DE102008055714B4 - Semitransparent lighting device - Google Patents

Abstract

A lighting device comprising: a luminescent layer (120), a shielding layer (130) of an opaque material disposed between a backside of the lighting device and the luminescent layer (120), and a plurality of transparent hole areas (140) to which the luminescent layer (120) and the shielding layer (130) are perforated and which extend between the rear side and a front side of the lighting device, the shielding layer (130) each having edge regions (132) formed around the hole regions (140) and projecting beyond the luminescent layer (120) Preventing radiation of light toward the back of the lighting device so that light is radiated unilaterally toward the front of the lighting device, with the hole areas (140) being irregularly arranged in the plane of the shielding layer (130).

Description

The present invention relates to a planar semitransparent lighting device with single-sided radiation characteristic.

Numerous electrically powered radiation sources are known for illuminating objects, e.g. Incandescent lamps, arc lamps, lasers, LEDs (LED: "Light Emitting Diode") and OLEDs (OLED: "Organic Light Emitting Diode"). To obtain areal illumination, most of the radiation sources mentioned must be combined with a homogenizing or scattering optic (for example diffuser). Only the OLED has a priori the property to radiate areally and homogeneously from a very thin layer.

The usual structure of OLEDs is that a substrate with a transparent conductor layer, e.g. indium tin oxide (ITO). The transparent wiring layer is followed by a hole line layer, a luminescent layer containing small organic molecules or polymers, an electron conductive layer, and a low workfunction metal cathode layer. When an electric current flows through these layers, the luminescent layer, which is typically only about 200 nm thick, emits radiation. This radiation is usually in the visible spectral range, but may also have shares in the ultraviolet or infrared spectral range.

Further developments of OLEDs aim to replace the relatively expensive ITO layer with other transparent and simultaneously conductive materials. It has been found that, for example, gold nanowires are in principle suitable for this purpose.

Furthermore, it is also known that the luminous surface of an OLED can be structured. For this purpose, it is possible, for example, to use shadow masks when evaporating the OLED layers. For polymer OLEDs, printing processes can be used for structuring.

A distinction can be made between two basic types of OLEDs. In one design, one electrode layer is transparent (e.g., ITO) while the other is an untransparent metallic layer. In this design, the radiation generated by the OLED is emitted only on one side through the transparent electrode layer. Accordingly, this design is also impermeable to other light.

In the second design, both electrode layers are transparent, for example made of ITO. Here, the OLED radiates from both sides, and it is also permeable to other light. However, imaging through such an OLED is only possible to a limited extent because the two-sided radiation causes dazzling of the detector (for example camera or eye). At least a significant decrease in contrast is to be expected when the OLED radiates in the direction of the detector.

From the US 2006/0202104 A1 a monolithic image sensor is known which can be provided with a monitranslucent semitransparent luminescent layer. The unilaterally radiating semitransparent luminescent layer can be implemented on the basis of LEDs or OLEDs. The luminescent layer contains on one side a metallic contact layer. Holes formed in the luminescent layer allow the passage of light to an image receiving layer. However, even in this known lighting device, light generated in the luminescent layer may be scattered through the holes in the direction of the image-capturing layer. This problem is exacerbated when the proportion of holes in the total area of the luminescent layer is increased to achieve improved transparency. There is a need, therefore, for single-sided radiating semitransparent lighting devices that allow for improved separation of the generated light and the transmitted light.

The DE 10 2004 016 627 A1 describes a display device having a plurality of pixels based on a light-emitting layer. Conductor tracks are arranged on one side of the light-emitting layer, some of which project laterally beyond the light-emitting layer.

The EP 1 724 631 A1 describes a lighting section of a reflective liquid crystal display device whose layer structure comprises a luminescent layer and a cathode layer arranged above the luminescent layer.

An object of the present invention is to provide a lighting device which has improved suitability for image capture through the lighting device.

This object is achieved by a lighting device according to claim 1. The dependent claims define advantageous embodiments of the invention.

According to the present invention, a lighting device comprises a luminescent layer and a shielding layer disposed between the back of the lighting device and the luminescent layer of an opaque material. Furthermore, a plurality of transparent hole areas is provided which extend between the Rear side and a front side of the lighting device by the light-emitting layer and the shielding layer extend. The luminescent layer and the shielding layer are thus broken at the hole areas. The shielding layer has respective edge regions formed around the hole regions, the edge regions projecting beyond the luminescent layer. Preferably, the edge regions protrude beyond the luminescent layer by at least one micrometer. The hole areas can have any suitable shape in cross-section, for example round, oval, rectangular, triangular, polygonal or strip-like. The extension of the hole areas in the plane of the shielding layer is 500 μm or less in at least one direction. The hole areas are arranged irregularly in the plane of the shielding layer. This may be advantageous in certain applications to reduce moiré effects. Furthermore, it is also not necessary that the hole areas each have the same shape and size. Using different shapes and sizes for the hole areas can also help reduce moiré effects.

In the lighting device according to the invention, light is emitted on one side in the direction of the front side of the lighting device. The shielding layer prevents radiation of light towards the back of the lighting device. In particular, the edge regions which project beyond the luminescent layer prevent light generated by the luminescent layer from being emitted or scattered in the direction of its rear side within the illumination device. This advantage is maintained even if the proportion of the hole areas on the total area of the luminescent layer is relatively high, e.g. 50% or more.

According to one embodiment, shielding walls of an untransparent material are formed around the hole areas. The shielding walls may extend substantially perpendicular to the shielding layer and the luminescent layer. The shielding walls are formed along a part of the hole portions between the shielding layer and the front side of the lighting device. The shielding walls may be connected to the shielding layer. The shielding walls preferably extend between the luminescent layer and the hole regions. In particular, the shielding walls can extend beyond the luminescent layer in the direction of the front side of the lighting device. A height of the shielding walls along the axis of the hole regions is preferably greater, the greater the width of the luminescent layer enclosed between two adjacent hole regions. The height of the shielding walls can be selected, for example, depending on the width of the enclosed luminescent layer in a range between 10 .mu.m and 500 .mu.m. The shielding layer and / or the shielding walls can be designed to be reflective. However, it is also possible for the side of the shielding walls facing the luminescent layer or the side of the shielding walls facing the hole areas to be designed to be absorbent.

By means of the shielding walls, beam traps are formed around the luminescent layer, which enable an effective suppression of the scattering or radiation of light generated in the luminescent layer in the direction of the rear side of the lighting device.

