EP2561387A1

EP2561387A1 - Surface light guide and planar emitter

Info

Publication number: EP2561387A1
Application number: EP11710188A
Authority: EP
Inventors: Peter Brick; Stephan Kaiser; Gerhard Kuhn; Ales Markytan; Julius Muschaweck; Christian Neugirg
Original assignee: Osram Opto Semiconductors GmbH
Current assignee: Ams Osram International GmbH
Priority date: 2010-04-23
Filing date: 2011-03-23
Publication date: 2013-02-27
Also published as: US20130114292A1; US8998479B2; WO2011131446A1; DE102010018033A1; KR20130060204A

Abstract

The invention relates to a surface light guide (1) which has a radiation exit area (10) extending along a main extension plane of the surface light guide (1) and is provided for laterally coupling radiation, wherein - the surface light guide (1) comprises scattering locations (4) for scattering the coupled radiation; - the surface light guide (1) comprises a first boundary surface (15) and a second boundary surface (16) which delimit the light conductance of the coupled-in radiation in the vertical direction; - and a first layer (11) and a second layer (12) are formed on each other in the vertical direction between the first boundary surface (31) and the second boundary surface (32). Further disclosed are a planar emitter (100) comprising at least one surface light guide (1).

Description

description

Surface light guide and surface radiator

The present patent application relates to a

Surface light guide and a surface radiator with at least one such surface light guide.

This patent application claims the priority of German Patent Application 10 2010 018 033.5, the disclosure of which is hereby incorporated by reference.

In conventional radiation sources, the generated

Radiation typically from a comparatively small area. An enlargement of this area can

for example, done by the Nachordnen a lens. However, this can be one over the

Radiation exit surface comparatively inhomogeneous

Lead luminance distribution.

One task is to achieve a large-area radiation with simultaneously high homogeneity. This object is achieved by a surface light guide having the features of patent claim 1. Embodiments and developments are the subject of the dependent claims.

In one embodiment, a surface light guide has a radiation exit surface extending along a main extension plane of the surface light guide, wherein the

Surface light guide for a lateral coupling of

Radiation is provided. The surface light guide points

Streets to scatter the coupled radiation. The surface light guide has a first interface and a second interface on which a light pipe of the coupled radiation in the vertical direction, ie in a direction perpendicular to the main plane of extension

Direction, limit. Between the first interface and the second interface, a first layer and a second layer are formed on each other in the vertical direction.

The surface light guide is preferably provided for coupling radiation with a first radiation component and with a second radiation component. These radiation components can be different from one another, for example with regard to the spatial coupling into the surface light guide or with regard to a peak wavelength.

By means of the first layer and the second layer, various light-guiding regions for the first radiation component and the second radiation component can be formed with regard to the scattering.

Further preferably, the first layer and the second layer are formed such that the first radiation component and the second radiation component homogeneous from the

Exiting radiation exit surface.

In other words, the scattering effect in the surface light guide can be set by means of the first layer and the second layer for the different radiation components. The

Coupled radiation can escape over a large area and at the same time with a high degree of homogeneity from the radiation exit surface.

The homogeneity relates in particular to the spatial homogeneity of the radiation exit surface emerging radiation and the homogeneity of the color locus of the radiated radiation as a function of the location on the

Radiation exit surface and / or the angle of radiation.

As a measure of the homogeneity of the color locus, for any two points on the radiation exit surface, the

Color locus for a given angle in the color diagram (CIE diagram) are plotted.

Preferably, these points are within a 5-step McAdam ellipse, more preferably within a 3-step McAdam ellipse.

At least one of the radiation components is preferably in the visible spectral range. In particular, the

Spectral components for generating mixed radiation, such as for the human eye white radiation appearing to be provided.

