WO2013007744A1

WO2013007744A1 - Light module with controllable light guidance

Info

Publication number: WO2013007744A1
Application number: PCT/EP2012/063559
Authority: WO
Inventors: Michael Eritt; Christian Kirchhof
Original assignee: Ledon Oled Lighting Gmbh & Co. Kg
Priority date: 2011-07-12
Filing date: 2012-07-11
Publication date: 2013-01-17
Also published as: DE102011079012A1; CN103718322A; EP2732482A1; CN103718322B

Abstract

The invention relates to a light module having a plate-shaped active element (12), and a plate-shaped carrier element (10) comprising a surface (101) on which the active element (12) is arranged. The light module also comprises a transparent light-emitting element (10') that is preferably formed by the carrier element (10). At least part of a surface (102) of the light-emitting element (10') is also furnished with an active or variable optical structure (200). Said structure can comprise, for example, two electrodes and a material therebetween, the shape of the structure (200) changing based on a voltage applied to the electrodes. The optical structure (200) enables the directional distribution of the light generated by the active element (12) to be influenced in a targeted manner. In other words, the emission characteristic can be controlled in a targeted manner. The light module is thus particularly suitable for realizing oriented lighting, e.g. for illuminating objects.

Description

Light module with controllable light control

The invention relates to a lighting module with a plate-shaped, active element and a plate-shaped support member having a surface on which the active element is arranged, and with a transparent light-emitting element, which is preferably formed by the support member.

Such a light-emitting module is known from the prior art in the form of an OLED lighting module (OLED: organic light-emitting diode). The OLED light module comprises a plate-shaped, active element in the form of two electrodes and an organic layer arranged between the electrodes, which emits light when current is applied to the electrodes. The active element is arranged on a plate-shaped support element in the form of a glass plate or film made of plastic or metal. Through the glass plate, the light generated by the active element can leave the OLED module, so that the glass plate is a transparent light-emitting element.

Due to its structure, an OLED acts as a Lambert 'em radiator. At the transition from the glass plate to the air in the adjacent outer space, total reflections occur due to the different refractive indices. As a result, the efficiency of the light extraction is limited.

The luminance is thus at least approximately independent of the emission angle. A clear light output in a targeted direction is therefore not possible with the known light module as such. This can be particularly disadvantageous if the light module is to be used as a surface-emitting luminaire or as part of such a luminaire, wherein light is to be emitted predominantly into a specific solid angle range.

The invention is based on the object, a corresponding improved

Specify light module. In particular, the lighting module should be improved

Have light emission properties. This object is achieved according to the invention with the object mentioned in the independent claim. Particular embodiments of the invention are specified in the dependent claims.

According to the invention, a lighting module is provided, which has a plate-shaped, active element, and a plate-shaped support member having a surface, on which the active element is arranged. The light-emitting module also has a transparent light-emitting element, which is preferably formed by the carrier element. In this case, at least a part of a surface of the light-emitting element is provided with an active or variable optical structure.

The optical structure makes it possible to specifically influence the directional distribution in the output of the light generated by the active element. In other words, the emission characteristic of the

Controlled light module targeted. In this way, the light module is particularly well suited for the realization of a directed illumination, for example for the illumination of objects. It is also possible to restrict a radiation angle of the light to be emitted; As a result, for example, in the case of a corresponding luminaire, a glare limitation can be effected.

In addition, the optical structure with respect to the plate-shaped

Make carrier element very flat, so that the height of the light module can be kept low overall.

The optical structure can also cause fewer totaheeflexions to occur on the surface of the light-emitting element, so that the light extraction efficiency of the light-emitting module can be increased in this way.

Preferably, the active or variable optical structure comprises two transparent electrodes and a material located between the electrodes, the structure of which varies as a function of an electrical voltage applied between the electrodes. This makes it particularly easy to achieve a controllable influence on the emission characteristic. Preferably, the material located between the electrodes is a through

Elastomer or acrylates or an acrylate formed. Alternatively, it may be formed by, for example, an amorphous fluoropolymer.

