DE102011015161A1 - LED lighting device for illuminating e.g. interior of aircraft, has light guide comprising core region made of multi-component glass containing divalent iron and/or trivalent iron of predetermined amount - Google Patents

Abstract

The device (10) comprising rigid rod-shaped light guide (1) with end face in which an LED is inserted. A radiation coupling unit is provided in outer circumferential surface area of light guide. The radiation emitted from the LED is irradiated in the light guide in the operating state, and is reflected from radiation coupling unit and passed through light guide laterally from the light guide. The light guide has core region made of multi-component glass containing divalent iron and/or trivalent iron (50 ppm). The illumination profile that corresponds to fluorescent tubes is achieved.

Description

The invention relates to an LED lighting device and its applications. LEDs (Light Emitting Diodes) are becoming increasingly important as a light source, on the one hand because they are considered energy-efficient, on the other hand because they have a long service life and thus can be expected to require little maintenance.

An LED is an electronic semiconductor device. When supplied with electricity, it emits electromagnetic radiation whose wavelength can be in the infrared, visible and / or ultraviolet spectral range. The term LED used in the present specification includes no limitation to a particular wavelength of the emitted radiation.

It is also possible that a plurality of emitting active elements are arranged on a chip, which is also referred to as LED in the sense of the present description. Furthermore, no limitation of the coherence length of the emitted radiation is associated with the term LED used, so that laser diodes are likewise included therein.

A disadvantageous feature of LEDs for lighting applications, however, is that commercially available LEDs are provided in an encapsulation that includes a reflector and / or a lens that emits the radiation emitted by the LED forward at a relatively small opening angle. For the illumination of larger areas, therefore, fluorescent tubes are still popular. However, these have the disadvantage that they can break easily, which is particularly problematic in applications where strong vibrations or other mechanical stresses may occur, but also that they require a relatively high ignition voltage, which require correspondingly expensive electronic components in the power supply and can also emit electromagnetic interference. Another disadvantage of fluorescent tubes is that they emit heat and UV radiation at their luminous area.

In order to avoid the latter disadvantage in particular suggests the US 4,733,332 to couple the light emitted by an incandescent or gas discharge lamp light in the end face of a glass rod, which is provided with a line-shaped diffusion pattern on its lateral surface. The glass rod acts as a light guide for the coupled light, the diffusion pattern decouples it from the glass rod in such a way that it reflects the incident light into the glass rod, passes through it and can be coupled out laterally on the opposite side of the glass rod. In this way, a line-shaped lighting profile with an opening angle, which may correspond to a fluorescent tube with reflector. Apart from the usual disadvantages of the proposed light sources, the proposed device has the disadvantage that the color and in particular the intensity of the emitted light depends on the transmission of the glass rod. For this reason, the use of quartz glass is recommended. However, this is very expensive to produce and correspondingly expensive. Apart from that, quartz glass is a very brittle material, which is also easy to break and has a small critical angle for total reflection, making it difficult to couple light into silica glass fibers.

Area emission profiles are achieved by the edge-lit information panels known from the prior art. In the DE 10 2009 001 170 A1 For example, a plurality of LEDs are arranged at the edges of a transparent plate. The light of the LEDs shines into the edges and is guided in the plate. To decouple it from the plate, coupling structures must be created on the plate. These are usually generated for example by sandblasting. As material for the plate, plastics or mineral glass are provided. This device has the disadvantage that the plastics are not flameproof. In particular, in applications with high fire safety requirements, such as in aircraft interiors, they can be used at most by exemption regulations. If, on the other hand, the proposed mineral glass is used, only a colored light can be obtained by specific transmission of the glass and, apart from that, planar structures made of glass are much more susceptible to breakage than rod-shaped structures.

Against this background, it is an object of the invention to provide an LED based lighting device which can illuminate larger areas, is flame resistant and can provide pure white light.

The object is achieved by the lighting device according to the main claim. Preferred embodiments and applications emerge from the dependent claims.

The LED lighting device according to the invention includes a rigid rod-shaped light guide, which has at least one end face. This is assigned at least one LED. In the outer peripheral surface area of the rigid rod-shaped optical waveguide there are means for decoupling radiation. In the operating state, ie when current flows through the LED, the radiation emitted by the at least one LED is radiated through the end face into the light guide and guided by the latter by total reflection. The means for decoupling the radiation ensure that the radiation impinging on them reflected into the light guide and laterally, while passing through the light guide, that is laterally or at the outlet from the outer peripheral surface, is coupled out of the light guide. The light guide consists at least in its core region of a multi-component glass containing at most 50 ppm (parts per million) Fe ²⁺ and / or Fe ³⁺ .

A multi-component glass, also called mineral glass, is melted from more than one raw material and contains the oxides of more than one chemical element. This differentiates it from a quartz glass, which consists only of SiO ₂ . The inventors have recognized that the iron content of the glass is decisive for the fact that the optical fiber itself does not shift the color spectrum of the radiation conducted in it, which would make emission of pure white radiation impossible. In other words, with glass optical fibers containing a higher proportion of Fe ²⁺ and / or Fe ³⁺ 50 ppm, if white light were passed in them, a light stinging effect would be observed for lighting applications is undesirable or at least disadvantageous.