By means of the various light-guiding regions, the surface light guide can be designed so that the scattering effect in the light guide can be adapted to the respective radiation components. In particular, the first layer and the second layer may be formed such that a wavelength-dependent

Scattering is compensated at the individual Streustellen. In contrast, a conventional

Surface light guide on a single Lichtleitbereich in which propagate all radiation components, so that a

The wavelength-dependent scattering effect of the scattering sites causes the wavelength components for which the scattering effect is highest to emerge from the planar light guide with an increased probability. Under a lateral coupling is in doubt a

Coupling understood in the surface light guide, in which a main direction of the coupling along the

Main extension plane of the surface light guide takes place.

Further preferably, the surface light guide is such

designed so that it has a high transparency in the off state, so in the absence of a side-coupling radiation source. High transparency is understood in this context to mean that in the

Surface light guide the absorption and scattering of

Radiation is so low that the sum of specular

Reflectivity and specular transmission comes as close to the theoretical limit of 1. The transparency is preferably at least 60%, particularly preferably at least 80%.

In a preferred embodiment, the patches have an average extension which is at most 1.0 times, preferably at most 0.5 times, more preferably at most 0.3 times the peak wavelength of

coupled radiation in the surface light guide, so the vacuum wavelength divided by the refractive index of the material of the surface light guide is.

The spots are therefore preferably small compared to the wavelength of the radiation to be scattered. At such

Streeting is predominantly Rayleigh scattering. in the

Difference to riddling, which is big compared to the

Wavelength of the radiation, also occur in the Rayleigh scattering on large scattering angles, which leads to a total of high homogeneity of the angular distribution of the radiated radiation. For large sites, however, the scatter causes only a relatively small change in angle, causing the out of the

Radiation exit surface escaping radiation, especially at high angles, such as at angles of 50 ° or more to

Normal the radiation exit surface has high LEDs.

The first layer and the second layer are preferably designed to have a wavelength dependence of

Compensate scattering effect. In Rayleigh scattering, for example, the scattering effect is proportional to the fourth power of the frequency of the radiation to be scattered, so that, for example, blue radiation is scattered considerably more strongly than red radiation.

In principle, any form of refractive inhomogeneity that leads to the scattering of radiation in the desired spectral range is suitable for the work sites. For example, the spots may be in the form of particles, such as air-filled particles, cavities or defects in the surface light guide

be executed.

The first boundary surface and the second boundary surface define in the vertical direction the region of the surface light guide in which total reflection causes at least partial light transmission.

A "position" of the surface light guide is understood in particular to mean a region between the first boundary surface and the second boundary surface whose vertical extent is so great that it makes a significant contribution to the light transmission for at least one radiation fraction

Layers, such as layers, whose vertical extent is smaller or equal to the wavelength of the radiation coupled into the surface light guide, however, do not constitute a position in the sense of the present application.

Preferably, the first layer and the second layer

with respect to the scattering effect adapted to each one radiation fraction.

In order to adapt the layers to the respective radiation components, the layers may differ, for example, in one another from a concentration and / or a size and / or a size distribution and / or a material of the work sites. Alternatively or additionally, the first layer and the second layer can also be used with respect to the one used in each case

Base material to be different from each other.

In a first embodiment variant, the first layer and the second layer are decoupled from each other with respect to the light pipe.

According to at least one embodiment, the

Surface light guide for coupling radiation provided with a first radiation component and a second radiation component, wherein the radiation components with respect to a peak wavelength are different from each other. The first layer and the second layer are with respect to the light pipe

decoupled from each other. The first layer and the second layer are each with respect to the scattering effect

Radiation component adapted so that they have a

Compensate the wavelength dependence of the scattering effect.

"In terms of light conduction decoupled from each other" in this context does not mean that the layers are complete are optically separated from each other. Rather, they are

Lichtleitbereiche preferably designed so that the

Light conduction for the individual radiation shares each carried out in a separate Lichtleitbereich. In particular, the radiation coupled out of a layer can pass through at least one of the other layers before it leaves the radiation exit surface.