Advantageously, the light module is designed such that the material located between the electrodes has a structure. This structure may advantageously have a lens structure or be formed from such a lens structure. Alternatively, this structure may have or be formed of a prism structure. This is particularly well suited for targeted light control.

Advantageously, the structure may be formed differently in different areas. As a result, a special lighting effect can be achieved. The structure may therefore have, for example, different microstructures in different areas on the surface of the light-emitting element, for example prisms in a first region and lenses in a second region or prisms of a first orientation in a first region and prisms of a second orientation in a second region different from the first orientation.

The active or variable optical structure can advantageously extend over the entire surface of the light module. Alternatively it can be provided that extends the active or variable optical structure only over a portion of the surface of the light module. This also makes special

Light effects with the light module can be achieved. In particular, this allows a combination of directed and undirected light output; this can be used, for example, to generate symbols on the light emission surface of the

Light module can be used.

Preferably, between the transparent light-emitting element and the active or variable optical structure another, with respect to their properties not changeable or not changeable optical structure is arranged. This further optical structure may in particular have or consist of a Lmsen structure. As a result, in particular a further increase in the light extraction efficiency can be achieved. The light-emitting element may be formed by the carrier element and / or be formed by an encapsulation which is arranged on a side of the active element opposite the carrier element. Optionally, differently structured regions of the active or variable optical structure may also be formed on the encapsulation and / or the optical structure may optionally be formed differently on the side of the carrier element than on the side of the encapsulation. Preferably, the active element is formed by an OLED or QLED structure.

The invention is explained in more detail below with reference to exemplary embodiments and with reference to the drawings. It shows: a sketchy sectional view of a first

Exemplary embodiment of a lighting module according to the invention,

Figures 2a and 2b further sketches to the first embodiment to the

Light-emitting surface of the light-emitting element,

Figures 3 a and 3 b corresponding sketches to a second

exemplary embodiment,

Figures 4a and 4b corresponding sketches to a third

Exemplary embodiment, and 5b corresponding sketches to a fourth

exemplary embodiment,

Figures 6a and 6b is a plan view and a sectional view of an embodiment with differently shaped surface areas and

Figures 7a and 7b corresponding sketches for another example with

differently designed surface areas. In Fig. 1 an exemplary embodiment of a lighting module according to the invention is sketched in section. The light module comprises a plate-shaped, active element 12. The active element 12 is designed to generate a light when an electrical current is applied. The active element 12 may comprise two electrodes, as well as an organic layer disposed between the electrodes, wherein upon application of the current to the electrodes, the organic layer generates the light. The active element 12 may comprise or consist of an OLED. The active element 12 may alternatively comprise or consist of a QLED (QLED: quantum dots light emitting diode). If the execution of the active element 12 with an opaque electrode, light is emitted only in the direction of the transparent second electrode of the active element 12; if, on the other hand, both electrodes of the active element 12 are made transparent, the

Light emission down and up.

Furthermore, the lighting module comprises a transparent carrier element 10, which has a surface 101 on which the active element 12 is arranged. The carrier element 10 may be a carrier substrate, in particular in the form of a glass plate or plastic film or plate.

The light module also includes a transparent or translucent

Light-emitting element 10 ', which - as in the example shown the case - can be formed in particular by the support member 10. In addition, the lighting module can have an encapsulation 11, which is arranged opposite the support element 10 with respect to the active element 12 and which is designed to protect the active element 12 from undesired environmental influences. The encapsulation 11 may also be designed plate-shaped. In that regard, the lighting module may correspond in particular to the known light module described above.

