EP2732483A1

EP2732483A1 - Light module with reduced surface area requirements

Info

Publication number: EP2732483A1
Application number: EP12740925.8A
Authority: EP
Inventors: Michael Eritt; Jörg AMELUNG
Original assignee: Tridonic Dresden GmbH and Co KG
Current assignee: Tridonic GmbH and Co KG
Priority date: 2011-07-12
Filing date: 2012-07-12
Publication date: 2014-05-21
Also published as: DE102011079014A1; CN103718323A; CN103718323B; WO2013007781A1

Abstract

In a light module (1) with a planar active element (11) and a planar carrier element (10), with a surface on which the active element (11) is arranged, the carrier element (10) having a protruding area relative to the active element (11), encapsulation means (21) laterally enclosing the active element (11) are provided in the protruding area. Located outside of the encapsulation means (21) are electrical terminals (30), configured as conductors, for supplying power to the active element (11), said conductors being arranged perpendicularly to the plane of the active element (11) and extending at least partially on the outer periphery of the encapsulation means (21).

Description

Light module with reduced space requirement

The present invention relates to a lighting module according to the preamble of claim 1, which has a plate-shaped active element for emitting light, which is arranged on a carrier element. The active element may in particular be an OLED (organic light emitting diodes) structure or a QLED (quantum dot light emitting diodes) structure.

The development of novel light sources, which due to their improved

The ability to replace classic light sources such as incandescent or fluorescent lamps has made significant progress lately. In addition to classic light-emitting diodes (LEDs), which are essentially punctiform

In particular, OLEDs or QLEDs are also the focus of attention since novel surface light elements can be realized on the basis of such structures. As a flat luminaire with a moderate luminance compared to a classic LED, an OLED or QLED is ideally suited for the production of flat, diffuse light sources. The

Applications for such light sources are extremely diverse, which is why there has been a strong development in this field in recent years. Owing to its structure, an OLED or QLED has the properties of a so-called Lambertian radiator with a constant luminance at arbitrary emission angles. Accordingly, it is particularly suitable for forming large-area light sources.

An OLED or QLED represents a current-driven component. Accordingly, a homogeneous current distribution over the luminous area is extremely important in order to achieve a uniform and homogeneous light emission. A limitation of this homogeneity is given by the required transparent electrode, which is to be arranged at least on one side of the OLED or QLED structure. This transparent electrode is usually formed on the basis of transparent conductive oxides (TCO) or extremely thin metal layers. Due to the low conductivity of these materials, however, there is a limitation of

Homogeneity. The aforementioned limitations mean that the maximum realizable area of OLED or QLED surface radiators is limited. To the stream to the

Furthermore, circulating current conductors are required. In previous known embodiments, these current conductors are usually made of non-transparent metal films with a high through further interconnects

Conductivity formed. These form a broad, non-luminous frame around the luminous surface, as can be seen in FIG.

FIG. 4 shows the basic structure of a planar OLED or QLED surface illumination element 100, as is known from the prior art, in a plan view. The reference numeral 110 designates a carrier substrate, which is usually formed of glass, a transparent plastic film or a similar material. On this carrier substrate 110, the active OLED or QLED structure 111 is arranged, which is supplied via the anode terminals 112 and the cathode terminals 113 with power. The connection of these terminals 112 and 113 to the active surface 111 via conductor tracks 112a and 113a, which as a

Edge encapsulation 121 bridge formed and the active surface 111 surrounding area. The encapsulation 121, which may typically be of a glass, a plastic film or the like, serves to protect the active structure 111 from external influences. In particular, the penetration of moisture and oxygen into the structure 111 is thereby avoided. The interconnects 112a and 113a bridging the encapsulation 121 are usually formed from ITO or alternatively from FTO, ZnO, PEDOT or the like. As can be seen from the illustration of FIG. 4, the carrier element 110 has a projection on the outer circumference of the active surface 111, which projection is used to arrange the connections 112 and 113 formed as planar conductor tracks. In this case, a certain width of the supernatant is required in order to be able to ensure a sufficient conductivity for the connections 112, 113, which is ultimately necessary in order to be able to supply the active layer 111 with sufficient current. However, this in turn has the consequence that the active layer 111, that is to say the actual luminous area of the arrangement 100, is surrounded by a non-luminous frame. If several such lighting elements 110 are to be combined with each other to a larger areal arrangement, this is the

Overall impression of the received luminous area impaired.

The present invention is therefore based on the object of specifying a novel solution for realizing a lighting module, in particular based on an OLED or QLED, in which the disadvantages just described are avoided. The object is achieved by a lighting module, which has the features of claim 1. Advantageous developments of the invention are the subject of the dependent claims.