The first layer and the second layer are preferably designed such that a ratio of the first radiation component to the second radiation component via the

Radiation exit surface is homogeneous.

For a large white radiating

Radiation exit surface, the surface light guide

For example, have three layers that are responsible for the light transmission of radiation components in the red, green and blue

Spectral range are provided. Alternatively or additionally, a mixed radiation can be coupled into at least one layer.

An efficient decoupling of the first layer from the second layer can be achieved, for example, by

between the first layer and the second layer at least partially total reflection occurs, from the first layer in the direction of the second layer and vice versa.

In a preferred embodiment, at least in regions between the first layer and the second layer

Separating layer and / or arranged at least partially a gap. The separating layer preferably has one

Refractive index which is smaller than the refractive index of the first layer and the second layer. Decoupled layers in which in both directions, ie both of the First layer in the direction of the second layer as well as from the second layer in the direction of the first layer on a surface total reflection occurs, can be realized so simplified.

The separating layer may alternatively or additionally be formed as a coating which is at least for one

Radiation component is reflective. An optical separation between the first layer and the second layer is thus further simplified.

For the area-wise formation of a gap which is filled with a gas, such as air, for example

Spacer may be provided between the first layer and the second layer, for example in the form of elevations.

In a second embodiment variant, the first layer and the second layer form subareas of a light-guiding region, in which the first radiation component and the second component

Propagate radiation fraction.

The light pipe is thus for the first

Radiation component and the second radiation component in a common Lichtleitbereich, wherein the first layer and the second layer are formed such that the individual

Radiation shares of the individual sections

be influenced to different degrees. In other words, preferably at least one radiation component propagates in one of the layers to a greater extent than the other

Radiation component.

The first layer and the second layer suitably have refractive indices different from each other in this case on. The larger the difference between the refractive indices, the smaller the critical angle for total reflection. The larger this difference is, the greater is the proportion of that radiation which is completely reflected back when the radiation impinges at the interface with the optically thinner material.

In a preferred embodiment, the

Surface light guide on a further layer, which is arranged on the side facing away from the second layer of the first layer. Further preferably, the first layer has a higher refractive index than the second and as the further layer.

The first layer can thus be embedded between two layers which have a smaller refractive index, so that total reflection occurs on both sides of the first layer.

In a preferred development, a material of the first layer has a dispersion in the visible spectral range. Due to the dispersion, the

Radiation shares at the interfaces of the first layer each have different total reflection critical angle.

In a first variant, the material of the first layer has an anomalous dispersion. For example, anomalous dispersion causes the refractive index in the red

Spectral range is greater than in the blue spectral range. Due to the different angle for total reflection, the first layer acts as a light guide for a larger proportion of the radiation in the red spectral range than for the

Radiation in the blue spectral range. The first layer preferably has a higher concentration of spots than the second and the further layer. The second and / or the further position can be further developed also free of roadworks.

In a second variant, the material of the first layer has a normal dispersion. In this case propagates in the first layer predominantly the radiation with the shorter

Wavelength, for example blue radiation. For one

efficient decoupling of the radiation with the longer one

Wavelength, the patches are preferably arranged exclusively or at least with a higher concentration in the second and / or the third layer.

In both variants, the exposure sites are thus predominantly formed in that position in which predominantly propagates the radiation with the larger wavelength. So can the

Radiation components with different spectral components homogeneously emerge from the radiation exit surface.

The surface light guide can be provided for the one-sided or for the two-sided coupling.

In one embodiment, the surface light guide has a side facing away from the radiation exit surface

Structuring on.

The structuring can be provided in particular for a double-sided radiation decoupling

Shift the issue to the side of the

Radiation exit surface to effect. The structuring may have, for example, structural elements in the form of pyramids or hemispheres.

Furthermore, a structure size of the structuring is preferably smaller than the resolution capacity of the human eye. Thus it is achieved that the surface light guide despite the Structuring for the eye as a homogeneous,

unstructured surface appears.