The light module can be designed as a lamp or as part of a lamp; For this purpose, the light emitting surface 10 'in particular as a light emitting surface of the lamp or serve as part of the light emitting surface of the luminaire. For example, the

Lichtabgabefläche 10 'have a size of more than 1 cm by 1 cm, preferably more than 3 cm by 3 cm. A charge L of the light generated by the active element 12 is through the

Light emitting element 10 'provided therethrough. For description, it is assumed below that the light module of the sketch in FIG. 1 is oriented in such a way that this output L takes place in the upper half space, that is to say briefly "upwards".

In addition, in the case of a transparent encapsulation 11, a further delivery L 'of the light generated by the active element 12 with respect to the active element 12 may be provided in an opposite direction, or in the lower half space or shortly "downwards".

The light-emitting element 10 'can also be formed by the encapsulation 11. Also, the light emitting element 10 'may be formed on the one hand by the support member 10 and on the other hand by the encapsulation 11, so be carried out in two parts. For the sake of brevity, the case where the light-emitting element 10 'is formed by the support member 10 will be considered below. In one of the further possible cases of the configuration of the light-emitting element 10 ', the description is to be correspondingly adapted to understand.

At least part of a surface 102 of the light emitting element 10 'is provided with an active or variable optical structure 200. Accordingly, the light-emitting module is configured in such a way that the light generated by the active element 12 at least partially passes first through the light-emitting element 10 ', then leaves the optical structure 200 and subsequently the light-emitting module. The surface 102 may be, in particular, a surface of the

Light emitting element 10 ', which is arranged opposite to the active element 12. In the example shown, the "upper" surface of the

Light emitting element 10 ', that surface 102 which is at least partially provided with the optical slab Kr 200. If the optical structure 200 is at least partially arranged on the encapsulation 11, it is preferably provided accordingly-with reference to FIG. 1 -on the downwardly facing surface of the encapsulation 11.

In FIGS. 2a and 2b, an enlarged detail of FIG. 1 is sketched. The surface 102 of the light-emitting element 10 'can be seen with the optical structure 200. The optical structure 200 can be changed as mentioned, and in FIGS. 2a and 2b two states of the optical structure 200 that are different in this sense are sketched by way of example.

The active or variable optical structure 200 preferably comprises a first transparent electrode 21 and a second transparent electrode 22, as well as a transparent material 20 located between the electrodes 21, 22 or a transparent layer located between the electrodes 21, 22; whose structure or shape changes as a function of an applied between the electrodes 21, 22 electrical voltage U. In this way, by changing the voltage U, the directional behavior of the light emitted by the lighting module can be influenced in a targeted manner. The optical structure 200 in this sense represents an "adaptive" element or an "adaptive optic", the material 20 an "active material" or a "deflection layer".

The first electrode 21 can-in particular directly-be arranged flat on the surface 102 of the light-emitting element 10 ', the second electrode 22 above the material 20. The electrodes 21, 22 can consist of an electrically conductive material, for example of ITO (indium-tin oxide), FTO (fluorine-doped tin oxide), ZnO (zinc oxide), PEDOT (polyethylenedioxythiophene) or the like.

The material 20 may be one of materials that changes surface tension based on "electrowetting," such as an amorphous fluoropolymer, and may also be an electroactive material, such as an elastomer or the like an acrylate. Specifically, the optical structure 200 may be formed to change its shape in response to said voltage such that the light generated by the active element 12 undergoes directional control as it passes through the optical structure 200 is dependent on the voltage U. In particular, individual optical elements 25 can be formed by the optical structure 200, which are distributed over at least part of the surface 102 of the light emission element 10 ', wherein these optical elements 25 a

Forming a light-steering syndrome. For example, the structure or shape of the material 20 or of the layer between the electrodes 21, 22 may be formed by impressing. By way of example, the structure may have a lens structure, in particular a microlens structure, or may be formed by a lens, as exemplified in FIGS. 2 a and 2 b. The optical elements 25 are therefore lenses or microlenses in this case. In Fig. 2a, a state is sketched in which no voltage U is applied to the electrodes 21, 22, in Fig. 2b, a further state in which a voltage U is applied.

