EP2238487A2

EP2238487A2 - Light guide device, illumination device with a light guide device of said kind and method for the production of a light guide device of said kind

Info

Publication number: EP2238487A2
Application number: EP08842992A
Authority: EP
Inventors: Georg Diamantidis; Fred Tonhofer
Original assignee: NOCTRON SOPARFI SA
Current assignee: NOCTRON SOPARFI SA
Priority date: 2007-10-18
Filing date: 2008-10-16
Publication date: 2010-10-13
Also published as: DE102007050271A1; CN101896843A; WO2009052992A3; DE102007050271B4; WO2009052992A2

Abstract

The invention relates to a light guide device (10; 70, 72, 74, 76, 78, 80) having a light guide element (12), which is delimited by a first main surface (14) and a second main surface (22) that is spaced parallel to the first main surface, and having a reflection device (24), which is arranged on the side of the second main surface (22) of the light guide element (12) and with which light can be reflected in at least the direction of the inside of the light guide element (12). The reflection device (24) comprises material islands (26) made of a preferably transparent reflective material. The invention further relates to an illumination device (42; 100) comprising a light guide device (10; 70, 72, 74, 76, 78, 80) of said kind and to a method for the production of the light guide device (10; 70, 72, 74, 76, 78, 80).

Description

Light guide device, moistening device with such a light guide device and method for producing such a light guide device

The invention relates to a light guide device according to the preamble of claim 1, a lighting device according to the preamble of claim 22 and a method according to the preamble of claim 25.

Light conductor means of the type mentioned v _/ ground, for example, used in lighting devices to be flat construction as possible for technical and / or aesthetic reasons, being generated by such illumination devices useful light to be delivered mainly via the first main surface of the light guide member of the light guide.

Input optical waveguide devices are used, for example, in the backlighting of liquid crystal panels in liquid crystal displays, which are generally known as LCD screens. LCD screens are particularly popular because of their flat design.

Such LCD screens comprise a liquid crystal panel, which is illuminated by means of a lighting device of the type mentioned. Frequently, the illuminants used require additional components, such as a hole reflector, a Fresnel lens and usually a plurality of diffusion filters, which are arranged between the liquid crystal panel and the lighting means.

However, this design often makes the contrast and brightness of the visible side of the LCD screen

BESTAETINGUNGSKOPIE recognizable image adversely affected. The diffusion filters attenuate the intensity of the radiation emitted by the illumination device by about 10% before reaching the liquid crystal panel. The shadow mask has an even stronger effect. Through them, about 25% to 30% of the radiation emitted by the illumination device is absorbed, which is why only a correspondingly smaller proportion of light reaches the liquid crystal panel to be illuminated. In addition, it comes through the shadow mask to adverse interference effects.

To compensate for these interference effects and to improve the achievable contrast of recognizable on the visible side of the LCD screen image, the Fresnel lens is provided. However, this also causes the angle at which the screen can be viewed to be reduced, so that an image produced by it is still clearly visible.

There is therefore a desire for a light guide device and a lighting device in which with regard to the backlighting of LCD screens can largely be dispensed with above-mentioned correction components and which is still suitable as background lighting in a Flussigkristall screen, has a good luminosity and also flat builds.

The flat-building properties are also increasingly in lighting devices in the form of lamps for lighting rooms or outdoor areas in demand because the flat design an attractive appearance can be achieved. Known low-profile lighting devices have a passive light-emitting body and a primary light source.

Passive illuminants have light-conducting properties, con However, without additional active primary light source emit no light. Regardless of a flat design, it is desirable for passive filaments to emit the useful light without major intensity losses relative to the light emitted by the light source.

Often, however, a desired flat construction can not be reconciled with the required luminance of the lighting device.

Even in lighting devices in which a primary light source is provided, whose light is coupled into a plurality of passive luminous bodies, which in turn emit the useful light, it is often desirable that the passive luminous bodies are flat. In addition, passive luminous bodies in such lighting devices should be able to emit useful light in the desired intensity over a considerable surface area, so that even large rooms and / or extensive outdoor areas can be illuminated with a single active primary light source.

It is therefore desirable optical fiber devices that are able to forward light coupled in to them over long distances, on the one hand, and deliver useful light with high light output on the other hand.

By the reflection device, the light output of the optical fiber device is increased by, for example, via the second main surface of the light guide element emitted light is also reflected in the light guide element and can leave this as useful light on the first main surface.

In known light-conducting devices, the reflection device is, for example, in the form of a reflection foil formed, which is applied flat on the second main surface of the light guide element.

The length of the route, over which light can be conducted and after which useful light can be emitted by the light guide device with sufficient intensity, depends on the structure of the light guide element. The intensity of the useful light generally decreases relatively sharply with increasing distance from the light source.

Taking into account the above idea, it is therefore an object of the invention to provide a light guide device of the type mentioned, whose light-guiding properties are improved and which useful light gives off with good efficiency.

This object is achieved by a light guide device having the features specified in claim 1.

By providing islands of material from a reflective material, good homogenization of the light and good luminosity can be achieved. In addition, the light-guiding properties of the optical waveguide device are improved since light can be transmitted by reflection without excessive intensity losses from one material island to the next island of material along the second main surface of the optical waveguide element. However, part of the light is always reflected in the direction of the interior of the light guide element, which results in a more homogeneous distribution of intensity within the light guide element.