In a further preferred embodiment, at least one layer of the surface light guide has an inhomogeneous distribution of the spots, such as a distribution with a plurality of maxima. By means of these local maxima, for example, spot-like radiation can occur on the radiation exit surface

Be formed areas in which the luminance is increased compared to the other areas.

The surface light guide described above is

in particular suitable for the formation of a surface radiator, wherein the surface radiator has at least one surface light guide and at least one radiation source, wherein the coupled during operation of the surface radiator in the surface light guide radiation is generated by means of the radiation source.

In a preferred embodiment, the radiation source has at least one semiconductor body with an active region provided for generating radiation. In a further preferred embodiment, the radiation source

at least one white light source. Furthermore, the

Radiation source having a light source in the green spectral range. The light source in the green spectral range can be provided, in particular, for compensating for, for example, aging, too low a green component of the white light source.

Further features, embodiments and expediencies will become apparent from the following description of

Embodiments in conjunction with the figures. Show it:

1 shows a surface radiator with a surface light guide according to a first embodiment in a schematic sectional view,

Figure 2 shows a surface radiator with a surface light guide according to a second embodiment in

schematic sectional view,

3 shows a surface radiator with a surface light guide according to a third embodiment in FIG

schematic sectional view,

FIG. 4 shows a surface radiator with a surface light guide according to a fourth exemplary embodiment in FIG

schematic sectional view,

FIG. 5 a surface radiator with a surface light guide according to a fifth exemplary embodiment in FIG

schematic sectional view,

FIG. 6 shows a surface radiator with a surface light guide according to a sixth exemplary embodiment in a schematic sectional view,

7 shows a surface radiator with a surface light guide according to a seventh embodiment in FIG

schematic sectional view,

8 shows a surface radiator with a surface light guide according to an eighth embodiment in a schematic sectional view. The same, similar or equivalent elements are provided in the figures with the same reference numerals.

The figures and the proportions of the elements shown in the figures with each other are not as

to scale. Rather, individual elements for better presentation and / or better

Understanding to be exaggeratedly tall.

FIG. 1 shows a surface radiator 100 which has a surface light guide 1. The surface light guide has a first layer 11, a second layer 12 and a further layer 13. The layers 11, 12, 13 are between a first

Interface 15 and a second interface 16 is formed. In the vertical direction, that is perpendicular to one

Main extension plane of the surface light guide 1, the boundary surfaces limit the area of the surface light guide in which the coupled radiation, in particular due to

Total reflection, propagated. In the layers 11, 12, 13 are scattered sites 4 are formed, which are for the dispersion of radiation, the side, ie along a main extension direction of the surface light guide in the surface light guide

is coupled, are provided. By means of the Streustellen 4 is the radiation component, which consists of a

Radiation exit surface 10 exits, increases.

The layers 11, 12, 13 are with respect to the light pipe

at least partially decoupled from each other. The

Decoupling takes place in each case by means of total reflection at the transitions between the first layer 11 and the second layer 12 or between the second layer and the further layer 13. Spacers 51 are arranged between the first layer 11 and the second layer 12, so that a gap 5 is formed in regions, which optically decouples the layers from one another.

As a further example of an optical decoupling, a separating layer 60, for example in the form of a coating, is formed between the second layer 12 and the further layer 13. The separating layer has a smaller one

Refractive index on than the second layer 12 and the further layer 13th

The separation layer 60 can furthermore be designed to be reflective for at least one radiation component, in order to provide the

Decoupling of the radiation by the

Radiation exit surface 10 to increase.

The separating layer preferably contains a dielectric material, which is furthermore preferably transparent to radiation in the visible spectral range. For example, an oxide, such as silicon oxide, or a nitride, for example, silicon nitride is suitable. The separating layer can also be designed as a multilayer.

The layers 11, 12, 13 each form for by a

Side surface 19 coupled radiation a separate

Lichtleitbereich, wherein the Lichtleitbereiche are each provided for different radiation components.