According to a further preferred embodiment, the lighting device comprises at least one further luminescent layer, which is arranged between the luminescent layer and the front side of the lighting device. The further luminescent layer is made of a transparent material. By way of example, the further luminescent layer may be an OLED luminescent layer. In this embodiment, the luminous regions also extend through the further luminous layer or through the further luminous layers, and shielding walls are provided, which extend between the further luminous layer and the hole regions, so that beam traps are also formed around the further luminous layer or around the further luminous layers are.

In addition, the lighting device may comprise one or more antireflection layers. For example, an antireflection layer may be arranged on the front side of the illumination device. In addition, an internal antireflection layer can be formed between each luminescent layer and the front side of the illumination device. In addition, an antireflection layer can also be provided on the back of the lighting device. The antireflection layers may include, for example, the dielectric multilayers or moth-eye structures. The antireflection layers preferably have a reflectivity of less than one percent in the visible spectral range.

In a further preferred embodiment, a transparent protective layer is arranged on the front side of the lighting device. The transparent protective layer may be, for example, a thin cover glass plate. The transparent protective layer protects the luminescent layer from harmful external influences, eg mechanical damage or chemical aging. In addition, the radiation behavior of the lighting device can be specifically improved by the protective layer. For example, the protective layer may be configured such that at the Outside of the protective layer inwardly reflected light from the luminescent layer remains trapped due to total reflection in the lighting device.

Moreover, in a preferred embodiment, a plurality of microlenses may be disposed on the front of the illumination device. The microlenses can prevent light from the luminescent layer, which is reflected inwardly at the front side of the lighting device, from being directed in the direction of the hole regions. For this purpose, the microlenses are preferably located between the hole areas, i. in front of the regions of the luminous layer formed between the luminous areas. Furthermore, a targeted beam deflection, in particular focusing, of the light emitted from the illumination device can be achieved by the microlenses. In this way, for example, the irradiance in an object plane can be partially increased.

The illumination device can be produced by a layer structure on a transparent back substrate. However, it may also be provided separate intermediate substrates, which are attached to a carrier substrate. For example, such intermediate substrates may be configured as a perforated plate, which is perforated at the positions of the hole areas. The luminescent layer and / or a further luminescent layer can then be applied to the surface of the perforated plate. The inner walls of the hole areas formed in the perforated plate may be coated to form the shielding walls.

The substrates used in the lighting device may be planar or have curved surfaces. For example, the layers of the illumination device can be applied to a curved surface of a lens. In this case, the lens would constitute a support substrate for the lighting device. Furthermore, the lighting device can also be constructed on the basis of deformable substrates.

The luminescent layer and / or the further luminescent layers may each be formed as a coherent luminescent layer. Alternatively, a plurality of luminous regions can be formed, which can be controlled separately. In this case, a targeted activation of the separate lighting areas is possible in order to achieve lighting with controllable area-like patterns.

The lighting device according to the invention can be advantageously used for a large number of applications. For example, the illumination device according to the invention may be provided in an optical device, for example in an endoscope, a microscope, a magnifying glass, a pair of glasses, a lens, a camera, e.g. a photographic camera, a movie camera or a video camera, a display device, a copier or a scanner. In this case, the illumination device may be applied to an optical element of the optical device. The optical element may be a transmissive imaging element, e.g. a lens, a reflective imaging element, e.g. a semitransparent mirror, or a beam splitter element. In addition, the lighting device may be part of a watch glass, a display case, a cabinet, an aquarium or a terrarium. Furthermore, the illumination device can be part of a picture frame. The lighting device may also be part of a refrigerator or freezer or a window pane to a neighboring room. The illumination device can serve to illuminate a reflective display device or be used for incident illumination for a matrix-like arrangement of miniature lenses.

When the illumination device is applied to a specular optical element, better beam shaping can be achieved for different illumination arrangements. Furthermore, the use of the lighting device is made possible in hybrid lenses. When using the illumination device as part of a beam splitter element, applications are possible which combine incident-light fluorescence microscopy techniques with a dimmable incident-light / bright-field microscopy method, i. in a multimodal microscopy method.

• 1 veranschaulicht schematisch eine Beleuchtungsvorrichtung gemäß einem Ausführungsbeispiel der Erfindung.
• 2 zeigt eine schematische Draufsicht der Beleuchtungsvorrichtung von 1.
• 3 veranschaulicht schematisch eine Beleuchtungsvorrichtung gemäß einem weiteren Ausführungsbeispiel der Erfindung.
• 4 veranschaulicht schematisch eine Beleuchtungsvorrichtung gemäß einem weiteren Ausführungsbeispiel der Erfindung.
• 5 veranschaulicht schematisch eine Beleuchtungsvorrichtung gemäß einem weiteren Ausführungsbeispiel der Erfindung.
• 6 zeigt schematisch eine Draufsicht von in der Beleuchtungsvorrichtung von 5 verwendeten Zwischensubstraten.
• 7 veranschaulicht schematisch eine Beleuchtungsvorrichtung gemäß einem weiteren Ausführungsbeispiel der Erfindung.
• 8 veranschaulicht schematisch eine optische Einrichtung in Form einer Brille mit einer erfindungsgemäßen Beleuchtungsvorrichtung.
• 9 veranschaulicht schematisch eine optische Einrichtung in Form eines Objektivs mit einer erfindungsgemäßen Beleuchtungsvorrichtung.
• 10 veranschaulicht schematisch eine optische Einrichtung in Form einer Abbildungsoptik mit einer erfindungsgemäßen Beleuchtungsvorrichtung.
• 11 veranschaulicht schematisch eine optische Einrichtung in Form eines Mikroskops mit einer erfindungsgemäßen Beleuchtungsvorrichtung.

The invention will be explained in more detail below with reference to the accompanying drawings with reference to embodiments.

• 1 schematically illustrates a lighting device according to an embodiment of the invention.
• 2 shows a schematic plan view of the lighting device of 1 ,
• 3 schematically illustrates a lighting device according to another embodiment of the invention.
• 4 schematically illustrates a lighting device according to another embodiment of the invention.
• 5 schematically illustrates a lighting device according to another embodiment of the invention.
• 6 schematically shows a plan view of in the lighting device of 5 used intermediate substrates.
• 7 schematically illustrates a lighting device according to another embodiment of the invention.
• 8th schematically illustrates an optical device in the form of glasses with a lighting device according to the invention.
• 9 schematically illustrates an optical device in the form of a lens with a lighting device according to the invention.
• 10 schematically illustrates an optical device in the form of an imaging optics with a lighting device according to the invention.
• 11 schematically illustrates an optical device in the form of a microscope with a lighting device according to the invention.