The core idea of the solution according to the invention is to arrange the electrical connections for the power supply of the active element of the lighting module in a novel manner. As before, these connections are formed by conductor tracks which, however, according to the invention are now arranged perpendicular to the plane of the active element and run at least partially on the outer circumference of encapsulation means which laterally surround the active element.

According to the present invention, a lighting module is accordingly proposed, which has:

a plate-shaped, active element,

a plate-shaped carrier element having a surface on which the active element is arranged, wherein the carrier element has a region projecting with respect to the active element,

- located in the region of the supernatant, the active element laterally

enclosing encapsulants,

- located outside of the encapsulant electrical connections, which are designed as interconnects,

- Located between the support member and the encapsulation means and connecting the terminals to the active element electrical

Links,

wherein according to the invention, the conductor paths forming the electrical connections are arranged perpendicular to the plane of the active element and run at least partially on the outer circumference of the encapsulation means.

As will be explained in detail later on the basis of several exemplary embodiments of the present invention, a significant reduction of the required edge area for the lighting module can be obtained by the configuration according to the invention, in particular by the novel arrangement of the electrical connections. An at least slight projection of the substrate, on which the OLED or QLED structure is arranged, is furthermore required in order to allow circumferential encapsulation, that is, sufficient protection of the active layer. The erfmdungsgemäße solution, however, allows a significant reduction of this supernatant compared to previously known solutions, so that ultimately the non-luminous frame can be minimized. This advantage already comes with However, to carry individual light elements, but in particular also affects arrangements with several lighting modules according to the invention, since now the proportion of non-luminous surface drastically reduced and thus the homogeneous light emission over the entire surface of the arrangement can be improved.

Preferably, a plate-shaped encapsulation substrate is arranged on the side of the active element opposite the carrier element, which also protects the side of the active element opposite the substrate. The electrical connections which are formed by the conductor tracks are in this case preferably arranged on the outer circumference of the encapsulation substrate. In particular, the terminals may extend over the entire height of the encapsulant substrate, even with the possibility that the interconnects extend over both the height of the encapsulant substrate and the height of the carrier member. A sufficient width of the conductors forming the electrical connections is thus ensured in each case, which is of high relevance in view of the required power supply to the active element.

The lateral encapsulants may be formed, for example, by a peripheral frame of the encapsulant substrate. Alternatively, it would also be conceivable to form the encapsulation means by an adhesive material that is effective between the carrier element and the encapsulation substrate. The

Encapsulation substrate itself can be made opaque or alternatively also made of a transparent material, for example of glass or plastic. In the case of a translucent execution is accordingly a

Light emission on both sides of the active element possible. Also, the support element, which usually forms the primary emission surface of the arrangement, is

preferably formed from a translucent material, in particular glass or plastic.

As already mentioned, the active element is preferably formed by an OLED or QLED structure.

A preferred example of application of the solution according to the invention consists of a planar lighting arrangement, which consists of a plurality of lighting modules, which are connected in series or in parallel with each other. The electrical connection of the lighting modules with each other can be done in particular via the laterally arranged electrical connections. Also this advantage of the simple Connection of the light module with each other results from the inventive lateral arrangement of the connections.

The invention will be explained in more detail with reference to the accompanying drawings. Show it:

Figures la and lb views of a first embodiment of a lighting module according to the invention; Figures 2a and 2b are views of a second embodiment of a lighting module according to the invention;

Figures 3a and 3b are views of a third embodiment of a lighting module according to the invention and

FIG. 4 shows a lighting module according to the known state of the art

Technology.

As already mentioned, due to the limited conductivity of at least one electrode of an OLED or QLED structure, voltage drops and thus inhomogeneous luminance distributions occur. In order to suppress such effects as effectively as possible, it is necessary to direct the current homogeneously from the edge into the luminous area. For better power distribution around the active element around reinforced tracks are arranged, which allow the power supply. Due to the required conductivity of these connections, however, metallic and therefore non-transparent conductor tracks are used, which lead to a non-luminous frame around the light-emitting surface. Furthermore, the active structure should be protected from environmental influences, which is why an encapsulation is provided by default. This is the current state of the art by a

Edge encapsulation is realized, which is why an area is to be provided around the active surface in order to allow a bonding of encapsulation substrate and carrier substrate. Such measures limit the possibilities for interconnecting a plurality of light-emitting elements to form larger, homogeneous illuminated areas, since basically non-emitting areas remain between the individual luminous areas, giving the overall impression of the luminous area

deteriorate.