The Fe ²⁺ and / or Fe ³⁺ may be present in the glass in the form of ions, or else in the form of oxides, for example FeO and / or Fe ₂ O ₃ . Iron often gets into glass due to contamination of the raw materials used in melting the glass, but also through the use of steel components that come in conjunction with the molten glass. Therefore, particularly pure raw materials are preferably used in the production of the glass rods which are part of the lighting device according to the invention.

According to the invention, the means for decoupling the radiation are applied in the outer peripheral region of the rigid rod-shaped optical waveguide. In the simplest case, the light guide consists of a glass rod from the described glass. The radiation is conducted in the glass rod at the interface of the glass rod by total reflection against the surrounding medium, generally air. The means for decoupling the radiation are in this simplest case directly outside of the glass rod and thus mounted on its outer peripheral surface.

But it is also possible that the rod-shaped light guide consists of a core region of said glass, which is covered by another glass with a lower refractive index. The total reflection required for the light pipe then takes place at the interface between the core and the cladding glass with the lower refractive index. The means for decoupling the radiation may be mounted on the core glass and covered by the cladding glass, or with a suitable choice z. As the refractive indices of the glasses on the cladding glass itself. Compared to the core, the thickness of the or the surrounding shells but relatively low. For this reason, the term outer peripheral surface area in the sense of the invention not only the outer peripheral surface of the light guide, but a surface which is located in the outer periphery of the light guide, ie at a certain depth near the surface. Thus, it is also possible and encompassed by the invention that the means for decoupling the radiation and / or the light guides of at least one further layer, for. As a protective layer, are covered, regardless of whether the means for coupling the radiation are directly on the core of said glass or on a surrounding cladding glass.

In the simplest form, means for decoupling the radiation are printed on the lateral surface and / or glued and / or sprayed. You are then as a layer directly on the outer peripheral surface. But it is also possible to produce the means for coupling the radiation by structuring the lateral surface, for. B. by roughening. It is also possible to apply layers, for example, reflective layers, by physical vapor deposition (PVD), plasma-induced chemical vapor deposition (PICVD) and / or sputtering. The easiest way, however, is the printing or spraying of, for example, white color. Depending on the application, however, all conceivable other colors are possible. As a result of the at most slight discoloration of the incident light by the light guide according to the invention, the color emitted by the illumination device can thus be adjusted simply by the color of the means for decoupling the radiation. Alternatively, a color filter can be introduced into the beam path.

The rigid rod-shaped optical fiber preferably has a round cross section and is straight. However, as well as the invention, the term encompasses other cross-sectional geometries and / or curved and / or kinked optical fibers or rods.

Preferably, the rigid rod-shaped light guide, at least in its core region of a glass containing: 70% -85% SiO ₂ , 8% -20% B ₂ O ₃ and individually or in total 2% -8% Na ₂ O and / or K ₂ O and / or Li ₂ O. This means that not every one of the alkali metals mentioned must be present in the glass, but at least one in said minimum amount. Further preferred optional components are up to 7% Al ₂ O ₃ and individually or in total up to 5% MgO and / or CaO and / or BaO and / or ZnO. All percentages in this specification are given in weight percent (wt.%) Based on oxide. As described, the glass according to the invention contains in total at most 50 ppm Fe ²⁺ and / or Fe ³⁺ , preferably at most 20 ppm, particularly preferably at most 10 ppm. Other components are optional, but the proportion of heavy metals such as Pb, Cd, Hg and Cr is preferably less than 100 ppm.

Such a glass is characterized by its excellent resistance to attack by water, acids and alkalis. In particular, it corresponds to a water resistance class HGB1 according to ISO 719 , an acid resistance class S1 after DIN 12116 and an alkali resistance class A2 ISO 695 , During operation of the lighting device, the rigid rod-shaped light guide can very easily come into contact with water, acids or alkalis, for example in the form of atmospheric moisture, vapors of operating materials and / or solvents and / or cleaning agents. A lower resistance of the glass of the light guide could lead to blindness thereof, whereby the light guide could be limited in its function and in the end the lighting device could become unusable. Therefore, the excellent durability of the preferred glass results in a long life expectancy of the lighting device, even under adverse circumstances.

Particularly preferably, the rigid rod-shaped light guide consists, at least in its core region, of a glass which contains: 75% -85% SiO ₂ , 8% -15% B ₂ O ₃ , individually or in total 2% -8% Na ₂ O and / or K ₂ O and / or Li ₂ O, optionally 0% -5% Al ₂ O ₃ and optionally individually or in total 0% -2% MgO and / or CaO and / or BaO and / or ZnO. The aforementioned condition of the contents of Fe ²⁺ and / or Fe ^{3+ of} course also applies to these particularly preferred glasses.