In the following description of embodiments, reference is made to the accompanying drawings in which like or similar elements are designated by the same reference numerals throughout. A repeated description of these elements will be omitted. It is understood that the structures illustrated in the drawings are not to scale. In particular, layer thicknesses can be exaggerated for reasons of clarity.

1 schematically illustrates a lighting device. The lighting device comprises a transparent back substrate 110 , The transparent back substrate 110 may for example consist of glass, crystal, ceramic or plastic. On the back substrate 110 applied is a luminescent layer 120 , which is designed as an OLED luminescent layer. However, there are also other embodiments of the luminescent layer 120 possible, for example as an inorganic LED luminescent layer.

The luminescent layer 120 is periodically structured by being in the luminescent layer 120 a periodic grid of hole areas 140 is trained. The picture of 1 shows a cross section through the hole areas 140 and between the hole areas 140 trained webs of the luminescent layer 120 ,

The luminescent layer 120 is at least over some periods of structuring, for example, five or more periods, formed contiguous. In this way, for the contiguous areas of the luminescent layer 120 only one electrical contact via an anode layer and a cathode layer (not shown) is required. It is understood that the entire luminescent layer 120 can be configured as a single contiguous luminous area. In a division into several contiguous luminous areas of the luminescent layer 120 may be provided a separate electrical control of the individual lighting areas, for example, to be able to control the generation of different areal illumination patterns.

The luminescent layer 120 is provided on one side with a transparent electrode layer, so that on this side in the luminescent layer 120 generated light can be emitted in the direction of a front side of the lighting device. The transparent electrode layer may consist of ITO or another transparent and electrically conductive material, eg gold nanowires. On the other side of the luminescent layer 120 can also be formed a transparent electrode layer.

On the other side of the luminescent layer 120 that is, the side facing a back side of the lighting device is a shielding layer 130 formed of an untransparent material. At the in 1 The example illustrated is the luminescent layer 120 directly on the shielding layer 130 educated. The shielding layer 130 prevents from the luminescent layer 120 generated light is emitted in the direction of the back of the lighting device. It is understood, however, that the shielding layer 130 also between the luminescent layer 120 and the front of the lighting device could be arranged so that in the luminescent layer 120 generated light can be emitted only in the direction of the back of the lighting device. However, in the following only the case of a release of the in the luminescent layer 120 generated light are viewed in the direction of the front of the lighting device.

The shielding layer may be a metallic electrode which controls the luminescent layer 120 serves. In order to avoid reflections on the metallic electrode, in this case, between the luminescent layer 120 and the back substrate 110 may be incorporated with an absorbing layer and / or an anti-reflection layer. The absorbing layer may contain, for example, nanoparticles.

Between the luminescent layer 120 and the front of the lighting device is further a transparent protective layer 150 applied. The protective layer 150 For example, it may be a thin glass plate, a vapor deposited oxide layer, or a thin polymer layer. Through the protective layer 150 becomes the luminescent layer 120 protected against aging processes such as oxidation and mechanical damage. Especially in the case of a protective layer formed as a glass plate or polymer layer 150 can be between the protective layer 150 and the luminescent layer 120 are air, a protective gas or a polymer-based embedding medium, for example transparent adhesive.

In order to avoid that light generated in the luminescent layer by reflection on or in the protective layer 150 in the direction of the back substrate 110 to be scattered, is the protective layer 150 preferably with an antireflection layer 155 Mistake. For the anti-reflective coating 155 is a reflectivity of well below one percent in the visible spectral range preferred.

Furthermore, on the back of the lighting device, ie on the surface of the rear substrate 110 , an antireflection coating 115 be provided. In this way, the total transmission by the lighting device can be increased. In the antireflection layers 115 . 155 these may be, for example, the dielectric multilayers or moth-eye structures.

At the in 1 As a result, the transparent hole areas extend 140 between the front and the back of the lighting device. The hole areas 140 extend substantially perpendicularly through the luminescent layer 120 and the shielding layer 130 , The structuring of the luminescent layer 120 and the shielding layer 130 is therefore substantially congruent, whereby specific deviations can be introduced, which are explained in more detail below.

As already mentioned, should by the shielding 130 avoided that in the luminescent layer 120 generated light is emitted in the direction of the back of the lighting device. For this reason, the shielding layer 130 each around the hole areas 140 a border area 132 on, which over the luminescent layer 120 protrudes. Preferably, the edge region protrudes 132 by at least a micrometer over the luminescent layer 120 out. Typically, the width of the border area 132 greater than the thickness of the luminescent layer 120 , If, for example, the luminescent layer 120 only a few hundred nanometers thick, a few microns across the luminescent layer 120 Outstanding edge region 132 can be selected. An excessively wide width of the border area 132 however, should be avoided around the transparent hole areas 140 not to reduce unnecessarily.

In 1 is the light generated by the lighting device schematically by solid arrows 20 shown. The light emitted by the illumination device impinges on an object plane, which is typically at a distance from the illumination device 50 and is scattered or reflected there. That of the object plane 50 outgoing scattered or reflected light is in 1 by dashed arrows 30 illustrated. It can be seen that due to the hole areas 140 in the lighting device, the reflected or scattered light 30 is transmitted in the direction of the back of the lighting device.

Although in 1 the back substrate 110 and the layers of the illumination device formed thereon are shown as planar, it is understood that a curved or deformable structure may also be provided.

2 schematically shows a plan view of the lighting device of 1 , One of the luminescent layer 120 occupied area is shown hatched. Furthermore, they are around the hole areas 140 trained edge areas 132 the shielding layer 130 to recognize.

As in 2 are shown, the transparent hole areas 140 non-contiguous and square in shape. However, there are other cross-sectional shapes for the hole areas 140 possible, eg round, oval, rectangular, triangular, polygonal or strip-shaped. Furthermore, it is also conceivable that a hole area 140 in the plane of the luminescent layer 120 has a different cross-sectional shape than in the plane of the shielding layer 130 as long as the entire hole area 140 the over the luminescent layer 120 protruding edge area 132 results. In such a case, the border area would 132 typically one along the perimeter of the hole area 140 have varying width.