Due to the inventive displacement of the leads to the vertical edge of the encapsulant, it is now possible, however, the cross section of this non-emitting area around the OLED or QLED structure. At the same time a simple, direct interconnection of several individual light-emitting elements to a larger light-emitting surface is made possible by this measure. This idea according to the invention will be explained in more detail below with reference to the exemplary embodiments of FIGS. 1 to 3.

The figures la and lb show - in plan view and in sectional view - first a first embodiment of a lighting module 1 according to the invention, which is still very similar to the known from the prior art and shown in Figure 4 module 100. So again is on a flat support element or

Carrier substrate 10, which is preferably formed of glass or a translucent plastic film, an active, plate-shaped element 11 arranged in the form of an OLED or QLED. The side of the active surface 11 opposite the carrier substrate 10 is covered by an encapsulation substrate 12 which, depending on whether light emission on both sides or only in one direction is desired, is again made of a light-transmissive material (for example glass or plastic) or an opaque material can be formed.

Main task of this encapsulation substrate 20 is primarily to protect the back of the active layer 11 from external influences, in particular to prevent the ingress of moisture, oxygen or the like.

For an all-round protection, however, a lateral sheathing of the active surface 11 is required. This is formed in the present case by a peripheral frame 21. The frame 21 is preferably integrally connected to the encapsulation substrate 20, so part of the

Encapsulation substrate 20, but could alternatively be formed by a separate component. The encapsulation substrate 20 with the frame 21 thus forms an approximately square recess, in which the active element 11 is inserted. Through the carrier substrate 10 and the encapsulation substrate 20 with the

Frame 21 is accordingly the active element 11 completely or sheathed on all sides.

To power the active element 11 are again cathode and

Anode connections required, which must have sufficient conductivity and are therefore designed as a flat conductor tracks. in the

In the exemplary embodiment illustrated in the sectional view of FIG. 1b, the lateral anode connections 30 can be seen, which are connected to one another at two

opposite longitudinal sides of the light module 1 are arranged. The two cathode connections are arranged on the two further longitudinal sides of the module 1 and accordingly not visible in FIG. A connection between the terminals 30 and the active element 11 via feeds 13 a, which are arranged between the carrier substrate 10 and the peripheral frame 21 and may consist of ITO, FTO, ZnO, PDOT or similar materials. The connection between the terminals 30 and the leads 13a via conductive adhesive and / or by bonding or soldering.

The peculiarity of the solution according to the invention consists in the fact that the terminals 30 are in turn designed as planar printed conductors, but now not aligned parallel to the plane of the active element 11 but perpendicular thereto and arranged on the outer circumference of the encapsulation substrate 20 and the frame 21. Accordingly, despite substantially the same area of these terminals 30 compared to the solution of Figure 4, no further protruding portion of the support substrate 10 is required, so that the thickness of the rotating frame, which does not light, substantially to the dimensions of

Edge caps 21 is limited. Since such a frame typically has a width of about 1 to 2 mm from the outer edge of the carrier substrate 10, as compared to the solution in Figure 4, a significant reduction in the area requirements, in particular the non-luminous area can be achieved.

It should be noted that in the illustrated figures, the thickness of the active element 11 to illustrate the inventive concept is shown clearly exaggerated. In reality, this OLED or QLED structure 11 has an extremely small thickness compared to the carrier substrate 10 and / or encapsulation substrate 20. Furthermore, applies both for the embodiment of Figures la and lb as well as for the other exemplary embodiments according to the invention that the invention is not limited to square lighting modules. Instead, the light module may have any shape, in particular a polygonal shape or a rotationally symmetrical or oval shape. However, in particular structures are preferred, which allow a planar merging of several such lighting modules to a gapless larger luminous area.

A further improvement or reduction of the circulating, non-luminous edge can be achieved according to the variant illustrated in FIGS. 2a and 2b, wherein identical elements are again provided with the same reference numerals. In this second embodiment, the Randverkapselung is replaced by means of the circumferential frame 21 in the first embodiment by a so-called Vollflächenverkapselung. In this case, no circumferential frame 21 is now provided, which protects the lateral extent of the active element 11. Instead, the

Encapsulation on the outer circumference of the active element 11 by an adhesive material, which is initially used to the three planar structures, ie

Carrier substrate 10, active element 11 and encapsulation substrate 20 to connect together. When joining these three elements 10, 11 and 20 of the adhesive is pressed into the peripheral region and this includes the side of the active element 11 a. In this variant, the encapsulation substrate 20 requires only a very slight lateral projection with respect to the active element 11 in order to allow full encapsulation of the active element 11. In the area of the laterally enclosing adhesive, in turn, the feeders 13a are provided, which enable the electrical connection between active element 11 and terminals 30. The terminals 30, so the traces for powering the

Anode and the cathode are in turn arranged on the outer circumference of the encapsulation substrate 20, wherein now, however, the peripheral frame 21 is no longer present. A comparison of the figures la and lb with the figures 2a and 2b shows directly that in this second embodiment, the non-luminous edge region can be further reduced. In particular, the remaining width of this edge region can be reduced to a value of about 1 mm or even less.