For example, the first blue radiation layer 11, the second green radiation layer 12 and the further red radiation layer 13 may be provided.

The layers 11, 12, 13 are formed with respect to the scattering effect such that the individual radiation components homogeneous the radiation exit surface 10 exit. In the embodiment shown, the adaptation of the layers to the respective radiation fraction by means of a variation in the concentration of the Streustellen 4. Alternatively or additionally, the adaptation of the layers 11, 12, 13 also by means of an adaptation of the material of the Streustellen 4 and / or the layers 11, 12, 13, carried out by means of the size of the Streustellen and / or the size distribution of the Streustellen.

The extent of the spots 4 is preferably small compared to the wavelength of the coupled radiation in the surface light guide first

Preferably, an average extent of the

At most 1.0 times, more preferably at most 0.5 times, most preferably at most 0.3 times the peak wavelength of the injected radiation. Rayleigh scattering occurs predominantly for such wavelengths, resulting in a homogeneous angular distribution of the luminance of the light emerging from the radiation exit surface 10

Radiation leads.

For any two points on the radiation exit surface, the associated color loci are in the color diagram (CIE diagram) for a given emission angle

preferably within a 5-step McAdam ellipse, more preferably within a 3-step McAdam ellipse. The

Radiation can therefore be characterized by a high degree of homogeneity with respect to the color locus.

The luminance for a given angle of radiation differs for any two points on the Radiation exit surface preferably at most by a factor of two.

A higher concentration of work sites 4 in the third layer 13 provided for the propagation of red radiation compensates for the lower one in this exemplary embodiment

Scattering effect of the spots compared to the shorter wavelength blue and green radiation. Despite the

Reduced scattering effect for the longer-wave radiation in the case of Rayleigh scattering is the coupling-out effect from the radiation exit surface 10 for the individual

Radiation shares from the respectively associated layer 11, 12, 13 approximately equal.

As a material for the surface light guide is suitable

for example, a glass or a plastic, for example polymethyl methacrylate (PMMA), polycarbonate (PC) or

Polyurethane (PU), whereby glass and PMMA are replaced by a

particularly high transparency.

The transparency of the surface light guide 1 according to the definition mentioned above is preferably at least 60%, particularly preferably at least 80%.

For example, particles which are embedded in the layers 11, 12, 13 are suitable as the workpieces 4. The particles may be solid or hollow,

for example as air-filled particles.

Even cavities or defects in the surface light guide can serve as a job site. Such cavities or defects are, for example, by targeted local evaporation of

Material of the surface light guide 1 produced. This can for example, thermally and / or optically, for example by means of

Laser radiation can be achieved.

With the described area radiator 100 can by means of the three radiation components in the red, green and blue

Spectral range for the human eye large-scale and homogeneous white appearing mixed radiation can be generated. However, this can be achieved deviating from the described embodiment, but with one of three different number of layers. For example, in only two layers, the first layer 11 for the coupling of red radiation and the second coupling 12 for mint-white appearing

Mixed radiation be provided.

Opposite a surface light guide, in which all

Propagate radiation components in a common Lichtleitbereich, is characterized by the described

Surface light guide 1 radiated radiation in particular by a particularly high homogeneity in the color space

at the same time high transparency when switched off. Over the radiation exit surface 10, the ratio of the radiation components to one another is therefore particularly homogeneous.

The area radiator 100 furthermore has a radiation source 2 on both sides of the surface light guide 1. The radiation source 2 comprises a first semiconductor body 20a for the generation of blue radiation, a second semiconductor body 20b for the generation of green radiation and a third semiconductor body 20c for the generation of red radiation, wherein in the semiconductor bodies each provided for generating radiation active region 21a, 21b, 21c is provided. The radiation source 2 has only one semiconductor body for each for the sake of simplicity

Spectral component on. Deviating from this, a multiplicity of semiconductor bodies, which can be arranged, for example, in a line-like or matrix-like manner, can also be provided.