The glass preferably has a modulus of elasticity E, also called Young's modulus, of at most 66 × 10 ³ N · mm ^-2 . The smaller the numerical value of E is, the lower the stiffness of the relevant component, in this case of the rigid rod-shaped optical waveguide made of said glass. It has been found that the modulus of elasticity E correlates with the resistance of the glass or in this case of the rigid rod-shaped optical fiber to vibrations, in such a way that the less rigid the optical fiber is, the better it will withstand the vibrations. This means that it is desired that the value of the elastic modulus E of the glass of the rigid optical fiber should be as low as possible in order to ensure a good vibration resistance. Vibrations can damage the rigid optical fiber made of glass in particular in that cracks form in it, which can lead to breakage of the optical fiber and / or to spalling of material. Both are undesirable and can lead to failure of the lighting device. As compared to the above-mentioned value for the modulus of elasticity E of at most 66 · 10 ³ N · mm ^-2 , quartz glass has a modulus of elasticity E of 72.5 · 10 ³ N · mm, as is known for lighting devices of the prior art ^{. 2} on. As already described, it is much more brittle than the multicomponent glass according to the invention and can withstand vibration loads less well.

According to the invention, it is possible to irradiate the radiation emitted by the at least one LED directly or through a lens system through the end face of the light guide, or else between the at least one LED and the end face of the rigid rod light guide at least one fiber optic flexible light guide to place. In the operating state, the radiation emitted by the at least one LED according to this embodiment is transported by the flexible fiber optic light guide to the rigid rod-shaped light guide. Lenses and / or lens systems may be placed at any suitable locations in front of and / or beyond the interfaces of the flexible fiber optic light guides or the rigid rod light guide. Particularly advantageously, the flexible fiber optic light guide is used to redirect and / or distribute the radiation emitted by the LED. This can be particularly advantageous if only small depths for the LED and the lens systems are available. Therefore, a particularly preferred variant of the illumination device provides that, in the operating state, the radiation emitted by the at least one LED is conducted through a lens system into the flexible fiber-optic light guide, and this directly, for example by an optical cement and / or a suitable bond and / or or a suitable socket is connected to the rigid rod-shaped light guide. The flexible one Fiber optic light guides may preferably be bent 90 ° or 180 ° to redirect the light in that direction.

In addition to the deflection of the light and the variation of the design of the flexible fiber optic light guide, however, can also be advantageously used to mechanically decouple the rigid rod-shaped light guide and the light generating unit, namely the at least one LED and the optional optical system. In this way, vibrations of the light generating unit can be kept away from the rigid rod-shaped light guide or vibrations of the rigid rod-shaped light guide from the light generating unit.

A common problem with the use of LEDs, especially bright high-power LEDs, is their heat development. If the LED is too hot, it can be destroyed in extreme cases or emit less useful radiation. Another effect due to the operating temperature is the so-called Colorshift, which means that the spectrum of the emitted radiation of the LED changes depending on the operating temperature. In a further preferred embodiment, it is therefore provided that the at least one LED is mounted in a housing body, whose wall serves as a heat sink for the LED and means for holding the flexible or the rigid rod-shaped light guide or directly with means for holding the flexible or the rigid rod-shaped light guide is connected. The housing body in this case fulfills a dual function, namely to hold the at least one LED and the rigid rod-shaped light guide, and at the same time to radiate over its surface the heat generated during operation by the at least one LED. In this way, the heat produced by the LED can be transported away, so that it takes no damage and / or as little loss of efficiency and / or has as little as possible Colorshift.

The housing body itself can of course also be connected to other objects, for example, to attach the entire lighting device at the desired location. For fixing the LED lighting device to other objects, therefore, a mounting body is provided which performs this function. Preferably, this mounting body as well as the aforementioned housing body serves as a heat sink for the at least one LED.

As described, heat may be generated during operation of the LED lighting device, but it is also possible that the LED lighting device is in environments that may experience large temperature fluctuations. The components of the illumination device, in particular the rigid and / or flexible light guide and the means for holding the rigid light guide and / or the housing body or the elements of the light generating unit generally have different thermal expansion coefficients. This has the consequence that the components mentioned can move against each other with temperature changes. If they collide, these components may be damaged and / or misaligned. Therefore, in a particularly preferred embodiment, the means for holding the flexible or the rigid rod-shaped light guide are formed so that an axial displacement of the flexible or the rigid rod-shaped light guide is possible. By this measure, it is also possible to compensate for manufacturing tolerances in particular with respect to the length of the rigid optical fiber and / or the housing body. Likewise, the assembly is facilitated.

Particularly preferably, the means for holding the flexible or the rigid rod-shaped light guide are further designed so that they also absorb vibrations of the rigid rod-shaped light guide in the direction perpendicular to its axis. This can be achieved by at least some of the means for holding substantially perpendicular to the axis of the rigid rod-shaped light guide are deflectable and return to its original position after the deflection. In addition to the design of these means for holding this can be made possible by a suitable choice of materials, for example made of thermoplastic materials.

The construction described makes it possible in a particularly preferred embodiment that the rigid rod-shaped optical fiber is rotatably mounted relative to the housing body about its axis, so that the usable light can be coupled out regardless of the location of mounting the housing body and / or the mounting body of the light guide. In conventional lighting devices with fluorescent tubes as the illumination means, the usable light is emitted in the maximum intensity in the direction of the reflectors. The reflectors are part of such lighting devices, so that their positioning must be taken into account during their installation. This impairs the freedom of design of the mounting locations and is particularly disadvantageous for example in aircraft cabins or in the interior of trains. In the illumination device according to the invention, the reflector is as it were represented by the means for decoupling the radiation and arranged on the rigid optical fiber, so that this opposite the housing and / or the mounting body can be rotated, whereby in the positioning of the lighting device fewer parameters are taken into account and greater freedom exist.