The term "islands of material" is to be understood as meaning regions of reflective material which are not directly connected to corresponding adjacent islands of reflective material. The islands of material may be arranged in an uneven distribution to counteract negative optical effects associated with periodic structures.

However, it may be advantageous if the material islands are arranged as specified in claim 2.

It has proved to be particularly favorable when the reflection material according to one of claims 3 to 5 is selected.

It is advantageous if the reflection particles, as indicated in claim 6, are distributed in a carrier material, which in turn may be selected according to one of claims 7 or 8.

Good reflection efficiency can be achieved if the islands of material are arranged as stated in claim 9. A further advantageous increase of the reflection and

The light guiding effect of the optical waveguide device can be achieved by the measure according to claim 10.

Production technology, the training may be advantageous according to claim 11.

If the optical waveguide device is designed as indicated in claim 12, decor or information patterns can be formed and rendered recognizable to an observer. These can be either black and white or colored. Such a light guide device can be used for example in signs or decorative lights.

When the reflector substrate is provided as specified in claim 13, reflections remain between the islands of material. xionsmaterial, the second main surface of the light guide element and the reflector substrate a Lichtleit channel system forming gaps exist, which can be passed over the material islands reflected light also over greater distances along the second major surface of the light guide element. In this case, a distance between the reflector substrate and the light guide element is favorable, as indicated in claim 14.

An improved reflection effect is achieved by the measure according to claim 15. For the paper sheet according to claim 15 basis weights have been found to be favorable, as indicated in claim 16.

By the measures according to claim 17, the efficiency of the optical fiber device can be further increased.

The material islands may have different outer contours in plan view in the direction of the second main surface of the light guide element and in particular in claim 18.

A good efficiency of the optical waveguide device can be achieved if the material islands have a radial extension in a direction towards the second main surface of the optical waveguide element, as indicated in claim 19.

A uniform over the extent of the light guide element efficiency of the optical fiber device could be achieved at distances between two islands of material, which correspond to the distances specified in claim 20.

In conjunction with the material islands made of reflective material, in particular light guide elements made of materials mentioned in claim 21 have proved to be favorable. The object of the invention is also to provide a lighting device of the type mentioned, the luminous efficacy is improved.

This is achieved in a lighting device having the features specified in claim 22. Due to the high efficiency of the light guide device, light generated by the light sources can be effectively converted into useful light. Such a lighting device can be used for backlighting the liquid crystal panel of an LCD screen or as a stand-alone light source for lighting rooms or outdoor areas.

In this case, it has proved to be particularly advantageous if the light emitted by the light sources is fed into the optical waveguide device in the manner indicated in claim 23.

By the measure according to claim 24, a lighting device can be created, the primary light source can be effectively used for the illumination of remote indoor or outdoor areas.

Moreover, it is an object of the invention to provide a method by which a light guide device explained above can be manufactured in a favorable manner.

This object is achieved by a method according to claim 25. Because the material islands are first applied to the substrate and the light guide element is subsequently coated therewith, a substrate already provided with material islands can be temporarily stored and only appropriately cut and used as needed. If the substrate is designed as specified in claim 26, it is particularly flexible and therefore easy to handle.

In practice, an adhesive according to claim 27 has been proven.

The possibility of producing signs or decorative lights opens up by the measure according to claim 28. A possible image is given by the arrangement of the islands of material on a light substrate or a bright material according to claim 29. However, greater variety can be achieved if the imprint itself reproduces an image in black and white or in color, as indicated in claim 30.

In lighting devices with a light guide device decor or information pattern can be generated by a suitable combination of imprint and islands of material. Depending on whether or not the illuminants are in operation, different images may be visible to the observer since only the islands of material illuminate with active illuminants. However, areas without islands of material appear dark to the viewer compared to the glowing islands of material. In daylight, the print is perceived as a normal printed film. As a result, the room for maneuver is very high.

A favorable way of applying the islands of material to the substrate is mentioned in claim 31.

It has proved to be advantageous if the substrate according to claim 32 is applied to the light guide element.

Hereinafter, embodiments of the invention are based on explained in more detail in the drawings. In these show:

FIG. 1 shows a section through an optical waveguide device with material islands made of a reflection material;

FIG. 2 shows a section through the optical waveguide device according to FIG. 1 along the section line II - II there, wherein the material islands have a circular outer contour;

FIG. 3 shows a section, corresponding to FIG. 2, of a modified optical waveguide device, in which the material islands have a square outer contour;

FIG. 4 shows a section, corresponding to FIG. 2, of a further modified optical waveguide device, in which the material islands again have a circular outer contour but a larger radial extent and a greater distance from each other than in FIG. 2;

FIG. 5 shows a section, corresponding to FIG. 2, of a further modified optical waveguide device, in which pairs of material islands have opposite semi-circular outer contours;

FIG. 6 shows a section, corresponding to FIG. 2, of a further modified optical waveguide device, in which the material islands are designed like ribs;

7 shows a section corresponding to FIG. 2 of a further modified optical waveguide device, in which the material islands have a rectangular outer have contour;

FIG. 8 shows a section, corresponding to FIG. 2, of a further modified optical waveguide device, in which the material islands have an oval outer contour which corresponds to the outer contour of two mutually spaced semicircles, which are connected by straight lines;

FIG. 9 shows a section through an illumination unit, which encompasses the optical waveguide device according to FIG. 1, and through a liquid crystal panel attached to the illumination unit;

FIG. 10 shows a lighting device with a plurality of optical waveguide devices;

11 shows a section through an information label, which comprises a light guide device according to FIG. 1, in which a printed reflector substrate is used.