Deviating from the radiation source, for example, the radiation source can also be designed as a gas discharge lamp.

A second exemplary embodiment of a surface radiator 100 with a surface light guide 1 is shown in FIG. The surface radiator 100 in turn has a

Surface light guide 1 and radiation sources 2, wherein the radiation coupling is effected by a side surface 19 which limits the surface light guide 1 in the main plane of extension. The surface light guide 1 has, between a first interface 15 and a second interface 16, a first layer 11 which is arranged between a second layer 12 and a further layer 13. In contrast to the first embodiment, the layers 11, 12, 13 form

Subregions of a common Lichtleitbereichs 17, in which the different radiation components of the

Radiation source 2 propagate generated radiation. The first layer 11 has a higher refractive index than the second layer 12 and the further layer 13, so that total reflection can occur at the transitions between these layers.

For the critical angle O ^ IR for total reflection, the relation eTIR ⁼ aresin (n2 / n] _) applies here, where Π] _ the refractive index of the first layer and r \ 2 den

Refractive index of the second layer represents. A corresponding relationship also applies to the further layer 13 with a refractive index 113.

From this it follows that the larger the fraction of the radiation for which total reflection occurs

Refractive index n _] _ relative to the refractive index ri2.

By means of the choice of the refractive indices, it is thus possible to set how large the proportion of the radiation propagating in the first layer due to total reflection is.

For example, for the first layer PMMA with a

Refractive index of about 1.5 and a glass with a

Refractive index between 1.4 inclusive and 1.48 inclusive apply.

For glass, the refractive index is adjustable between 1.4 and 1.9 by a suitable choice of composition. Furthermore, glass is distinguished from plastic by a higher optical stability and is easier to clean, so that glass is particularly suitable for the outer layers of the surface light guide.

In the exemplary embodiment illustrated in FIG. 2, the material of the first layer 11 exhibits anomalous dispersion in the visible spectral range, so that the refractive index is greater, for example, for long-wave red radiation than for shorter-wave blue radiation. For example, the first layer may comprise a fluorophosphate glass with anomalous dispersion. According to the above relationship, this causes the

Limit angle for total reflection for red radiation is smaller than for blue radiation. The blue radiation is therefore distributed more strongly in the light-guiding region 17 formed by the layers 11, 12, 13, while the red radiation remains to a greater extent in the first layer 11. to

Compensation of the wavelength-dependent scattering effect for Rayleigh scattering as described in connection with FIG. 1, the throwing sites 4 are formed in the first layer 11.

By contrast, the second layer 12 and the further layer 13 can be free of spots or at least have a lower concentration of spots than the first layer 11. By means of the second layer 12 and the further layer 13, blue radiation is thus produced for blue radiation in comparison with red radiation middle light path between the impact on the

Site 4 extended. This leads to a compensation of the more efficient scattering for blue radiation, so that the radiation emerging from the radiation exit surface 10 has a high homogeneity of the color locus.

The third exemplary embodiment shown in FIG. 3 essentially corresponds to the second exemplary embodiment described in connection with FIG. In contrast, the material for the first layer 11 has a normal dispersion. Thus, the blue radiation remains to a greater extent within the first layer 11 than the red radiation. In this case, to compensate for the

In the case of Rayleigh scattering, the scattering sites 4 may be formed in the second layer 12 and / or the further layer 13 as a function of the wavelength-dependent scattering effect. On the other hand, the first layer 11 may be free of spots or at least a lower one

Concentration at Streustellen exhibit. The illustrated in Figure 4 fourth embodiment of a surface radiator 100 with a surface light guide 1 substantially corresponds to the described in connection with Figure 2 second embodiment. In contrast, on the radiation exit surface 10th

side facing away from a reflector layer 7 is formed. The reflector layer is preferably designed to be broadband reflective. The reflector layer may, for example, contain a metal or a metallic alloy or consist of a metal or a metallic alloy.