Preferably, the rotation of the rigid rod-shaped optical waveguide and thus the adjustment of the illumination location during assembly of the illumination device according to the invention is performed. Subsequently, it may be undesirable that the rigid rod-shaped optical fiber is twisted axially. Therefore, a particularly preferred embodiment provides that the rigid rod-shaped light guide is connected by means of at least one support structure with the mounting body. The support structure preferably has means for fixing the rigid rod-shaped light guide, so that the rotation about its axis is prevented. The means for fixing can be realized in various ways, for example by a Verklemmvorrichtung, or else by clamping screws, for example by grub screws etc. The use of the support structure can also bring about the further advantage that the rigid rod-shaped light guide at loads perpendicular to its axis, which may occur during assembly and / or adjustment and / or vibrations during operation, is supported by the support structure. As a result, the maximum deflection of the rigid rod-shaped light guide can be limited and its breakage can be prevented.

The amount of radiation provided by the illumination device according to the invention and thus also the light intensity can be increased by at least two straight rigid rod-shaped light guides arranged parallel to each other connected to a mounting body and are independently rotatable about its axis relative to the housing body and / or the mounting body. The usable light is then decoupled from the light guide regardless of the location of the mounting of the housing body and / or the mounting body and the entire beam angle of the LED lighting device is adjustable in this way. This corresponds to a multistatic system, so to speak. Two, three or more rigid optical fibers can be provided.

The optical system of the LED illumination device preferably consists of a lens system, which particularly preferably consists of two aspherical lenses whose focal lengths are matched to the numerical aperture of the optical waveguide into which the radiation is coupled. Are the lenses in front of the flexible light guide, d. H. When the radiation emitted by the LED is coupled into the flexible light guide, the optical system is tuned to the numerical aperture of the flexible light guide. If the lenses are located in front of the rigid optical waveguide so that the radiation emitted by the LED is guided by the lenses directly into the rigid optical waveguide, their focal lengths are matched to the numerical aperture of the rigid optical waveguide. As is known to those skilled in the art, the numerical aperture is the sine of the acceptance angle of the optical fiber. If this vote is dispensed with, in most cases the radiation emitted by the LED can not be completely coupled into the optical waveguide and the efficiency and / or the maximum brightness provided by the illumination device is lower.

Preferably, a lens of the described lens system is in combination with the LED. Mostly this will

then already applied in the manufacture of the LED in the encapsulation of the LED with. The other lens is preferably mounted in a socket, which is connected to the housing body and thus also mounted in this.

The LED is preferably an LED chip, which in particular comprises an RGB, RGBA, RGBW or RGGB chip. Furthermore, this sensor may be associated with a sensor (and measures described below by way of example) for controlling the color locus and / or the brightness of the emitted radiation of the LED. It is possible that the sensor is located on the LED chip, or it may be integrated at another point in the beam path. It is also possible that the sensor is located at any point of the rigid and / or optionally existing flexible light guide. The LED and / or the chip is usually associated with an evaluation and control electronics, which determines the color location and / or brightness, whereupon the LED or the LED chip are controlled so that certain operating states of the LED can be set. By targeted control of the elements of the chip is a color mixing of the emitted radiation. In this way, for example, light of any color can be emitted from the LED and thus the illumination device. However, as already described with regard to the color shift, the color location can vary depending on the ambient conditions, in particular the temperature, but also on the age of the LED. This variation can not be determined, which is why the sensor should measure the intensity of the radiation and its color location. By taking these values into account when controlling the LED or LED chips, a reproducible and permanently stable color location as well as a reproducible and permanently stable intensity of the radiation emitted by the illumination device can be achieved.

The invention includes not only lighting devices with straight rigid rod-shaped optical fibers, but also those with arbitrarily bent rigid Lichtleitetrn.

It is particularly preferred if each end face of the rigid optical waveguide is assigned at least one LED and, in the operating state, radiation is coupled into the optical waveguide through each of these end faces. This can lead to further increased achievable intensities of the illumination device. Particularly preferably, the said LEDs are located in front of each end face in the housing bodies described and have the described lens system. The at least two housing bodies may be mounted on a common mounting element. As a result, a particularly large surface can be achieved, which as described can be used to dissipate the heat generated by the LEDs and thus to cool the LEDs.

In order to produce the most homogeneous possible emission profile, the means for decoupling the radiation are formed by a coating applied at least in sections to the rigid rod-shaped optical fiber, which is preferably formed by varying its density and / or structure and / or geometric pattern and / or composition in that, in the operating state, the decrease of the intensity of the radiation conducted in the light guide, which increases with the distance to the LED, is at least partially compensated. Thus, the impression of a largely homogeneously radiating light source can be achieved for the user. All methods suitable for applying the coating are possible, but preference is given to printing methods, in particular screen or pad printing.

The lighting device according to the invention has the particular advantage that flame-resistant materials are used, in particular the rigid optical fiber made of glass. This is by the selection of the glass also vibration resistant. This makes the lighting device particularly suitable for use in interiors of aircraft subject to special safety regulations. Particularly preferred applications are therefore carried out in aircraft cabins and / or aircraft cargo holds.

Their advantages are also useful in the interiors of other means of transport such as trains or automobiles (passenger cars as well as trucks).