FIGS. 1 and 2 show an optical waveguide device 10 which comprises, as a light guide element, a planar and substantially homogeneous light guide plate 12 made of transparent, optical quality acrylic glass. Also, fiber optic elements 12 with other than planar geometries can be used. The light guide plate 12 may also be made of another homogeneous translucent material, such as a glass or an epoxy resin. The light guide plate 12 is preferably clear and free of streaks and bubbles.

The light guide plate 12 has a first main surface 14, over which, for example, two opposite each other Overlying narrow surfaces 16, 18 coupled light is emitted as useful light. The coupling of light over the narrow surfaces 16, 18 in the light guide plate 12 is indicated in Figure 1 by the wavy arrows 20. A second main surface 22 of the light guide plate 12 extends parallel spaced to its first main surface 14th

On the side of the second main surface 22 of the light guide plate 12, the light guide device 10 comprises a reflection device 24. This serves to homogeneously distribute light which leaves the light guide plate via its second main surface along the second main surface 22 of the light guide element 12 and also proportionally into Direction to the inside of the light guide plate 12 to reflect the yield of the light guide plate 12 via the first

Main surface 14 leaving the useful light of the light guide device 10 to increase.

The reflection device 24 comprises material islands 26 made of a highly reflective reflection material, which contact the second main surface 22 of the light guide plate 12 and which are arranged substantially regularly. The latter can be seen in FIG. It is also possible to dispense with a periodic arrangement of the material islands 26.

The reflective material of the material islands 26 is preferably translucent or transparent. Optionally, the reflective material with the reflective particles and pigments are added, as they are used in tinted glasses, acrylic or other plastics.

In FIGS. 1 and 2, only one material island 26 is provided with a reference character. Between the material islands 26 remain areas which are free of reflection material. As can be seen in FIG. 2, the material islands 26 have a circular outer contour in a plan view in the direction of the second main surface 22 of the light guide plate 12.

On their side remote from the second main surface 22 of the light guide plate 12, the material islands 26 contact a reflector substrate in the form of a white paper sheet 28. This is held by the material islands 26 at a distance from the second main surface 22 of the light guide plate 12, so that it does not touch. In this way, between the light guide plate 12 facing outer surface 30 of the paper sheet 28, the second main surface 22 of the light guide plate 12 and the material islands 26, a Lichtleit- channel system 32 is formed, which will be discussed in more detail below.

The distance between the white paper sheet 28 and the second major surface 22 of the light guide plate 12 and thus the thickness of the material islands 26 are about 1 micron to about

1 mm, preferably about 5 microns to about 100 microns, more preferably about 8 microns to about 20 microns and more preferably about 14 microns.

The white paper sheet 28 has a basis weight of from 50 g / m ² to 200 g / m ² , preferably from 80 g / m ² to 170 g / m ² , more preferably from 100 g / m ² to 150 g / m ^2, and more preferably of 120 g / m ² .

The paper sheet 28 may be obtained from both a cellulosic fiber and a synthetic fiber based paper.

As a reflector substrate 28, for example, instead of the white paper sheet, a white plastic film may also be used. preferably made of PET, PVC or polystyrene, or a mirror film may be provided.

On the remote from the light guide plate 12 surface 34 of the white paper sheet 28 is applied to a reflective layer 36, for example in the form of a self-adhesive mirror film or a reflective layer of metal, especially aluminum, which was applied directly, usually by vapor deposition, to the reflector substrate 28. This sandwich arrangement comprising the reflection layer 36, the white paper sheet 28 and the material islands 26 covered by the reflection device 24 is covered by a housing 38 of the reflection device 24, the bottom surface 40 of which rests against the reflection layer 36. In particular, if the optical waveguide device 10 is not exposed to mechanical stress, the housing 38 can also be dispensed with in a modification.

The reflection material from which the material islands 26 are formed comprises reflection particles of scandium oxide. Alternatively, oxides of lanthanum and the rare earth metals such as cerium oxide, preseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, yttrium oxide or lutetium oxide can serve as the material for the reflection particles. Preferably, only reflection particles of pure scandium oxide or pure ytterbium oxide are provided.

The reflection on the reflection particles can take place on diffuse surfaces or on reflecting surfaces. Ideally, individual separate reflection particles form the material islands 26. In the exemplary embodiments shown here, the reflection particles are in turn distributed homogeneously in a carrier material, for which in particular a Epoxy resin or a polyester resin in question.