The configuration can be such that a radius of curvature of the corresponding lenses changes as a function of the voltage U, for example becomes smaller with increasing voltage U. Said change in shape of the optical structure 200 causes a change in the vertical extent of the optical structure 200. This process is reversible and, on removal of the applied voltage U, leads to a regression in the region sketched in FIG. 2a

Initial state in which no voltage U is applied.

Preferably, the optical structure 200 is formed very flat, so that the

Total light module can be executed with a low overall height. For example, it may be provided that the optical structure 200 has a smaller vertical

Extension or extension normal to the surface 102 of the

Light-emitting element 10 '- has as the carrier element 10th

The optical structure 200 may be formed as a film or a thin layer. Starting from the state shown in Fig. 2a, in which no voltage U is applied to the electrodes 21, 22, the microlenses used in this embodiment increase their focal length upon application of the voltage U. This is indicated by arrows in Figs. 2a and 2b the optical elements 25 indicated. In the limiting case of a "maximum" voltage U, the second electrode 22 runs quasi-parallel to the first electrode 21.

By way of the optical structure 200, in principle an increase in the coupling-out efficiency can be achieved by reducing total reflections between the light emission element 10 'and the air adjacent in the outer space in comparison with the known light module mentioned above.

The value of the refractive index for air HL is 1.0; for the material of the

Light emitting element 10 ', the value of the refractive index nj is typically between 1.0 and 1.5. Preferably, the optical structure 200 is designed such that the electrodes 21, 22 and / or the material 20 each have a refractive index ns, for which ni <ns <nj.

In Figures 3 a and 3b, a second Ausrahrungsbeispiel is sketched accordingly. In the following, only the differences from the first embodiment will be discussed. The reference numerals are used analogously.

In the second embodiment, trapezoidal elements are used as the optical elements 25 instead of the microlenses in cross section. Here, the optical elements 25 accordingly form prisms; the material 20 thus has one

Prismatic structure, in particular a Mifaoprismenstmktur on.

In this case, the directed orientation of the second electrode 22 leads to a convolution of the coupled-out light toward the flat edge of the trapezium a side lighting can be used. The optical elements 25 may, for example, also be formed by pyramidal elements or scattering centers.

In the figures 4a and 4b, a third Ausruhrungsbeispiel is sketched accordingly. Here, between the optical structure 200 and the light-emitting element 10 'is a further optical structure 30, for example in the form of a structured

Intermediate layer arranged. In this case, the first electrode 21 is not arranged directly on the light-emitting element 10 ', but-preferably directly-on the further optical structure 30 or the intermediate layer. In this way, a further reduction of the total reflections between the

Achieve light emitting element 10 'and the first electrode 21 and the layer or the material 20. As a result, the coupling of the light into the optical structure 200 can be improved, so that overall the efficiency of the lighting module can be increased further.

The further optical structure 30 may in particular be a lens structure or

Have microlens structure or consist of such.

A corresponding further optical structure 30 can also be used in conjunction with the first exemplary embodiment, that is to say with optical lenses designed as microlenses

Elements 25 or other optical elements (pyramids, scattering centers) are used.

Advantageously, the structure formed by the material 20 may be in

different areas or subregions of the surface 102 may be formed differently. For example, it may have microprisms in a first region of the surface 102 and micro-lenses in a second region or microprisms of a first orientation in a first region and microprisms of a second orientation in a second region which differs from the first orientation and the like. s. w. In this way, in particular very different directional properties of the light emitted by the light module can be effected.

The active or variable optical structure 200 may advantageously over the entire surface of the light module or over the entire surface 102 of the Light emitting element 10 'extend. Alternatively it can be provided that the active or variable optical structure 200 extends only over a partial area of the surface of the lighting module or only over a partial area of the surface 102 of the light emitting element 10 '. This also makes special

Light effects with the light module can be achieved. For example, in this way advantageous symbols u. s. w. represent.