Furthermore, in 2 to realize that the hole areas 140 in the plane of the shielding layer 130 as well as in the plane of the luminescent layer 120 arranged in a regular square grid. However, other arrangements are possible, for example, a rectangular grid in which a distance between adjacent hole areas 140 in a first direction is different than a distance of adjacent hole areas 140 in a second direction, a hexagonal grid or an irregular or stochastic arrangement. An irregular arrangement may be advantageous, for example, to reduce the occurrence of moire effects. Furthermore, the transparent hole areas must 140 not all formed with the same cross-sectional shape or size. A variation of cross-sectional shapes or sizes can also be used to reduce moiré effects.

The distance of the hole areas 140 may be selected in the range of about 0.5 μm to 10 mm. In certain applications, however, it is preferred that the structuring is visually not or hardly noticeable. In this case, the distance between the transparent hole areas 140 less than 500 microns, in particular less than 100 microns.

In addition, the proportion of hole areas 140 on the total area of the luminescent layer 120 ie including the transparent hole areas 140 to be selected in a wide range. This proportion determines the transmission of light through the lighting device. The proportion of hole areas 140 on the total area of the luminescent layer 120 can be between 5% and 95%. In order to achieve a relatively high transmission, the proportion of hole areas 140 on the total area, preferably at 50% or more.

The lighting device can also be designed such that the of the luminescent layer 120 emitted radiation on the outer surface of the transparent protective layer 150 is reflected due to total internal reflection in the composite of back substrate 110 and transparent protective layer 150 remains trapped. In this way it can additionally be avoided that of the luminescent layer 120 generated radiation is scattered within the lighting device in the direction of the back of the lighting device and discharged on the back of the lighting device. For this purpose, the transparent protective layer 150 made of a material having a specific refractive index of preferably n> 1.5, wherein the back substrate 110 also has the specific refractive index of preferably n> 1.5. The transparent protective layer can be configured, for example, as a thin cover glass plate. That of the luminescent layer 120 generated light which on the outer surface of the transparent protective layer 150 can then be reflected by total reflection in the composite of back substrate 110 and transparent protective layer 150 being held. It is advantageous in that case between the transparent protective layer 150 and the back substrate 110 a medium, eg optical cement, which has a similar refractive index as the transparent protective layer 150 and the back substrate 110 , In this case, no light on the back of the lighting device from the back substrate 110 emerge at an angle to the solder of the outer surface of the back substrate 110 which is larger than a critical angle determined by the total reflection angle. When selecting a refractive index of n> 1.5 for the back substrate 110 and for the transparent protective layer 150 and assuming air as the surrounding medium, this critical angle is 42 °. At the outer edges of the illumination device, absorbent layers may be applied as jet traps. Will light from the luminescent layer 120 radiated and from the outer surface of the transparent protective layer 150 reflected so that it passes through the hole areas 140 is transmitted in the direction of the back of the illumination device, this light has an angle which is formed by the distance of the outer surface of the transparent protective layer 150 to the luminescent layer 120 and the width of the border areas 132 around the hole areas 140 results. If this angle is greater than the limit angle for the total reflection, the light can not come from the back substrate 110 escape. In this case, it would also be possible to dispense with an antireflection coating of the transparent protective layer 150. For example, when using a transparent protective layer 150 with a thickness of 30 microns, assuming a critical angle for the total reflection of 42 ° no light will be transmitted through the outer surface of the back substrate 110 when the edge regions 132 around the hole areas 140 have a width of more than 40 microns.

The border areas 132 On the front side of the illumination device facing side are preferably designed with an absorbent surface, so that in the direction of the back of the illumination device reflected or scattered light from the luminescent layer 120 not by multiple scattering or reflection through the hole areas 140 can get in the direction of the back of the lighting device.

3 illustrates another lighting device. The lighting device of 3 is essentially the same as that of 1 and 2 , wherein like or similar elements have been designated by the same reference numerals. With regard to the properties of these elements, the description is attached 1 and 2 directed.

In the lighting device of 3 the suppression of light emitted toward the back of the lighting device has been further improved. This improvement is based on the measure that the hole areas 140 shielding walls 135 are formed of an untransparent material. The shielding walls 135 extend from the shielding layer 130 towards the front of the lighting device and are in the plane of the luminescent layer 120 between the luminescent layer 120 and the hole areas 140 arranged. As shown, is a height of the shielding walls 135 chosen so that they are above the luminescent layer 120 extend beyond.

Through the shielding walls 135 , which with the shielding layer 130 are connected around the luminescent layer 120 Beam traps formed. The beam traps effect that at large angles to the surface normal of the luminescent layer 120 radiated light on the shielding walls 135 meets and is absorbed, scattered or reflected there. It avoids that from the luminescent layer 120 generated light in the area of the hole areas 140 on the protective layer 150 meets and is reflected from there towards the back of the lighting device. For this purpose, the shielding walls extend 135 preferably up to the protective layer 150 ,

The height of the shielding walls 135 is preferably dependent on the extent of the luminescent layer 120 between the shielding walls 135 selected. For example, is between two adjacent hole areas 140 the width of the luminescent layer 120 about 50 microns, is preferably a height for the shielding walls 135 chosen in the range between about 100 and 500 microns.

The shielding walls 135 can be prepared by various methods known in the microstructure technique, e.g. B. embossing, injection molding, gluing, etc. In addition, known coating techniques, such as vapor deposition, sputtering, chemical coating, etc., are used. Preferably, the hole areas are formed in an intermediate substrate of transparent plastic, which is easy to pattern.

Furthermore, at the in 3 illustrated illumination device microlenses 160 applied to the front of the lighting device. In particular, the microlenses 160 on the surface of the protective layer 150 educated. As in 3 shown are the microlenses 160 arranged such that the front of between the hole areas 140 lying areas of the luminescent layer 120 are arranged. If like in 2 represented the luminescent layer 120 lattice-like, resulting for the microlenses 160 lattice-like coherent cylindrical lens structures.

The expansion of the microlenses is preferred 160 along the plane of the luminescent layer 120 chosen larger than the extent of the luminescent layer 120 between two adjacent hole areas 140 ,

By means of the microlenses 160 becomes the portion of the light reflected on the outer surface of the protective layer 150 in the luminescent layer 120 generated light predominantly back towards the luminescent layer 120 reflected. This portion of the reflected light is in 3 schematically by a dashed arrow 20 ' shown. It is thus avoided that on the outer surface of the protective layer 150 reflected light through the hole areas 140 comes in the direction of the back of the lighting device.