For example, aluminum, silver and rhodium are characterized by a high reflectivity in the visible spectral range.

By means of the reflector layer 7 can from the

Radiation exit surface 10 facing away from the

Surface light guide 1 leaking radiation components in

Direction of the radiation exit surface are deflected and exit through this. The total exiting

Radiation power from the radiation exit surface can thus be increased.

Of course, the reflector layer described also for the in connection with the figures 1 and 3

described embodiments find application.

The illustrated in Figure 5 fifth embodiment corresponds substantially to the fourth embodiment. Deviating from this, instead of the reflector layer on the second boundary surface 16, a coating 6 is applied. The coating preferably contains a dielectric

Material, for example, one of the materials mentioned in connection with the release layer. Such, preferably multilayer, coating can be at least for one

Radiation share have a high reflectivity.

The illustrated in Figure 6 sixth embodiment of a surface radiator 100 with a surface light guide 1 substantially corresponds to the described in connection with Figure 2 second embodiment. In contrast, on the radiation exit surface 10th

opposite side of the surface light guide 1 a

Structuring 8 is formed. The structuring is formed in this embodiment by means of elevations 80 which are pyramid-shaped. Other shapes can be used for the surveys, for example, with a polygonal or at least partially curved cross section, such as hemispherical.

Alternatively or in addition to surveys may also

Find pits application. In the figure are to

Illustrating two possible ray trajectories, where the radiation is also visible without impinging on

Disconnecting sites is decoupled. The structuring 8 in this case promotes a deflection of the propagating radiation into small angles to the normal of the radiation exit surface.

Alternatively or additionally, the first layer 11, in particular on the side facing away from the radiation exit surface 10, may already be structured.

A structure size of the structuring 8 is preferably below the resolution of the human eye. For example, structures with a size of

below 30 ym from a distance of 10 cm from

human eye can not be resolved. Such Structuring is therefore perceived by the human eye as a homogeneous surface.

A seventh exemplary embodiment, which essentially corresponds to the first described in connection with FIG

Embodiment corresponds, is shown schematically in Figure 7. The representation is rotated in this figure by 90 °, so that the radiation of the radiation sources 2 is perpendicular to the plane of the drawing.

In contrast to the first embodiment, the

Surface light guide 1, a first layer 11 and a second layer 12, wherein the first layer and the second layer

differ in particular with regard to the distribution of the Streustellen 4. In the first layer 11, the spots have a uniform distribution in the context of statistical fluctuations

Distribution in the lateral direction. In contrast, the patches in the second layer 12 are targeted

unevenly distributed in a lateral direction. The distribution of the Streustellen 4 forms local maxima 41, which leads to a locally excessive scattering. The local maxima are strip-shaped. In the regions of the local maxima, this leads to increased radiation extraction from the radiation exit surface 10.

Such local maxima can be produced, for example, by using particles with a dipole moment, during which an electric field is applied.

From the radiation exit surface 10 thus occurs, on the one hand, a homogeneous resulting from the first layer 11

Radiation component and one of the second layer 12th

resulting inhomogeneous radiation component. One Area radiator 100 with such a surface light guide 1 is particularly suitable for effect lighting.

The inhomogeneity of the radiation component of the second layer 12 is determined by means of the position of the strips relative to

Radiation source adjustable. In the shown

Embodiment, the local maxima 41 are each offset to a main radiation direction of

Semiconductor body 20B of the radiation source 2 is arranged.

This increases the homogeneity of the radiation. However, such an offset can also be dispensed with in order to further increase the inhomogeneity of the radiation.

The semiconductor bodies 20a and 20b assigned to the respective layers 11, 12 can in this case be compared with respect to FIG

Emission spectrum similar, for example as

White light sources or different from each other.