Further advantageous and preferred uses are generally light elements of vehicles, preferably daytime running lights and / or position lights on the front of automobiles and / or as an element whose headlights, or as an element of the taillight of automobiles.

A further preferred use of the illumination device according to the invention takes place as an element of a designer lamp and / or household lamp and / or office lamp. Other preferred applications are shelf lighting, especially on store shelves, cabinets and other furniture.

The invention will be further clarified below with reference to the drawings. The drawings are schematic, the scales and dimensions do not have to match the actual objects. Show it:

1 : The longitudinal section through a described lighting device.

2 : The longitudinal section through another described illumination device.

3 : The principle of light extraction.

4 : The longitudinal section through another described illumination device.

5a : The cross section through a housing body.

5b : The perspective view of a housing body.

6a : The cross-section of means for holding the rigid rod-shaped light body.

6b : The longitudinal section of means for holding the rigid rod-shaped light body.

6c : The perspective view of means for holding the rigid rod-shaped light body.

7 : The perspective view of a support structure.

8th : An embodiment of the illumination device according to the invention.

9a : A described lighting device with a curved rigid rod-shaped light guide.

9b : A described lighting device with a curved rigid rod-shaped light guide.

9c : A described lighting device with a curved rigid rod-shaped light guide.

10a : An automobile headlight with a described illumination device.

10b : A tail light of an automobile with a described illumination device.

11 : An aircraft interior with a described illumination device.

1 shows the principle of the LED lighting device according to the invention ( 10 ) in a schematic longitudinal section. In operation, radiation ( 5 ) from the LED ( 3 ) emitted. The LED ( 3 ) is in front of the face ( 2 ) of the rigid rod-shaped light guide ( 1 ) arranged. For coupling the radiation ( 5 ) in the light guide is a lens ( 6 ) used. In the figures, the lens ( 6 ) representative of any suitable lens system. As can also be seen in the figure, the lens system can also be partially integrated on the LED ( 3 ) are located. It can also have any number of lenses. As already described, aspherical collimator systems have proven to be particularly suitable for the coupling of LEDs ( 3 ) emitted radiation in optical fibers ( 1 ) made of glass. The optical parameters of the lens system include the emission characteristics of the LEDs ( 3 ) but also on the refractive index and thus the numerical aperture of the light guide ( 1 ) dependent. In the outer peripheral surface area of the light guide ( 1 ) are means for coupling the radiation ( 4 ), which in the operating state of the LED ( 3 ) is emitted. In the simplest case, these means for decoupling the radiation ( 4 ) as also already described on the outer peripheral surface of the light guide ( 1 ) or sprayed on, the light guide ( 1 ) is a coat-free rod of the described glass. Meets in the light guide ( 1 ) guided radiation on the means for decoupling ( 4 ), it is reflected into the light guide into, passes through it and is laterally decoupled from this. The decoupled radiation ( 5 ) is the useful radiation or shortly the light that the user of the lighting device ( 10 ) is made available.

In 2 is an embodiment of the LED lighting device ( 10 ), in which in the operating state in each of the end faces ( 2 ) of the rigid rod-shaped light guide ( 1 ) from the LED ( 3 ) emitted radiation ( 5 ) is coupled. As a result, the maximum achievable illuminance can be increased, but also achieve a more homogeneous illumination profile. It should be pointed out once again that the rigid rod-shaped light guide ( 1 ) is not limited to straight rods in the sense of the invention, but that they can also be bent. Similarly, their cross-sectional area does not have to be circular.

The principle of the operation of the LED lighting device according to the invention ( 10 ) is determined by 3 clarified. The operating state of the LED ( 3 ) emitted radiation ( 5 ) is due to total reflection in the rigid rod-shaped light guide ( 1 ) guided. Does the radiation hit the means for decoupling ( 4 ), which are located in the 3 on the outer peripheral surface of the light guide ( 1 ) and thus located in the outer peripheral surface area, it is in the Lichtleier ( 1 ) is reflected in it. As a result, the reflected rays pass through the light guide ( 1 ) and strike in a significant proportion at an angle to the wall of the light guide ( 1 ), which (measured from the tangent of the wall of the light guide ( 1 )) is greater than the angle of the total reflection, so that they are coupled out through the wall of the light guide and so are available for lighting purposes. It may well be desirable that a certain proportion of the rays at an angle to the wall of the light guide ( 1 ), which is smaller than the angle of total reflection. This ensures that not all the radiation immediately from the light guide ( 1 ), but a lighting profile is achieved which corresponds to the shape of the means for decoupling ( 4 ), preferably a line-shaped (including curved lines) illumination profile. The illumination profile itself, ie the intensities of the illumination device ( 10 ) emitted radiation ( 5 ) in certain places, can also be described as described by the design of the means for decoupling ( 4 ) of the radiation.