Furthermore, by the microlenses 160 that of the luminescent layer 120 deflected light and focused, whereby the illuminance can be adjusted in the object plane. For example, the illuminance in the object plane can be partially increased.

The microlenses 160 can also be prepared by known methods of microstructure technology. It is understood that, in addition, an anti-reflection layer on the protective layer 150 and may be formed over the outer surface of the microlenses 160.

4 schematically illustrates another lighting device. The lighting device corresponds in many ways to the in 1 - 3 illustrated lighting devices. In 4 are elements similar to those of 1 - 3 are denoted by the same reference numerals. Its properties are related to the explanations 1 - 3 directed.

At the in 4 illustrated lighting device is in addition to the luminescent layer 120 another luminescent layer 125 intended. The further luminescent layer 125 is made of a transparent material. In particular, the further luminescent layer 125 be designed as an OLED luminous layer.

The luminescent layer 120 and the further luminescent layer 125 are through an intermediate substrate 170 spatially separated from each other. The hole areas 140 extend through the intermediate substrate 170 and the further luminescent layer 125 , so that in turn between the front and the back of the lighting device transparent hole areas 140 are formed, which is through the luminescent layer 120, the further luminescent layer 125 and the shielding layer 130 extend. In the area of the intermediate substrate 170 correspond to the hole areas cavities, which may be filled with air, another gas or a transparent material. The shielding walls 135 are applied to the inner surfaces of the cavities formed in the intermediate substrate 170 by suitable coating techniques. As shown, the shielding walls 135 between the luminescent layer 120 and the hole areas 140 and between the further luminescent layer 125 and the hole areas 140 arranged so that beam traps for both of the luminescent layer 120 generated light as well as that of the other luminescent layer 125 generated light are formed. The shielding walls 135 and the shielding layer 130 can on their respective the luminescent layer 120 or the further luminescent layer 125 facing sides to be configured reflective. This way can be an improved Yield of the luminescent layer 120 and the further luminous layer 125 emitted light can be achieved.

The shielding walls 135 preferably extend perpendicular to the luminescent layers 120 . 125 , but also within certain limits an angle deviating from 90 ° with respect to the luminescent layers 120 . 125 exhibit.

In 4 is that of the luminescent layer 120 emitted light schematically by solid arrows 20 while the light emitted by the further luminous layer 125 is schematically represented by dashed arrows 25 is shown. That from the object level 50 backscattered or reflected light is schematically indicated by dash-dotted arrows 30 shown.

At the in 4 The illumination device shown becomes light from the luminescent layer 120 delivered in the direction of the front of the lighting device. That of the luminescent layer 120 emitted light radiates through the further luminescent layer 125 and is emitted from the lighting device in the direction of the object plane 50.

The further luminescent layer 125 emits light both in the direction of the front of the lighting device and in the direction of the back of the lighting device. By reflecting surfaces behind the first luminescent layer 120 and on the screen walls 135 can that from the other luminescent layer 125 however, light finally leaves the lighting device only in the direction of the front side of the lighting device.

By using the further luminescent layer 125 is a significant increase in the radiated light output possible. This is a great advantage for many applications, especially if both the luminescent layer 120 as well as the further luminescent layer 125 are implemented as OLED luminescent layers, which compared to other light sources, such as LEDs or incandescent lamps, have a comparatively low luminance, which can be compensated by the use of multiple parallel luminescent layers.

5 schematically illustrates another lighting device. The lighting device of 5 corresponds in many ways to the in 1 - 4 illustrated lighting devices. In 5 are elements which are those of 1 - 4 correspond, denoted by the same reference numerals. Regarding the characteristics of these elements is related to the corresponding description 1 - 4 directed.

The lighting device of 5 is designed as a two-stage lighting device, which is a first luminescent layer 120 and a first further luminescent layer 125 which has the luminescent layers 120 . 125 the lighting device of 4 correspond. In addition, however, is still a second additional luminescent layer 126 provided, which of the first further luminescent layer 125 through another intermediate substrate 190 and spatially separated by an intermediate capping layer 180. The intermediate cover layer 180 is made of a transparent material and on at least one of its surfaces with an antireflection coating 185 Mistake. At the in 5 illustrated lighting device extending hole areas 140 between the front and the back of the lighting device through the luminescent layer 120 , the first additional luminescent layer 125 and the second further luminescent layer 126 as well as through the shielding layer 130 ,

The further intermediate substrate 190 is like the intermediate substrate 170 formed as a perforated plate, wherein the hole areas 140 each cavities in the intermediate substrates 170 . 190 correspond. The cavities may be filled with air, another gas or a transparent material. On the inner walls of the cavities in the further intermediate substrate 190 are more shielding walls 136 formed, which extends in extension of the shielding walls 135 extend. The other shielding walls 136 extend such that they are in the plane of the second further luminescent layer 126 between the second further luminescent layer 126 and the adjacent hole area 140 are arranged.

In 5 is from the second further luminescent layer 126 emitted light by double-dashed arrows 26 illustrates while out of the object level 50 reflected or scattered light by dotted arrows 30 is illustrated.

The first and the second further luminescent layer 125 . 126 are made of a transparent material. For example, the first and the second further luminescent layer 125 . 126 each implemented as an OLED luminescent layer.

As in 5 is shown by the second further luminescent layer 126 Light emitted both in the direction of the back of the lighting device and in the direction of the front of the lighting device. The light emitted toward the back of the lighting device becomes on the surfaces of the shielding walls 135 . 136 and on the surface of the shielding layer 130 reflected, so that it is the lighting device ultimately only in the direction of the front of the lighting device can leave.

Due to the multistage nature of 5 illustrated lighting device, the available luminance can be further increased. In addition, by means of the different luminescent layers, ie the luminescent layer 120 and the first and second further luminescent layers 125 . 126 the spectral distribution of the light emitted by the lighting device to be adjusted by the luminescent layers 120 . 125 . 126 be selected with appropriate individual radiation spectra. This can be advantageous for example for professional film recordings in which a color rendering index of more than 90 is required, which can be achieved efficiently by using several OLED luminous layers with individual emission spectra. In addition, the individual luminescent layers 120 . 125 . 126 applied on different substrates, whereby they can be controlled separately with little effort. This in turn, for example, the color rendering index can be set specifically or aging processes of the individual luminescent layers 120 . 125 . 126 can be compensated.