In the manufacture of the optical waveguide device 10, for example, a pattern is printed on the second main surface 22 of the optical waveguide plate 12 using a reflection color, e.g. by screen printing. In addition to a liquid resin binder containing a hardener, the reflection paint comprises the reflection particles of scandium oxide or other compounds mentioned above in a finely homogeneous distribution. Before the resin cures to the substrate, the paper sheet 28 can be placed on the resin / hardener / reflective particle mixture and pressed, which is then fixed by the material islands 26 obtained after curing of the resin, whereby the above-mentioned distance to the light guide plate 12 is obtained ,

Alternatively, initially a corresponding pattern can also be printed on the reflector substrate 28, in particular the white paper sheet 28. For this purpose, the reflection ink used is a screen-printable adhesive which is known per se, for example a liquid resin binder containing a hardener, to which previously reflection particles of, in particular, scandium oxide have been admixed. This adhesive, which is provided with reflection particles, is printed on a corresponding reflector substrate, for example a paper, in a corresponding printing machine, which can be present, for example, in a width of 20 cm to 2.5 m. After the corresponding pattern has been cured on the paper, for example by means of UV light or heat, the remaining islands of material 26 can be covered with a silicone film and the paper thus printed can be wound onto a roll with the silicone film and thus stored. With sheets of such printed paper can then be coated by means of a cylinder printing unit, for example, acrylic plates, which serve as an optical fiber element 12. This results in a laminate structure of paper sheet 28 and light guide element 12, in which the above-mentioned distance between the paper sheet 28 and the second main surface 22 of the light guide element 12 remains.

Alternatively, a silicone material, in particular an elastic silicone compound, which can be obtained by adding a hardener to a less viscous silicone oil can serve as a binder for the reflection color. Correspondingly, such a silicone oil provided with a hardener, in which the reflection particles are homogeneously distributed, can be printed on either the second main surface 22 of the light guide plate 12 or the white paper sheet 28, so that it becomes elastic after hardening of the less viscous silicone oil Silicone compound corresponding material islands 26 form.

The reflective particles have a diameter of about 0.5 μm to about 300 μm, preferably from about 0.5 μm to about 50 μm, more preferably from about 0.5 μm to about 4, depending on the volume provided by the material islands 26 μm and more preferably about 2 μm.

The reflection particles are largely immobile within the binder. With an elastic binder, however, they may deform with the binder.

Depending on the concentration of the reflective particles within the carrier material the material islands 26 modification can in egg ner here not shown specifically also be dispensed with the white ^¬ SSE paper sheet 28, and only the Refle ^¬ xionsschicht 36 used as a reflector substrate. In this case, the reflection layer 36 abuts the material islands 26 accordingly. FIGS. 3 to 8 show sections of various modifications of the optical waveguide device 10 corresponding to FIG. 2, wherein the material islands 26 each have different outer contours and distances from each other in plan view in the direction of the second main surface 22 of the optical waveguide element 12. Correspondingly, the outer contour of the material islands 26 may correspond, for example, to that of a circle (FIGS. 2 and 4), a semicircle (FIG. 5), a square (FIG. 3) or a rectangle (FIGS. 6 and 7). In Figure 8, material islands 26 are shown, the outer contour of the clear outer contour of two spaced-apart semicircles corresponds, the straight sides facing each other. In the embodiment of Figure 6, the islands of material 26 are formed rib-like. The outer contour of other polygons is also considered.

In the exemplary embodiment according to FIG. 4, the areal coverage of the material islands 26 on the second main surface 22 of the light guide plate 12 in the direction of the narrow surfaces 16, 18 decreases inwards. That is, the distances between the islands of material 26 become larger with increasing distance from the narrow surfaces 16, 18 in this direction. Thus, in the outer edge region of the second main surface 22 of the light guide plate 12 proportionally more light from material islands 26 is reflected as in the more inner area, thus a possible loss of intensity of the light depending on the distance from the narrow sides 16, 18 of the light guide plate 12 is taken into account.

If the material islands 26 have the outer contour of a semicircle, as shown in Figure 5, these may be arranged in pairs so that the straight outer edges of two material islands 26 are opposed.

The islands of material 26 have in supervision in the direction of second main surface 22 of the light guide element 12 seen, so in the plane of the islands of material, a radial extent of about 0.01 mm to about 100.0 mm, preferably from about 0.05 mm to about 10.0 mm, more preferably from about 0th , 1 mm to about 5.0 mm, and more preferably from about 0.2 mm to 1.0 mm. If material islands 26 have an irregular outer contour, the mean clear outer contour of the corresponding material islands 26 can be used as a reference variable for their radial extent.

The distance between two islands of material 26 is about 0.01 mm to about 100.0 mm, preferably about 0.05 mm to about 10.0 mm, more preferably about 0.1 mm to about 3.0 mm and particularly preferably about 0 , 2 mm to 1.0 mm.

A good light reflection and light-guiding effect of the optical waveguide device 10 is present in particular when the ratio of the radial extent of the material islands 26 to their distance from one another is approximately 1: 4 to approximately 5: 1. In this case, not less than 0.5 g of reflection particles, preferably scandium oxide 99.9% of white powder, should be distributed in a volume of 1 liter of the carrier material. Preferably in a volume of 1 liter of the carrier material about 0.5 g to 25 g, more preferably about 1 g to about 10 g and more preferably about 1 g to about 2.5 g

Reflective particles, preferably scandium oxide 99.9% white powder, distributed.