The LED ( 3 ) is preferably in a housing body ( 30 ), whose cross-section is exemplified in 5a is shown. The figure shows a housing body ( 30 ), which for the embodiment of the illumination device ( 10 ) is determined, in which two rigid rod-shaped optical fibers ( 1 ) are arranged side by side. The housing body ( 30 ) is preferably made of a thermally conductive material, in particular a metal (including alloys of metals). Particularly preferred are aluminum and / or copper and / or brass and / or steel, in particular stainless steel. In the recesses of the housing body ( 30 ), the LEDs ( 3 ) and preferably also the lens system ( 6 ) to be assembled. It is envisaged that the LEDs ( 3 ) in the housing body ( 30 ) are mounted in thermal contact with the housing body ( 30 ), so that this in the operating state of the LEDs ( 3 ) dissipate heat produced and can radiate over its surface. In this way, the housing body ( 30 ) as a cooling element for the LEDs ( 3 ). To enhance this effect, the housing body can take measures to increase its surface area ( 31 ), which in the 5a as cooling fins ( 31 ) are formed. Likewise, it can be provided that the housing body ( 30 ) via assembly structures ( 33 ), which simply attaches it to a mounting body ( 50 ) connectable. Preferably, the mounting structures are also in thermal contact with the housing body ( 30 ) so that the LEDs ( 3 ) produced heat through the assembly structures ( 33 ) also in the mounting body ( 50 ) is derivable. Particularly preferred and in the 5a shown is the housing body ( 30 ) therefore made in one piece. Various manufacturing methods of the housing body are possible, as an example be called milling of a block of material and / or compression molding.

5b shows the perspective view of the housing body ( 30 ). In the recesses ( 35 ) of the housing body ( 30 ) are the LEDs ( 3 ), the optical system ( 6 ) as well as the means for holding ( 20 ) of the light guide ( 1 ) mountable.

The means for holding ( 20 ) of the rigid rod-shaped light guide ( 1 ) are in the 6a to 6c shown. 6a shows a cross section for the embodiment with two adjacent light guides ( 1 ), which belong to the in the 5a and 5b shown housing body ( 30 ) fit. The rigid rod-shaped light guide ( 1 ) is in the recess ( 25 ) and we through the movable terminals ( 22 ) held. The clamps are made of a material, such as a thermoplastic, and geometrically designed so that they z. B. by bending to movements of the light guide ( 1 ) are perpendicular to its longitudinal axis capable. The movable clamps ( 22 ) are also designed by the choice of materials and / or their geometric design so that they return to their original position after a deflection. In this way, vibrations of the light guide ( 1 ), as used in the operation of the lighting device ( 10 ) can be intercepted. The maximum deflection of the light guide ( 1 ) perpendicular to its longitudinal axis is determined by the rigid clamps ( 21 ) Are defined. These are designed so that they can be used with normal force, as z. B. occurs at vibration loads, not substantially perpendicular to the longitudinal axis of the light guide ( 1 ). They therefore serve, so to speak, as a vertical stop for the light guide ( 1 ). Therefore, due to the rigid clamps ( 21 ) formed diameter in the recess ( 25 ) greater than that due to the flexible clamps ( 22 ).

Like in the 6b can be seen, the rigid clamps ( 21 ) preferably designed so that they solid by material use with the main body of the means for holding ( 20 ) are connected. Within the recess ( 25 ) they preferably have a structure ( 23 ), which serves as an end stop for the horizontal displacement of the rigid rod-shaped light guide ( 1 ) serves. This is preferred by clamping forces in the means for holding ( 20 ) holding a horizontal displacement of the optical fiber ( 1 ) enable. In this way, the lighting device ( 10 ) tolerant to the thermal expansion of the light guide ( 1 ) and / or the other components of the illumination device ( 10 ), but also the mounting of the illumination device ( 10 ), because the length of the optical fibers and their horizontal positioning need not be met with the highest accuracy requirement. The means for holding ( 20 ) ensure by the horizontal displacement of the light guide ( 1 ) so to speak for a fault tolerance during operation and installation of the illumination device ( 10 ). The end stop ( 23 ) limits the horizontal displacement and thus protects the optical system ( 6 ) and / or the LEDs ( 3 ) against misalignment and / or damage that may occur when in contact with the end faces ( 2 ) of the light guide ( 1 ) would come. The end stop can also be realized by other measures.

6c is a perspective view of the means for holding ( 20 ) of the 6a and 6b , Based on this 6c It is readily apparent that the means for holding preferably in the recesses ( 35 ) of the housing body ( 30 ) to be assembled. The means for holding ( 20 ) may preferably be made of a plastic, for example by casting, in particular injection molding.

Through the holder of the light guide ( 1 ) in the flexible terminals ( 21 ), it is also possible and an advantage of the illumination device ( 10 ), the light guides with the means for decoupling ( 4 ) about the axis of the light guide ( 1 ) to twist z. B. adjust the location of the maximum illuminance according to the user wishes. This setting is preferred during assembly of the illumination device ( 10 ) in the user environment. During operation, however, an unwanted twisting is often prevented. For this reason, it provides a particularly preferred embodiment of the lighting device that the optical fiber ( 1 ) with the in 7 schematically represented support structure ( 40 ), which in turn somewhere with the mounting body ( 50 ) or another fixed point. Like in the 7 shown, the light guide rests ( 1 ) preferably in the receiving structures ( 42 ) of the support structure ( 40 ). These can also be designed such that they have a clamping effect on the light guide (FIG. 1 ), which hinder or prevent its deflection perpendicular to its axis. However, this is still a twist of the light guide ( 1 ) possible around its axis. In order to prevent these as well, the illustrated support structure sees means for fixing ( 41 ) of the light guide, which according to the 7 preferably as a press wedge ( 41 ) are designed. If the press wedge ( 41 ) is pressed into its holder, a force is applied to the receiving structures ( 42 ) and its inner wall on the light guide ( 1 ), if it is in the receiving structures ( 42 ) is mounted. The clamping force is so great that the rotation of the light guide ( 1 ) is prevented around its axis and this so firmly but detachable with the support structure ( 40 ) connected is. The jamming of the light guide ( 1 ) in the reception structures ( 42 ) can advantageously take place when the axial rotation of the light guide after assembly of the lighting device ( 10 ) is adjusted at the installation site.