In contrast to the first exemplary embodiment described in connection with FIG. 1, the surface light guide has a coating 6 on the radiation exit surface 10 which, as described in connection with FIG. 5, increases the radiation exit surface 10

resulting radiation component leads. On such a

However, coating can also be dispensed with, so that the surface light guide can be designed to emit light on both sides.

The eighth embodiment shown in Figure 8

corresponds essentially to the seventh embodiment described in connection with FIG. In contrast, in the first layer 11 and in the second layer 12, the work sites 4 are arranged evenly distributed. The Radiation source 2 has a white light source 23 and a light source 24 in the green spectral range.

The light source 24 is provided to the green portion of the total of the radiation exit surface 10

to influence exiting radiation. In particular, by means of the light source 24, an age-related degradation of the white light source 23, which leads to a decrease in the

Green component in the spectrum leads to be compensated.

Such a surface radiator 100 can thus be characterized by a higher constancy of the color location over its lifetime out.

The invention is not limited by the description with reference to the embodiments. Rather, the includes

Invention every new feature as well as every combination of

Features, which includes in particular any combination of features in the claims, even if this feature or this combination itself is not explicitly in the

Claims or the embodiments is given.

Claims

claims

1. Area light guide (1), one along a

Main extension plane of the surface light guide (1)

extending radiation exit surface (10) and is provided for a lateral coupling of radiation, wherein

- The surface light guide (1) has spots (4) for scattering the coupled radiation;

- The surface light guide (1) has a first interface (15) and a second interface (16), the light pipe of the coupled radiation in the vertical direction

limit; and

between the first interface (15) and the second

Boundary surface (16) in the vertical direction, a first layer (11) and a second layer (12) are formed on each other.

2. Surface light guide according to claim 1,

wherein the patches have an average extension which is at most 1.0 times a peak wavelength of the injected radiation in the surface light guide.

3. A surface light guide according to claim 1 or 2,

the for coupling of radiation with a first

Radiation component and a second radiation component

is provided.

4. surface light guide according to claim 3,

in which the first layer and the second layer are formed such that a ratio of the first radiation component to the second radiation component is homogeneous across the radiation exit surface.

5. A surface light guide according to claim 3 or 4,

wherein the first layer and the second layer with respect to

Lichtleitung are decoupled from each other.

6. surface light guide according to claim 5,

wherein the first layer and the second layer with respect to

Scattering effect are adapted to each radiation fraction.

7. surface light guide according to claim 5 or 6,

wherein between the first layer and the second layer, a release layer (60) and / or a gap (5) is arranged.

8. surface light guide according to claim 3 or 4,

wherein the first layer and the second layer form subregions of a light guide region (17), in which the first one

Propagate radiation component and the second radiation component.

9. A surface light guide according to claim 8,

wherein the surface light guide has a further layer (13) which is arranged on the side facing away from the second layer of the first layer, and wherein the first layer has a greater refractive index than the second and the further layer.

10. A surface light guide according to claim 9,

being a material of the first layer in the visible

Spectral region has an anomalous dispersion and the first layer has a higher concentration of work sites than the second and the further layer.

11. A surface light guide according to claim 9,

being a material of the first layer in the visible

Spectral region has a normal dispersion and the first layer has a lower concentration of sites than the second and the further layer.

12. A surface light guide according to any one of claims 1 to 11, wherein the surface light guide on the

Radiation exit surface facing away from a

Structuring (8).

13. surface radiator (100) with at least one

Surface light guide (1) according to one of claims 1 to 12 and at least one radiation source (2), wherein the radiation coupled into the surface light guide during operation of the surface radiator is generated by means of the radiation source.

14. Surface radiator according to claim 13, wherein the

Radiation source has at least one semiconductor body (20, 20A, 20B, 20C) with an intended for the generation of radiation active region (21, 21A, 21B, 21C).

15. Surface radiator according to claim 13 or 14,

in which the radiation source has a white light source (23) and a light source (24) in the green spectral range.