With regard to the optical waveguide devices 10 shown in FIGS. 3 to 8, by the way, the statements made with respect to the optical waveguide device 10 shown in FIGS. 1 and 2 also apply mutatis mutandis.

As already mentioned above, between the second main surface 22 of the light guide plate 12, which is assigned to this outside surface 30 of the white paper sheet 28 and the material islands 26 formed the light guide channel system 32. Light which leaves the light guide plate 12 via its second main surface 22 in the direction of the material islands 26 is partially reflected by the reflection particles present in the material islands 26 in many spatial directions with a directional component parallel to the second main surface 22 of the light guide plate 12.

Depending on the angle of incidence of the light rays on the second main surface 22 of the light guide element, a part of the light can be reflected again in the direction of the white paper sheet 28. Accordingly, light from the white paper sheet 28 can be reflected toward the light guide plate 12, with wide reflection at the surface 30 of the white paper sheet. In this way, a portion of the light within the channel system 32 is forwarded. In this case, light is reflected in part by material islands 26 or the reflection particles distributed therein and thus passed on from a material island 26 through the channel system 32 to the next material island 26.

The reflection particles made of scandium oxide or another suitable compound cause reflections in a homogeneous manner over the extent of the second main surface 22 of the light guide plate 12 or of the material islands 26, in which light is deflected at an angle such that a part thereof strikes upon impact on the second main surface 22 of the light guide plate 12 enters into this and leaves it on the first main surface 14 as useful light again.

Via the channel system 32, therefore, light coupled into the light guide plate 12 is distributed uniformly over the extent of the light guide plate 12, which emits so homogeneous useful light. This ability of the optical fiber device 10 to effectively produce a homogeneous useful light can be used, for example, in lighting devices.

An example of such a lighting device in the form of a lighting unit 42 is shown in FIG. 9 in connection with the illumination of a liquid crystal panel 44.

The lighting unit 42 comprises the light guide device 10 as a secondary light-coupled passive lighting body and a respective housing 46 or 48 with U-shaped cross-section and not specifically provided with a reference end walls, which are supported on the opposite narrow surfaces 16, 18 of the light guide plate 12. The respective open side of the housing 46 or 48 points in the direction of the correspondingly adjacent narrow surface 16 or 18 of the light guide plate 12.

The housings 46 and 48 will be explained below only by the example of the housing 46 to be recognized in FIG. The statements on this apply mutatis mutandis to the case 48 shown in Figure 9 below.

The housing 46 defines, with the narrow surface 16 of the light guide plate 12, an interior space 50 in which light sources are arranged as a primary light source in the form of a plurality of semiconductor light chips 52.

The semiconductor light-emitting chip 52 comprises, for example, an n-type layer of n-GaN or n-type InGaN and a p-type layer of a III-V semiconductor material such as p-type GaN. Between such an n-type and such a p-type layer, an MQW layer may be disposed. MQW is the abbreviation for "Multiple Quantum Well". An MQW material contains an interlayer which has an electronic band structure modified according to the sub-lattice structure and emits corresponding light at other wavelengths. By choosing the MQW layer, the spectrum of the radiation emitted by the pn-semiconductor luminescent chip can be selectively influenced.

Instead of the semiconductor luminescent chips 52, other light sources, such as fluorescent tubes may be provided. Such fluorescent tubes can be designed as compact fluorescent lamps, which are also known under the term energy-saving lamps or CFL tubes. Fluorescent lamps or cold cathode tubes are also suitable as fluorescent tubes. Cold cathode tubes are also known by the term CCFL tubes.

The interior 50 of the housing 46 is filled with a light-conducting liquid in the form of liquid silicone oil 54, which is indicated in FIG. 9 in the form of circles and directs light emitted by the semiconductor light chips 52 to the narrow surface 16 of the light guide plate 12. At the same time, heat generated by the semiconductor luminescent chip 52 is dissipated to the outside, in particular to the walls of the housing 46, by the silicone oil 54.

The p-type GaN / n-InGaN semiconductor light emitting chip 52 irradiates ultraviolet light and blue light in a wavelength range of 420 nm to 480 nm when voltage is applied. In order to produce white light with the semiconductor luminescent chips 52, fine phosphor particles 56 are homogeneously distributed in the silicone oil 54 and are made of transparent solid-state materials comprising color centers. These phosphor particles 56 are indicated in FIG. 9 as circles, which are smaller than the circles which characterize the silicone oil 54. se. The phosphor particles 56 may each be a mixture of several different types of phosphor particles. By suitable choice of phosphor particles or of phosphor particle mixtures, therefore, the radiation emitted by the semiconductor light chips 52 radiation can be converted into a radiation having a spectrum which is adapted to a desired spectrum. If phosphor particles 56 are omitted, the lighting unit 42 emits blue light.

Several semiconductor luminescent chips 52 are electrically connected in parallel and can be supplied with voltage via two supply lines 58 and 60. For this end the supply lines 58 and 50 in externally accessible connections. The light emitting phosphor chips 52 may also be connected in series when working with a higher supply voltage.