It is understood that the basis of 5 illustrated multi-stage of the lighting device is expandable to any number of stages. In this connection, it is advantageous to achieve the best possible antireflection of Zwischenabdeckplatten used between the individual stages (corresponding to the Zwischenabdeckplatte 180 ). For example, the Zwischenabdeckplatten can be provided on both sides with an antireflection coating.

6 schematically shows a plan view of a section of the lighting devices of 4 and 5 used intermediate substrates 170 . 190 , As already mentioned, the intermediate substrates are 170 . 190 made of a transparent material, which in 6 represented by a hatched area. In the transparent material are the hole areas 140 designed as cavities. On the inner walls of the cavities are the shielding walls 135 . 136 formed by applying a layer of an untransparent material. One of the luminescent layers 120 . 125 . 126 facing side of the shielding walls 135 . 136 , designated 137, is provided with a reflective or specular surface. One of the hole areas 140 facing side of the shielding walls 135 . 136 , designated 138, is also configured as a specular or reflective surface. Alternatively, the page 138 the shielding walls 135 . 136 Also be designed absorbent, for example, with a blackened surface.

Due to the reflective design of the page 137 the shielding walls 135 . 136 On the one hand prevents light from passing through the shielding in the hole areas 140. At the same time it allows the light, if necessary after repeated reflection on the surface of the shielding walls 135 . 136 or the surface of the shielding layer 130 can be delivered in the direction of the front of the lighting device.

An absorbent design of the page 138 the shielding walls 135 . 136 However, it may be advantageous to attach to the Zwischenabdeckplatte 180 scattered light from being scattered toward the back of the lighting device. In addition, the quality of image capture by the hole areas 140, which may be due to reflection on the sides 138 the shielding walls 135 . 136 could be improved.

7 schematically illustrates another lighting device. The lighting device of 7 is essentially the same as that of 5 and 6 , Elements of the lighting device of 7 which those of 1 - 6 are denoted by the same reference numerals. For the properties of these elements, refer to the corresponding explanations 1 - 6 directed.

In the lighting device of 7 is a protective layer on the front of the lighting device 150 provided, which on its surface with microlenses 160 is provided. As related to 3 can be explained by the microlenses 160 the backscattered in the direction of the back of the lighting device light are further suppressed. In 7 is in the second further luminescent layer 126 generated light, which on the surface of a microlens 160 in the protective layer 150 is reflected to the inside, denoted by 26 '. Through the microlenses 160 is achieved that the backscattered light 26 ' in the area through the shielding walls 135 . 136 trained beam traps is directed. The backscattered light is thereby effectively prevented from passing through the hole areas 140 to get to the back of the lighting device.

The microlenses 160 are related to 3 explains between the hole areas 140 arranged and thus form a lattice-like coherent cylindrical lens structure. The extension of the microlenses 160 at the level of the protective layer 150 is again preferably chosen to be larger than the width of the corresponding regions of the luminescent layers 120 . 125 . 126 ,

The in the basis of 1 - 7 Illuminated layers provided for explained illumination devices can consist of a plurality of electrically isolated subareas, so that a plurality of separately controllable luminous areas result. If these separately controllable lighting areas are supplied with power via a passive or active matrix control, the lighting apparatus can be controlled to generate different areal illumination patterns. The lighting patterns can be used for decorative or functional purposes. For example, text or images can be generated. This can be used, for example, for advertising purposes, to display information or to issue warnings.

At the in of 1 - 7 Illuminators shown are the dimensions of the structures in the various layers, eg cross-section of the hole areas, width of the webs of the luminescent layers, thickness of the various substrates, typically in the range of 1-1000 microns. However, a range of 5-50 μm is preferred. The luminescent layers are typically thinner than 1 μm.

8th shows an example of use related to 1 - 7 explained lighting device.

At the in 8th shown application example is the lighting device in spectacle lenses of a pair of glasses 200 arranged. For example, the lighting device may be applied to an inner or outer surface of the lenses. Alternatively, the lighting device may also be embedded in the lenses. The glasses 200 can be designed as reading glasses, data glasses or surgical loupe. Consequently, the spectacle lenses can also be provided with suitable optical imaging properties. For example, the glasses 200 be designed for viewing objects in the vicinity. The of the glasses 200 emitted illumination radiation 20 Illuminates an object 250 For example, the pages of a book or a surgical field.

For supplying power to the illumination devices in the spectacle lenses of the spectacles 200 is an energy source 220 provided, for example, a rechargeable battery or a battery. At the in 8th The application example shown is the energy source 220 over a cable with the glasses 200 connected. Alternatively, the energy source 220 also in the glasses 200 be integrated.

At the in 8th shown application example, there are advantages in that the integrated in the lenses lighting device is very compact and lightweight, since it consists essentially of a coating of the lenses, said coating has a thickness of typically a maximum of a few tenths of a millimeter. The already existing eyeglass lenses are thus used as a carrier substrate for the lighting device. The spectacle lenses may be specifically adapted and provided with an optical effect or not.

At the glasses 200 Lighting is always automatically located where it is needed. The illumination radiation 20 is created directly between the eye and the observed object. The illumination distribution can be further optimized by adjusting according to the in 3 and 7 arrangements shown are used microlenses, which are designed asymmetrically, so that the illumination radiation 20 receives a preferred direction for the area of the typical field of view.

For special applications, the illumination devices integrated in the lenses may also be designed to emit light in the ultraviolet spectral range, either in addition to light in the visible spectral range or exclusively. In this way it is possible to observe fluorescent objects. For this case, the spectacle lenses may also be provided with an additional spectral coating on the side facing the eye, which blocks ultraviolet radiation but allows visible radiation to pass. Applications for ultraviolet spectral irradiance illuminators include, for example, in bloodstain forensics research, in the study of fluorescent security features, e.g. in bills, or in geology.

9 schematically illustrates another application example of in 1 - 7 illustrated lighting device.

In 9 is the lighting device 100 Part of a camera lens 300 for a camera. The camera lens 300 includes a front lens 310 and optionally another look 320 with one or more lenses or other imaging elements. The camera can be a movie camera, a video camera, or a still camera. The camera can be configured analog or digital.