FIGS. 5a and 5b show an embodiment with a further embodiment

In this case, the optical structure 200 is embodied such that the second electrode 22 extends only over part of the material 20, hereinafter referred to as "active region" 26. The described variable directional influence is therefore limited to the active region 26 in this case. In Fig. 6a is a corresponding plan view of the surface 102 of the

Light emitting element 10 'outlined. In this case, only one area of the surface 102 is provided with the second electrode 22, so that this area forms the active area 26. The remaining area of the surface 102 may, for example, be covered only with the first electrode 21 and the material 20, as shown by way of example in FIGS. 5a and 5b. As further indicated in FIGS. 5 a and 5 b, the material 20 may also have a microlens structure or other structure in the region not covered by the second electrode 22, so that a region which can not be influenced or changed by the voltage U is in this region optical effect can be achieved.

The second electrode 22 preferably extends for easier electrical contacting to the edge region of the surface 102. This may be configured, for example, by a corresponding "web" 28. Here, electrostatic forces are effective the variable voltage U is dominant, not one

Current transport. The latter can rather be negligible.

The web 28 is preferably designed such that the voltage drop across the web 28 is not greater than 10%. The width of the web 28 advantageously extends over at least three to five optical elements 25 to ensure a good continuous supply line.

As indicated symbolically in section in FIG. 6b, different emission characteristics can therefore be achieved in the different regions.

Another example is sketched accordingly in FIGS. 7a and 7b. Here, a subregion of the surface 102 is designed as an active region 26, although, for example, no micro-lenses, but microprisms are provided as optical elements 25. In this embodiment, the remaining area of the surface 102 may, for example, be formed without the optical structure 200, so that, viewed in plan view, the corresponding area of the surface 102 of the

Light emitting element 10 'can be seen. Alternatively, the remaining region can be covered, for example, with the further optical structure 30, which, of course, can also extend in the aforementioned sense over the active region 26, under the corresponding optical elements 25.

Claims

claims

1. Light module, comprising

a plate-shaped, active element (12),

a plate-shaped carrier element (10) having a surface (101) on which the active element (12) is arranged,

a transparent light-emitting element (10 ^' ), which is preferably through the

Carrier element (10) is formed,

characterized,

in that at least part of a surface (102) of the light-emitting element (10 ') is provided with an active or variable optical structure (200).

2. Light module according to claim 1,

characterized,

in that the active or variable optical structure (200) comprises two transparent electrodes (21, 22) and a material (20) located between the electrodes (21, 22), the structure of which depends on that between the electrodes (21, 22 ) applied voltage (U) changed.

3. Light module according to claim 2,

characterized,

in that the material (20) located between the electrodes (21, 22) is formed by an elastomer or acrylates.

4. light module according to claim 2,

characterized,

in that the material (20) located between the electrodes (21, 22) is formed by an amorphous fluoropolymer.

5. Light module according to one of claims 2 to 4,

characterized, in that the material (20) located between the electrodes (21, 22) has a structure.

6. lighting module according to claim 5,

characterized,

that the structure has a lens structure.

7. Light module according to claim 5,

characterized,

that the structure has a prismatic structure.

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

characterized,

that the structure is formed differently in different areas.

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

characterized,

in that the active or variable optical structure (200) extends over the entire surface of the lighting module.

10. Light module according to one of claims 1 to 8,

characterized,

the active or variable optical structure extends (200) only over a partial area of the surface of the lighting module.

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

characterized,

in that between the transparent light-emitting element (10 ') and the active or changeable optical structure (200) there is arranged another optical structure (30) which is not variable in terms of its properties.

12. Light module according to claim 11,

characterized, the further optical structure (30) has a lens structure.

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

characterized,

in that the light-emitting element (10 ') is formed by the carrier element (10) and / or by encapsulation (11) which is mounted on a carrier element (10).

opposite side of the active element (12) is arranged.

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

characterized,

the active element (12) is formed by an OLED or QLED structure.