The inner walls of the housing 46 are provided with a reflection layer 62, whereby light which is first emitted by the semiconductor luminescent chips 52 in a direction running away from the light guide plate 12 is reflected onto the same or onto its narrow surface 16.

The lighting unit 42 is arranged in FIG. 9 on the rear side 64 of the liquid crystal panel 44. Opposite the rear side 64, the liquid crystal panel 44 has a visible side 66. A liquid crystal panel, as it is used in ^¬ example in liquid crystal screens, is in and of itself known, which is why at this point to a more detailed explanation is omitted.

The illumination unit 42 is arranged such that the first main surface 14 of the light guide plate 12 extends parallel to the liquid crystal panel 44 and in the direction of the latter Rear side 64 points. Between the first main surface 14 of the light guide plate 12 and the back side 64 of the liquid crystal panel 44, an optical coupling layer 68 made of a thick silicone oil or of an elastic silicone mass is provided. The silicone material is also indicated here by circles.

The optical coupling layer 68 made of the elastic silicone composition can be obtained by adding a hardener to a more thin-flowing silicone oil. The optical coupling layer is in direct contact with the first main surface 14 of the light guide plate 12 and with the outer surface of the Flussigkristall- panel 44 on the rear side 64 in contact.

In a modification, the optical coupling layer 68 may also be a resin, for example, an epoxy resin or a polyester resin. In this case, the optical coupling layer 68 can be obtained by curing a liquid applied resin, to which a hardener has been added, as it is known per se.

By means of the illumination unit 42, a uniform high-intensity light is emitted via the first main surface 14 of the light guide plate 12, which is transmitted via the coupling layer 68 of silicone oil or a viscous silicone composition to the liquid crystal panel 44 and illuminates it from its rear side 64.

The use of the optical waveguide device 10 within a lighting unit 42 for backlighting a Flussigkristall-panel 44 is intended to be only an example of the use of the optical fiber device 10 here.

Another possibility is to use the lighting unit 42 - without liquid crystal panel 44 - as a lamp for lights from outside or inside areas. Due to the large reflection effect and the associated very good Lxchtleiteigenschaften the Lxchtleitereinrichtung 10 lighting units 42 can be created, which have relatively large dimensions, but need only bulbs 52 with low power consumption.

In a modification, the liquid-crystal panel 44 on the visible side 66 may be provided with microlenses not specifically shown here. Thus, the emerging light can be both bundled and redirected to meet the respective requirements of the lighting design. In this case, eliminates the coupling layer 68, wherein the light guide plate 12 and the Flussigkristall- panel 44 remain spaced apart.

Thus, it is possible, for example, to form a lighting unit 42 with a light guide plate 12 having a length of 5 m, a width of 10 cm to 20 cm and a thickness of 1 mm to 8 mm, wherein only bulbs with a power of 2 W to 5 W are necessary in order to be able to radiate a uniform useful light of high intensity over the first main surface 14 of the light guide plate 12. Accordingly, one or more such lighting units 42 can be used for the effective illumination of tunnels, roads or buildings, in particular industrial halls.

Another possibility is e.g. It is to use the Lichtlei- device 10 as secondary light-coupled passive Leuchtkorper in conjunction with at least one other passive Leuchtkorper, which is illustrated in Figure 10.

FIG. 10 shows a lighting system 100 with a plurality of optical waveguide devices 70 to 88, which in their Structure of the light guide device 10 correspond and partially have different dimensions and outer contours.

The narrow sides of the optical waveguide devices 72, 74, 76, 78 and 84, which are not specifically designated in FIG. 10, are in each case connected via an optical waveguide cable 90, as is known per se, to a central lighting unit 92, which is the primary one Light source is used and the emitted light is coupled via optical coupling elements 94 in the optical fiber cable 90. Thus, all optical fiber devices 70 to 88 serve as passive filaments.

The central lighting unit 92 can include, for example, semiconductor light chips 52 or other light sources, as described in connection with the lighting unit 42, which are arranged within a largely opaque housing 96.

The optical fiber devices 70 and 72 are connected to one another via a further optical fiber cable 90 '. Radiation emitted by the optical waveguide device 70 over its narrow surface is thus coupled into this optical waveguide cable 90 'and transmitted from the optical waveguide device 70 to the optical waveguide device 72.

By contrast, the optical waveguide devices 78, 80 and 82 are connected to one another via connecting pieces 98, so that light coupled into the optical waveguide device 78 is coupled into the optical waveguide device 80 and from there into the optical waveguide device 82. The optical waveguide devices 78, 80 and 82 are thus arranged in the manner of a series connection. The three optical fiber devices 84, 86 and 88 are connected to one another via corresponding connecting pieces 94. There, light coupled into the centrally arranged light guide device 84 is transmitted to the two light guide devices 86 and 88 laterally flanking the light guide device 84.

Optionally, between the opposing narrow surfaces of two optical fiber devices within a connecting piece 98, a light-conducting material, such as e.g. Silicone oil, be provided.

The light leaving the optical waveguide devices 70 to 88 via their respective first main surface 14 has an intensity which corresponds approximately to that of the luminous unit 92 or its light sources.