Finally, in the third variant of FIGS. 3 a and 3 b, in which analogous to FIGS. 2 a and 2 b a full area encapsulation is again provided, the outer periphery of the luminous module 1 is almost completely formed by the connections 30 or the connections located on the other two side surfaces. The interconnects 30 now extend over the entire height of the luminous module 1, that is to say both over the height of the encapsulation substrate 20 and the carrier substrate 10. Due to the increased area of the interconnects 30, an even better Slxom feed can be achieved. In addition, in comparison to the previously discussed embodiments, the conductor thickness can be reduced.

The interconnects 30 project slightly into the gap between the carrier substrate 10 and the encapsulation substrate 20 in the edge area of the active element 11. In order to facilitate the contact between the contact areas 30 and the feeds 13a, it is preferable for the encapsulation substrate 20 to be in the

Edge region slightly bevelled, that is sloping outwards. The resulting area requirement for the non-luminous frame corresponds to Essentially the space requirement of the second exemplary embodiment. Alternatively, in this case, the production of the side contact surfaces can also take place by means of printing or dispensing processes, which makes possible a simple and cost-effective variant of the production of OLED or QLED surface radiators.

The lateral, vertical arrangement of the connections also leads, as already mentioned, to the fact that a connection of a plurality of corresponding lighting modules to a flat luminous element is facilitated. The direct interconnection of several

Individual elements can be facilitated in particular by the attachment of corresponding contact pads on the edge of the structure. The modules can be connected to each other both serially and in parallel, with the particular advantage that the proportion of non-luminous surfaces and spaces can be significantly reduced. Accordingly, a uniform and homogeneous light emission can be achieved over a large area.

Claims

claims

1. light module (1), comprising

A plate-shaped, active element (11),

A plate-shaped carrier element (10), with a surface on which the

active element (11) is arranged, wherein the carrier element (10) with respect to the active element (11) has a projecting portion,

• located in the region of the supernatant, the active element (11) laterally

enclosing encapsulants (21),

• outside of the encapsulation means (21) located electrical connections (30) for the power supply of the active element (11), which are designed as conductor tracks, as well as

Between the carrier element (10) and the encapsulation means (21)

located and the terminals (30) with the active element (11) connecting electrical connections (12a, 13a),

characterized,

in that the interconnects forming the electrical connections (30) are arranged perpendicular to the plane of the active element (11) and run at least partially on the outer circumference of the encapsulation means (21).

2. Light module according to claim 1,

characterized,

in that a plate-shaped encapsulation substrate (20) is arranged on the side of the active element (11) opposite the carrier element (10).

3. Light module according to claim 2,

characterized,

in that the interconnects forming the electrical connections (30) are arranged on the outer circumference of the encapsulation substrate (20).

4. Light module according to claim 3,

characterized,

in that the interconnects forming the electrical connections (30) extend over the entire height of the encapsulation substrate (20).

5. Light module according to claim 4,

characterized,

in that the interconnects forming the electrical connections (30) extend over both the height of the encapsulation substrate (20) and the height of the carrier element (10).

6. Light module according to one of claims 2 to 5,

characterized,

in that the lateral encapsulation means (21) are formed by a peripheral frame of the encapsulation substrate (20).

7. Light module according to one of claims 2 to 5,

characterized,

in that the lateral encapsulation means are formed by an adhesive material which acts between the carrier element (10) and the encapsulation substrate (20).

8. Light module according to one of claims 2 to 7,

characterized,

in that the encapsulation substrate (20) is formed of a transparent material, in particular of glass or plastic.

9. Light module according to one of the preceding claims,

characterized,

the active element (11) is formed by an OLED or QLED structure.

10. Light module according to one of the preceding claims,

characterized,

the carrier element (10) is formed from a transparent material, in particular from glass or plastic.

11. Flat lighting arrangement consisting of a plurality of lighting modules (1) according to one of the preceding claims, wherein the lighting modules (1) via the electrical connections in series or in parallel are interconnected.