Preferably, the support structure ( 40 ) also assembly structures ( 43 ), which they easily with a mounting body ( 50 ) connectable.

The support structure ( 40 ) has the further advantage that by her the bending of the light guide ( 1 ) is limited perpendicular to its axis. Such bends can be caused in particular by vibrations of the illumination device ( 10 ), but also by force of assembly personnel and / or users. If the deflection is too great, the optical fiber may break from the glass material described herein. This problem becomes more significant the longer the light guide ( 1 ). The use of a support structure ( 40 ) also allows the use of long light guides ( 1 ), even over lengths of 70 cm, in an environment in which strong vibrations are to be expected, for example in an aircraft interior, in automobiles and / or other means of transport such. B. trains. The support structure may advantageously consist of a plastic material and z. B. are produced by injection molding.

In 8th is a schematic and perspective an advantageous embodiment of an LED lighting device according to the invention ( 10 ). This figure also represents the embodiment. This lighting device ( 10 ) has two parallel rod-shaped optical fibers ( 1 ) from said glass. The light guides ( 1 ) are by means of the unseen means of holding ( 20 ) in each case a housing body ( 30 ) at the ends of the light guides ( 1 ) held. In the housing bodies ( 30 ) are also not visible LEDs ( 3 ) and optical systems ( 6 ) assembled. The housing body ( 30 ) are on a mounting body ( 50 ) and connected to this. If the lighting device ( 10 ) attached to the place of use, this can be achieved simply by mounting the mounting body ( 50 ) take place at this location. The illustrated illumination device ( 10 ) also has two support structures ( 40 ), which with the mounting body ( 50 ) are connected. This is preferably made of a metal, also from the LEDs ( 3 ) to be able to dissipate heat produced during operation.

The support structures are preferably located at positions of the mounting body ( 50 ), so that approximately equal distances between the support structures ( 40 ) and the housing bodies ( 30 ) be respected. The light guides ( 1 ) are fixed by the means for fixing ( 41 ) with the support structures ( 40 ) and thus with the mounting body ( 50 ) connected. The means for fixing ( 41 ) prevent unwanted twisting of the optical fibers ( 1 ) around its axis, but allow as well as the means for holding ( 20 ) the light guide ( 1 ) in the housing bodies ( 30 ) a movement and / or extension of the optical fibers ( 1 ) along its longitudinal axis.

The connection between housing bodies ( 30 ) and mounting body ( 50 ) can be done by any suitable method, for example by jamming, riveting, gluing, soldering, welding, etc. In this case, a thermal contact between these components is preferably made.

In the 9a to 9c Examples of LED lighting devices according to the invention ( 10 ) with curved rigid rod-shaped light guides ( 1 ). The means for decoupling ( 4 ) of the LEDs ( 3 ) radiation emitted in the operating state ( 5 ) follow in the drawings the contour of the light guide ( 1 ). But it is also possible that they are in any shape on the light guide ( 1 ) are applied. As based on the 9c can be seen, the means for decoupling ( 4 ) of the radiation also in sections on the light guide ( 1 ) be applied.

The in the 9a to 9c shown embodiments with the bent rigid rod-shaped optical fibers ( 1 ) are preferably used in the position lighting of vehicles, especially in automobiles, trucks and / or trains. In these applications, the lighting equipment ( 10 ) and thus the light guides ( 1 ) preferably integrated in the headlights of the vehicles. The viewer sees in this case through the light guide ( 1 ) and sees the contour of the means for decoupling ( 4 ) in the operating state. So far, such shape profiles have been achieved by attaching a plurality of LEDs. This previous solution has the disadvantage that the probability of failure increases with the number of installed LEDs, as a failed LED has the consequence that the headlight must be replaced. In addition, the LEDs are perceived as individual points of light, which is why the LEDs must not differ greatly in their brightness and their color location. Therefore, the LEDs must be closely selected before their installation, which increases the manufacturing cost. Furthermore, a plurality of LEDs consume more power and produce more waste heat. The LED lighting device according to the invention is equipped with significantly fewer LEDs per headlamp, in particular with a maximum of two per luminous band, which from the light guide ( 1 ) is represented. As a result, the invention contributes to saving electricity and / or fuel.

The embodiments according to the 10a and 10b represent the application of the position lighting of vehicles. 10a schematically shows a headlight of an automobile or a train, in which a lighting device according to the invention ( 10 ) has been integrated. The light guide ( 1 ) can be used in the operating state as daytime running lights. In the application of the power train of a train he can serve as rear position light.

