side of the OLED 100 is required, the second electrode layer may be opaque and for example be made from a metal like copper or gold. In most applications, the second conductor layer 104 is used as a cathode, while the first layer 102 is used as an anode.

Optionally an electrically isolating layer 105 that is disposed above the second electrode layer 104.

A planar cover 110 or cover lid that will be described in more detail below.

Conventional designs of OLEDs differ from that of Figure 1 in that electrical contact pads to different electrode layers are provided on the substrate 101. This conventional approach has two main disadvantages:

1. As the contacts are on the substrate and need to be outside the encapsulated area, the substrate must be larger in size than the encapsulation. This increases the non-light emitting area of the OLED.

2. The limiting factor for the homogeneity of an OLED device is the limited conductivity of the transparent anode. In order to improve the homogeneity, a current distribution structure is desired which surrounds the whole anode. This is not possible if anode and cathode contacts need to be realized on the substrate.

The OLED 100 of the present invention overcomes these disadvantages with a design in which the external electrical contact terminals are inside the area of the substrate 101, such that there is no need any more for contact pads on the substrate.

Instead, electrical access to be interior components of the OLED 100 is provided by feedthroughs 114a, 114b that are embedded in the electrically isolating material 11 1 of the cover 110. The second electrode layer 104 can either be directly contacted by the feedthrough 114b or, as shown in Figure 1, indirectly through an additional via 106 embedded in an isolating layer 105. The first electrode layer 102 is connected to its associated feedthrough 114a in the cover by a via 107 that runs through the organic layer 103, the layer of the second electrode 104 (being electrically isolated from this electrode), and through the isolating layer 105. Figure 2 shows a view onto the bottom side of the cover 110 of the OLED 100. The dashed line I-I indicates the section that is depicted in Figure 1. Two comb-like, interlaced structures 112, 113 of an electrically conductive material are printed onto the bottom side of the cover material 111. These structures distribute the electrical access of the feedthroughs 114a, 114b over the available area. If the cover material 111 is nonconductive (e.g. glass), the feedthroughs 114a, 114b can be realized with glass-metal transitions.

The above basic design and layout of the OLED 100 can be tuned to serve various purposes:

If for example the numbers of anode and cathode contacts are different and/or if they are distributed in different patterns in the plane of the cover 110, the device is fail save against wrong assembly in a housing and therefore against damage due to wrong polarity driving caused by that.

Additionally or alternatively, the external electrical contacts can be marked in such a way that the polarity of the contacts is marked fail save. This is illustrated in Figure 3 for a view onto two terminals of feedthroughs 114c, 114d.

Figure 4 illustrates a design alternative in which the feedthrough 114a comprises an anchor element 116 that extends above the outer surface of the

cover lid 110. In this way a mechanical fixation can be integrated. Easy click fit connections to a carrier C or mechanical connectors can thus be realized easily.

Moreover, the feedthroughs can be made of magnetic (or magnetizable) material. The mechanical mounting to a carrier can then be realized with contact pads on the carrier that are made of ferromagnetic material or of magnetic material with opposite polarity. In this case the mounting is also proof against wrong polarity.

Figure 5 illustrates another design option in which a feedthrough 114b is provided with a through-hole 117 that is favorable in the manufacturing process. During the encapsulation process, a closed cavity is formed by the cover lid 110 and the residual parts of the OLED (substrate etc.). If the air in this cavity is compressed due to the encapsulation process, an overpressure is created. This can be avoided if one or more of the feedthroughs is hollow, thus allowing the gas to escape from the cavity. After the encapsulation process is finished, the through-hole 117 can be closed hermetically. This may for instance be done by applying a droplet of glass frit 118 and then annealing this using a laser beam L to achieve hermetic sealing. Finally it is pointed out that in the present application the term "comprising" does not exclude other elements or steps, that "a" or "an" does not exclude a plurality, and that a single processor or other unit may fulfill the functions of several means. The invention resides in each and every novel characteristic feature and each and every combination of characteristic features. Moreover, reference signs in the claims shall not be construed as limiting their scope.