With such a lighting system 100, which comprises the central lighting unit 92 and a plurality of optical fiber devices 70 to 88, the latter being light-conducting connected to the central lighting unit 92 and / or one another, a considerably large area or even a building with a plurality of rooms can be illuminated ,

As a central lighting unit 92, for example, a

Light source 52 is used with semiconductor light chips, as described above in connection with the lighting unit 42, so at a power consumption of e.g. 25 watts a light intensity of 2125 lumens at the central light unit 92 can be achieved. In this case, the light-conducting devices 70 to 88 of the lighting system 100 can each emit light with an intensity of approximately 2000 lumens.

As already explained above, in the production the optical waveguide device 10, a corresponding pattern of a provided with reflection particles, screen-printable adhesive by means of a corresponding printing press on the reflector substrate 28 are printed.

The adhesive serving as the carrier material for the reflection particles is preferably clear and optically transparent after curing. In addition to the abovementioned materials epoxy resin, polyester resin or silicone material, the adhesive can also be formed from an acrylate-based material, in particular from polymethyl methacrylate, or a dispersion adhesive or a UV-curing adhesive, such as a polyacrylate.

The used optical adhesive in the cured state preferably has a refractive index which approximately corresponds to the refractive index of the light guide plate 12.

In addition to the screen printing method described above, other methods known per se can also be used. For example, ink-jet methods can be used, as used in rapid prototyping and in so-called 3D printing. Optionally, material islands of different composition, for example with regard to the density distribution of the reflection particles and optionally the admixture of pigment particles and / or phosphors, can thus also be applied to the reflector substrate 28 in one operation.

With the aid of the light guide device 10 explained above, signs or decorative lights can also be produced in another application. This will be explained below with reference to an exemplary embodiment of a sign 102, which is shown in FIG. 11. The following explanations apply mutatis mutandis to a decorative lamp right.

The sign 102 includes a slightly modified lighting unit 42, wherein the main surface 14 of the Lichtlei- terplatte 12 forms the visible surface of the sign 102. The modification consists in that the reflector substrate 28 carries an imprint 104 on its outer surface 30 facing the material islands 26. This can be any color or black and white image. The imprint 104 does not have to form an uninterrupted layer on the reflector substrate 28. The thickness of the print 104 corresponds to the thickness of the print job in per se known printing method, such as offset printing or digital printing, and is in the range of about 1 micron.

Preferably, in the sign 102 as a reflector substrate 28, a film, in particular a white plastic film used. However, the above-mentioned paper sheet or mirror foil are also suitable.

In daylight, the signpost 102 can now be used without the semiconductor light-emitting chips 52 are operated. In this case, an observer of the sign 14 sees the image of the imprint 104 shining through the layer with the material islands 26 and the light guide plate 12.

In the dark, the semiconductor light-emitting chips 52 are activated and coupled in the manner described above, white light in the light guide plate 12. The imprint 104 is then clearly visible to the viewer of the sign 102 at the points that are touched by the material islands 26. The viewer then sees the image of the imprint 104 rasterized. In the production of the sign 102, the reflector substrate 28 is provided in a manner known per se with the imprint 104 before the printing of the material islands 26.

In a modification of the sign 102, the imprint 104 can be dispensed with and the image to be displayed can be formed by a corresponding arrangement of the material islands 26 on a light or white reflector substrate 28. Alternatively, the imprint 104 may be light or white. The human eye, with active semiconductor light emitting chips 52, can detect the difference in brightness between the areas of islands of material 26 and the areas without the islands of material 26.

In this way, the islands of material 26 appear to a viewer of the sign 102 as bright areas when light is coupled into the light guide plate 12, whereas the areas between the islands of material 26 appear dark. With an appropriate arrangement of the islands of material 26, a screened image can be generated with active semiconductor light-emitting chips 52. Without light coupling, however, no image can be recognized in this case.

If instead of the planar light guide plate 12 light guide elements 12 are used with other than planar geometries, lighting devices 10 and, accordingly, signs 102 as cylinders, part cylinders, cones, truncated cone, corrugated sheets and the like can be formed.

Claims

claims

1. optical fiber device with

a) a light guide element (12) which is delimited by a first main surface (14) and a second major surface (22) spaced parallel thereto;

b) a reflection device (24), which is arranged on the side of the second main surface (22) of the light guide element (12) and by means of which light at least in the direction of the interior of the light guide element (12) is reflective,

characterized in that

c) the reflection means (24) comprises islands of material (26) made of a preferably transparent reflection material.

2. Optical fiber device according to claim 1, characterized in that the material islands (26) in

Essentially arranged regularly.

3. optical fiber device according to claim 1 or 2, characterized in that the reflection material

Includes reflection particles.

4. Optical fiber device according to claim 3, characterized in that the reflection particles comprise one or more of the following compounds: scandium oxide, lanthanum oxide, cerium oxide, preseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, Ytterbium oxide, lutetium oxide.

5. optical fiber device according to claim 4, characterized in that only reflection particles of pure scandium oxide or pure ytterbium oxide are provided.

6. optical fiber device according to one of claims 3 to 5, characterized in that the reflection material comprises a carrier material in which the reflection particles are substantially homogeneously distributed.

7. optical fiber device according to claim 6, characterized in that the carrier material is a resin, in particular an epoxy resin or a polyester resin.