10b schematically represents the tail light of an automobile. Also in these lighting devices were integrated in this example. The light guides ( 1 ) are to be perceived in the operating state as glowing bands. To each of the light guides ( 1 ) can be displayed on one or both sides ( 2 ) LEDs ( 3 ) can be arranged. To the number of LEDs ( 3 ) and thus to reduce the power consumption, it is also possible that in the operating state, light from at least one LED unit by means of flexible fiber optic light guide ( 8th ) to the entry surfaces of the rigid optical fibers ( 1 ) to be led. The typical red color of lighting in rear lights of automobiles can be, for example, by coloring the light guides ( 1 ) and / or through the use of red emitting LEDs ( 3 ) and / or by the introduction of color filters in the beam path or in front of the light guide ( 1 ) and / or by coloring the entrance surfaces ( 2 ) of the light guide ( 1 ) and / or by colored means for decoupling ( 4 ).

11 shows by way of example a particularly preferred field of application of the illumination device according to the invention ( 10 ), namely for illuminating the interior of an aircraft, here a passenger cabin. According to an exemplary embodiment, an LED illumination device ( 10 ) according to 8th installed instead of fluorescent tubes in the cabin. In addition to the already described advantages with respect to insensitivity to vibrations and power savings, the LED lighting device according to the invention has ( 10 ) in this application, the further advantage that it can fulfill a dual function of general and ambient lighting, especially when the LEDs ( 3 ) are executed in the form of LED chips, which make different colors and lighting scenarios possible by color mixing.

The featured LED lighting devices ( 10 ) have the advantage over the prior art that they make the advantages of the LED technology for area lights available. The choice of glass according to the invention makes it possible to provide high color fidelity of the lighting and good energy efficiency. In particular, the LED lighting devices ( 1 ) also be able to be used in environments in which strong vibrations can occur. With a suitable choice of material, they are also flameproof and allow use in environments with high fire protection requirements.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 4733332 [0005]
• DE 102009001170 A1 [0006]

Cited non-patent literature

• ISO 719 [0017]
• DIN 12116 [0017]
• ISO 695 [0017]

Claims (10)

LED lighting device ( 10 ) with at least one rigid rod-shaped light guide ( 1 ), the at least one end face ( 2 ), the at least one LED ( 3 ), and whose outer peripheral surface area has means for decoupling ( 4 ) of radiation ( 5 ), wherein in the operating state that of the at least one LED ( 3 ) emitted radiation ( 5 ) through the end face ( 2 ) in the light guide ( 1 ) and in the light guide ( 1 ) guided radiation from the means for decoupling ( 4 ) of radiation ( 5 ) in the light guide ( 1 ) and passing through the light guide ( 1 ) laterally out of the light guide ( 1 ) is coupled, wherein the optical fiber ( 1 ) consists, at least in the core area, of a multicomponent glass which in total contains at most 50 ppm Fe ²⁺ and / or Fe ³⁺ . LED lighting device ( 10 ) according to the preceding claim, wherein the glass contains (in% by weight based on oxide): SiO ₂ 70-85 B ₂ O ₃ 8-20 Na ₂ O + K ₂ O + Li ₂ O 2-8 Al ₂ O ₃ 0-7 MgO + CaO + BaO + ZnO 0-5 LED lighting device ( 10 ) according to at least one of the preceding claims, wherein the at least one LED ( 3 ) in a housing body ( 30 ) whose wall is used as a heat sink for the LED ( 3 ) and means for holding ( 20 ) of the rigid rod-shaped light guide ( 1 ) or directly with means for holding ( 20 ) of the flexible or rigid rod-shaped optical fiber is connected. LED lighting device ( 10 ) according to claim 3, wherein the means for holding ( 20 ) of the rigid rod-shaped light guide ( 1 ) are formed so that an axial displacement of the rigid rod-shaped optical fiber ( 1 ) is possible. LED lighting device ( 10 ) according to at least one of claims 3 and / or 4, wherein the rigid rod-shaped light guide ( 1 ) with respect to the housing body ( 30 ) is rotatably mounted about its axis. LED lighting device ( 10 ) according to at least one of claims 3 to 5, wherein the housing body ( 30 ) with a mounting body ( 50 ) for fixing the LED illumination device ( 10 ) is connected to other objects and the mounting body ( 50 ) also as a heat sink for the at least one LED ( 3 ) serves. LED lighting device ( 10 ) according to claim 6, wherein the rigid rod-shaped light guide ( 1 ) by means of at least one support structure ( 40 ) with the mounting body ( 50 ), wherein the rigid rod-shaped optical fiber ( 1 ) with means for fixing the light guide ( 41 ) with the support structure ( 40 ) is connected, that a rotation of the optical fiber is prevented about its axis. LED lighting device ( 10 ) according to at least one of the preceding claims, wherein the LED ( 3 ) comprises a chip, in particular an RGB, an RGBA, an RGBW or an RGGB chip, to which a sensor and measures for controlling the color locus and / or the intensity are assigned. Use of the LED lighting device ( 10 ) according to at least one of the preceding claims for the illumination of interiors of vehicles, preferably aircraft cabins and / or aircraft cargo holds or trains or automobiles. Use of the LED lighting device ( 10 ) according to at least one of claims 1 to 8 as a lighting element of vehicles, preferably as daytime running lights and / or position light on the front of automobiles and / or as an element whose headlights, or as an element of the taillight of automobiles.

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