The lighting device 100 is in front of the front lens 310 of the camera lens 300 arranged. In this case, the lighting device 100 be implemented using planar substrates.

Starting from the lighting device 100 is the illumination radiation, illustrated by solid arrows 20 , in the object plane 50 issued. Starting from the object plane 50 becomes scattered or reflected light, illustrated by a dashed arrow 30 , through the lighting device 100 in the camera lens 300 added. Through the front lens 310 and the optional further optics 320 an image of the detected scattered or reflected radiation takes place 30 on an image pickup device, eg, a photosensitive film or a photosensitive chip.

10 schematically illustrates another embodiment of the in 1 - 7 described lighting device.

At the in 10 illustrated application example is the lighting device 100 as part of an imaging optics 400 intended. The imaging optics 400 includes a front lens 410 and optionally another optic, which may consist of one or more other lenses or other imaging elements. The lighting device 100 is on the surface of the front lens 410 the imaging optics 400 applied. Through the front lens 410 and the more optics is from the imaging optics 400 detected light on a detector 450 displayed. The detector may, for example, be a camera. However, visual observation by the human eye is also possible. Optionally, a spectral filter 420 in the beam path between the front lens 410 and the detector 450, for example, between the front lens 410 and the further optics 430.

At the in 10 Application example is the illumination radiation generated by the illumination device 100, shown schematically by solid arrows 20 , in the direction of the object plane 50 issued. Starting from the object plane 50 is reflected or scattered light, schematically represented by a dashed arrow 30 , through the front lens 410 and the lighting device applied thereto 100 in the imaging optics 400 taken and over the front lens 410 and the further optics 430 on the detector 450 displayed.

In the imaging optics 400 For example, it could be a still or motion picture camera. Because of the right on the front lens 410 applied lighting device 100 For example, a space-saving alternative to a lighting ring formed around a lens or to a separate illumination source is provided. With sufficiently small structuring of the lighting device 100 For example, impairments of the image quality due to the structures introduced into the beam path in the illumination device can be avoided since the illumination device is sufficiently far away from the object plane to be sharply imaged 50 is removed.

Alternatively, however, the lighting device 100 , similar to that of 9 explained application example, are mounted reversibly as Vorschraubkomponente on a lens. In this case, the illumination device can be applied to a substrate which is planar or has a curvature that deviates from the front lens 410. For example, the lighting device 100 be applied to a substrate which is concave, whereby an increase in illuminance in the center of the image can be achieved.

The spectral filter 420 can be used to unwanted spectral ranges from the on the imaging optics 400 filter out detected light. This may be, in particular, radiation in the ultraviolet spectral range which is emitted by the illumination device 100 is generated, for example, to cause a fluorescence excitation in an examined object. The spectral filter 420 may be a separate component of the imaging optics 400 be, which may optionally be designed interchangeable. Alternatively, the spectral filter 420 be applied to a lens or other optical element.

At the in 10 The arrangement shown can also be part of an endoscope with wide-field detection. Compared to a conventional illumination by means of a separate optical fiber or by means of a beam splitter again results here the advantage of a small footprint, which is of great importance in endoscopes.

At the in 10 However, it can also be a part of a microscope, for example a stereomicroscope, a surgical microscope, a compound or wide field microscope or an ophthalmological microscope. Furthermore, it may be part of an industrial measuring device. The advantage over conventional lighting devices, in turn, is that little space is required and even with a small working distance in relation to the diameter of a lens used efficient lighting can be achieved.

When using the lighting device 100 in a microscopic arrangement, it should be noted that the structured illumination device is not directly in the object plane 50 or a conjugate image plane may lie. This applies to lenses, zoom systems, reflected-light and transmitted light illumination arrangements. The lighting device 100 but in one Pupillenebene the imaging optics are used, for example, in the plane of a microscope aperture or in an accessible lens pupil. Various different areal illumination patterns, eg rings, segments, half-pupils, etc., can be used to generate different microscopic contrasting methods and to continuously mix them by a dimming process, for example with a bright field image or a dark field image. This results in advantages over a hard switching between different microscopic contrast methods. With a division of the planar illumination in half-pupils, a continuous connection of the spatial image contrast is possible.

A concrete example of application for the lighting device 100 in a microscope is in 11 illustrated.

11 shows an example of a stereomicroscope 500 in which the basis of 1 - 7 explained lighting device is arranged in front of the imaging optics. Starting from the lighting device 100 becomes light on an object to be observed 550 issued. From the observed object 550 reflected or scattered light is transmitted through the lighting device 100 in the microscope 500 in an object of the microscope 500 recorded and an observation section 510 of the microscope 500 fed. In the observation section 510 For example, there may be eyepieces which are a visual observation of the observation object 550 through the human eye. Alternatively or additionally, the observation section 510 also be provided with a camera.

In addition to the application examples already mentioned, the basis of 1 - 7 described lighting device can also be used in conjunction with matrix-like arrangements of miniature lenses. By the matrix-like arrangement of mini-lenses, for example, a 1: 1 image can be made on a camera chip. In such arrangements, which can be produced by means of a plurality of superimposed microlens arrays, a very large ratio of viewing area to working distance can be achieved. The diameter of the miniature lenses is typically less than 5mm. The basis of 1 - 7 described illumination device can be introduced in this case to realize a reflected light illumination between the camera chip and the object plane.

In addition, the basis of 1 - 7 described lighting device can also be used for reflection-free illumination of images. For this purpose, a transparent protective material arranged in front of the image, for example a protective glass, can be replaced by a lighting device which covers substantially the entire surface of the image with the aid of 1 - 7 explained properties are provided. In this way, the image is illuminated very evenly and reflections from separate light sources on the transparent protective material are avoided. Since the use of OLED luminous layers allows the illumination radiation emitted by the illumination device to be adjusted in terms of its spectral range such that it contains no components in the ultraviolet spectral range, the illumination device can also be used for objects sensitive to ultraviolet radiation, eg paintings, photographs or the like become. By varying the spectral distribution of the emitted illumination radiation by an electrical control of the luminescent layer or the luminescent layers, the illumination can also be adapted effectively to the respective object to be illuminated and / or the environmental conditions. Furthermore, the brightness of the lighting is easily controllable. In combination with a brightness sensor, an automatic brightness control can take place.

Another application of the basis of 1 - 7 described lighting device is as part of a watch glass, for example, clock face lighting.