8. optical fiber device according to claim 6, characterized in that the carrier material a

Silicone material, in particular an elastic silicone composition, is.

9. optical fiber device according to one of claims 1 to

8, characterized in that the material islands (26) contact at least the second main surface (22) of the light guide element (12).

10. optical fiber device according to one of claims 1 to

9, characterized in that the reflection device (24) comprises a reflector substrate (28), which is arranged on the side remote from the light guide element (12) (12) of the material islands (26).

11. Optical fiber device according to claim 10, characterized in that the material islands (26) of the

Reflector substrate (28) are worn.

12. Optical fiber device according to claim 10, characterized in that the reflector substrate (28) has a colored or black-and-white imprint (104), in particular on the material islands (26) facing side carries.

13. Optical fiber device according to claim 10 or 12, characterized in that the reflector substrate (28) from the light guide element (12) is spaced.

14. Optical fiber device according to claim 13, characterized in that the distance between the reflector substrate (28) and the light guide element (12) about 1 .mu.m to about 1 mm, preferably about 5 .mu.m to about 100 .mu.m, more preferably about 8 .mu.m to about 20 μm and more preferably about 14 μm.

15. Optical fiber device according to one of claims 10 to 14, characterized in that the reflector substrate (28) is a white paper sheet (28).

16. optical fiber device according to claim 15, characterized in that the paper sheet (28) a

Basis weight from 50 g / m ² to 200 g / m ² , preferably from 80 g / m ² to 170 g / m ² , more preferably from 100 g / m ² to 150 g / m ² and particularly preferably from 120 g / m ² Has.

17. Lightguide device according to one of claims 10 to 16, characterized in that the reflection device (24) comprises a reflection layer (36), in particular a mirror foil or a reflection layer (36) of metal, in particular of aluminum, which on the the light guide element (12) remote from the reflector substrate (28) is arranged.

18. Optical fiber device according to one of claims 1 to 17, characterized in that material islands (26) in

Supervision in the direction of the second main surface (22) of the light guide element (12) have an outer contour which corresponds to the outer contour of a circle, a semicircle, an ellipse, a rectangle, a square or other polygon.

19. Optical fiber device according to one of claims 1 to 18, characterized in that material islands (26) in plan view in the direction of the second main surface (22) of the light guide element (12) has a radial extent of about 0.01 mm to about 100.0 mm , preferably from about 0.05 mm to about 10.0 mm, more preferably from about 0.1 mm to about 5.0 mm, and particularly preferably from about 0.2 mm to 1.0 mm.

20. Optical fiber device according to one of claims 1 to

19, characterized in that the distance between two islands of material (26) is about 0.01 mm to about 100.0 mm, preferably about 0.05 mm to about 10.0 mm, more preferably about 0.1 mm to about 3, 0 mm, and more preferably about 0.2 mm to 1.0 mm.

21. Optical fiber device according to one of claims 1 to

20, characterized in that the light guide element

(12) is made of glass or acrylic glass or epoxy resin.

22. Lighting device with a passive lamp

(10; 70, 72, 74, 76, 78, 80), in which light emitted by primary lighting means (52; 92) can be coupled in, characterized in that the passive lighting body (10; 70, 72, 74, 76, 78, 80) is a light guide device (10; 70, 72, 74, 76, 78, 80) according to one of claims 1 to 21.

23. Lighting device according to claim 22, characterized in that of the lighting means (52; 92)

emitted light in the light guide element (12) can be coupled.

24. Lighting device according to claim 22 or 23, characterized in that at least one further passive luminous body (10; 70, 72, 74, 76, 78, 80) is provided.

25. A method for producing a light guide device (10) according to any one of claims 1 to 20, comprising the following steps:

a) providing an adhesive material;

b) mixing the adhesive material with reflection particles, so that the reflection particles in the

Carrier material are distributed substantially homogeneously;

c) applying material islands (26) of the adhesive material with reflection particles distributed therein to a substrate (28);

d) coating a light guide element (12) with the substrate (28) carrying the material islands (28) such that the islands of material (26) between the substrate (28] and the light guide element (12) are arranged.

26. The method of claim 25, wherein the substrate

(28) is a plastic film, in particular a white plastic film, a mirror foil or a sheet of paper.

27. The method according to claim 25 or 26, characterized in that the adhesive material is formed from one of the following materials: epoxy resin; Polyester resin; Silicone material, in particular an elastic silicone compound; acrylate based material, especially polymethyl methacrylate; Dispersion adhesive or CJV-curing adhesive, such as a polyacrylate.

28. The method according to any one of claims 25 to 27, wherein the substrate (28) before applying the material islands (26) in step c) is provided with an imprint (104).

29. The method of claim 28, wherein the imprint

(104) is formed of a bright material and flat.

30. The method of claim 28, wherein the imprint (104) is adapted to render a black-and-white or a color image.

31. The method according to any one of claims 25 to 30, wherein the application of the material islands (26) on the substrate (28) in step c) by means of a screen printing process.

32. The method according to any one of claims 25 to 31, wherein the coating of the light guide element (12) with the material islands (26) carrying the substrate (28) in step d) by means of a lamination process.