In addition, the lighting device can also be used in showcases or cabinet doors as a light source. There are similar advantages to lighting images. In addition, use in glazed doors of refrigerators or freezers, e.g. in food markets, possible. In this case, it proves to be an advantage over conventional types of illumination that OLED-based luminescent layers can produce light with high efficiency and low heat generation.

Furthermore, it is possible to use the 1 - 7 explained lighting device for lighting and possibly monitoring of adjacent rooms by using windows. Here, an advantage results from the fact that a large-area illumination is realized, which causes no glare and illuminates an object to be observed or people to be observed exactly from the direction from which the observation is made. In the event that the observer or a camera used for observation purposes should not be visible, such as when monitoring in supermarkets or in interrogation rooms, the lighting device may be provided on the side facing the observer additionally with a semitransparent mirror layer.

Another application of the basis of 1 - 7 explained lighting device can be found in optical copiers and scanners. Here it is currently customary to draw a line-shaped light source over the object to illuminate an object, for example a sheet of paper. The associated mechanical complexity can be achieved by using the basis of 1 - 7 explained planar lighting device can be avoided by a substantially full-surface illumination of the object is realized. The image recording can then take place through the illumination device. A further advantage is that the image acquisition can take place with a two-dimensionally configured camera, which in turn allows a higher copy or scan speed to be achieved. In this application example, the mean distance between the hole areas in the lighting device should preferably be less than 50 μm.

Another field of application concerns so-called teleprompters, with which lecturers can read their text without the text being able to be seen by the audience. Such teleprompters are used at e.g. Live events or used in television. Currently, teleprompters usually consist of a projector and a partially reflecting plate. The speaker sees the reflected, projected text while the viewer sees only the partially reflecting plate.

With the help of the basis of 1 - 7 explained lighting device, the projector can be saved, since the text can be displayed directly with the lighting device according to the invention. For this purpose, the lighting device is to be designed so that it acts with a sufficient resolution as a text and / or bildbildstellendes display. As has been explained above, only partial areas of the lighting device have to be separately electronically controllable for this purpose. For this purpose, the usual in displays passive matrix method or active matrix method can be used.

Furthermore, the basis of 1 - 7 explained lighting device can also be used in reflective display devices, for example in LCoS display devices (LCoS: "Liquid Crystal on Silicon", liquid crystal on silicon). Here, the lighting device can be arranged at a short distance in front of the reflective display device and a very flat construction is made possible. In this case, the reflective display devices can also be used for large-area display, since a complex incident illumination with beam-forming elements is not required. In this application example, the mean distance between the hole areas in the lighting device should be smaller than the pixels of the display device.

It is understood that the above-described implementations of the lighting device and application examples can be suitably combined with each other.

Claims (24)

Lighting device comprising: a luminescent layer (120), a shielding layer (130) of a nontransparent material disposed between a backside of the lighting device and the luminescent layer (120), and a plurality of transparent hole areas (140) where the luminescent layer (120) and the shielding layer (130) are broken through and which extend between the back and a front of the lighting device, wherein the shielding layer (130) has respective edge regions (132) formed around the hole regions (140) which project beyond the luminescent layer (120) and prevent radiation of light towards the backside of the illumination device, such that light is unidirectional toward the front of the illumination device is emitted, wherein the hole areas (140) are irregularly arranged in the plane of the shielding layer (130). Lighting device after Claim 1 , wherein the edge regions (132) protrude by at least 1 micron above the luminescent layer (120). Lighting device after Claim 1 or 2 comprising: shielding walls (135, 136) formed of non-transparent material around the hole areas (140), the shield walls (135, 136) extending along a portion of the hole areas (140) between the shielding layer (130) and the front of the lighting device , Lighting device after Claim 3 wherein the shielding walls (135) are connected to the shielding layer (130). Lighting device after Claim 3 or 4 , wherein the shielding walls (135) extend between the luminescent layer (120) and the hole areas (140). Lighting device according to one of Claims 3 - 5 comprising: at least one further luminescent layer (125, 126) of a transparent material arranged between the luminescent layer (120) and the front of the lightening device, the hole regions (140) extending through the further luminescent layer (125, 126), and wherein the shielding walls (135, 136) extend between the further luminescent layer (125, 126) and the hole areas. Lighting device after Claim 6 , wherein the further luminescent layer (125, 126) is designed as an OLED luminescent layer. Lighting device after Claim 6 or 7 comprising: an antireflective layer (155, 185) disposed between the further luminous layer (125, 126) and the front side of the lighting device. Lighting device according to one of Claims 5 - 8th wherein the shielding layer (130) and / or the shielding walls (135, 136) are designed to be reflective. Lighting device according to one of Claims 6 - 9 comprising: a transparent intermediate substrate (170, 190) on the surface of which the further luminescent layer (125, 126) is applied. Lighting device according to one of the preceding claims, comprising: a transparent protective layer (150) which is arranged on the front side of the lighting device. Lighting device after Claim 11 wherein the protective layer (150) comprises an antireflective layer (155). Lighting device after Claim 11 or 12 comprising: a plurality of microlenses (160) disposed on the front of the lighting device. Lighting device after Claim 13 wherein the microlenses (160) are disposed between the hole regions (140). A lighting device according to any one of the preceding claims, comprising: a transparent back substrate (110) disposed between the shielding layer (130) and the back side of the lighting device. A lighting device according to any one of the preceding claims, comprising: an antireflective layer (115) on the back side of the lighting device. Lighting device according to one of the preceding claims, wherein the hole regions (140) in the plane of the shielding layer (130) in at least one direction have an extension of 500 microns or less. Lighting device according to one of the preceding claims, wherein the lighting device (100) comprises a planar or a curved support substrate (110). Lighting device according to one of the preceding claims, wherein in the plane of the luminescent layer (120) a plurality of luminous regions are provided, which are separately controllable. Lighting device according to one of the preceding claims, wherein the hole regions (140) extend substantially perpendicular to the luminescent layer (120) and the shielding layer (130). Optical device with a lighting device (100) according to one of the preceding claims. Optical device according to Claim 21 wherein the illumination device (100) is applied to an optical element of the optical device. Optical device according to Claim 22 wherein the optical element is a transmissive imaging element, a reflective imaging element or a beam splitter element. Optical device according to one of Claims 21 - 23 wherein the optical device is an endoscope, a microscope, a magnifying glass, a pair of glasses, a lens, a camera, a display device, a copier or a scanner.

Images