DE102011112285A1 - Optical device for use as e.g. illumination device and for illuminating e.g. road sign, has lenses arranged in small distance to surface of light sources, where one of lenses focuses light in direction and forms light on defined geometry - Google Patents

Abstract

The device has multiple LED light sources whose light emitting surface (11) radiates electromagnetic radiation. Multiple lenses e.g. convex lens (13) and/or shaping lens, are arranged in a beam path of emitted light. One of the lenses focuses light in one direction and forms light on a defined geometry. Lenses are arranged at very small distance to the light emitting surface of the LED light sources. The convex lens is designed as a collimating convex lens and rod-or cylinder lens that lies in the beam path of the LED light sources.

Description

The invention relates to a device for light shaping of a light emitted by an LED light source comprising one or more LED light sources and one or more lenses. The device serves to generate a light of high homogeneity adapted to the illumination of specific surfaces, objects or rooms.

Light-emitting diodes or LEDs can be designed as artificial light source or light source. They can be used in a variety of ways to illuminate surfaces, objects, or rooms, as well as for illumination, d. H. used to create lighting effects for decorative or artistic effects. LEDs typically include a semiconductor electronic device that emits light when flowing through current. The color of the emitted light, thus the wavelength of the electromagnetic radiation of the diode, depends on the semiconductor material as well as the doping. Some LEDs use so-called converter materials, and to set the desired color - for example, the light of a blue LED is converted by means of a converter material into white light.

Under illumination in this context, the optical illumination or illumination of objects, surfaces or spaces to understand, such as the optical illumination of objects - such as in microscopes - or the illumination of paths, aisles or objects such as traffic signs.

The luminous intensity and the luminous efficacy of the LEDs has been significantly increased in recent years, which constantly opens up further fields of application for such light sources. For example, the luminous efficacy could be increased from less than 1 lumen / watt to more than 200 lumen / watt.

If LEDs were initially used, for example, as a display element for status displays, for example in watches or instruments, they are now also used, for example, as bulbs in flashlights. High-intensity LEDs are now also used in the field of exterior vehicle lighting, for example as a daytime running light or tail light. A rather young field of application is the use of LED light sources in the field of street lighting.

The DE 10 2004 056 252 A1 describes, for example, an LED light source with an optical device, wherein the optical device may be a refractive or diffractive optics or a combination thereof. The optical element may also be a fiber optic, in which the light of the light emitting diode is coupled. By means of an adjustable by means of passport pins configuration, the device described is suitable for use as a lighting device for motor vehicles.

To illuminate streets describes the GB 2457971A an optical device comprising a housing having a plurality of LEDs, wherein a plurality of LEDs are grouped and aligned to illuminate a particular area of a street.

WO 10069101 describes an optical device comprising an LED light source and a lens with two different curvatures in the region of the light exit to produce a light beam with an oval or elliptical cross section. The device is used as a backlight for projection displays.

If, on the other hand, it is necessary to use a plurality of light sources, which are to be formed parallel to a homogeneous light, to achieve a required luminous intensity, then this arrangement is unsuitable for this purpose.

The DE 10 2009 015 088 describes a light source with more than one LED emitting UV light. The light source comprises an array of LEDs and an optical component of glass for detecting and merging the emitted light. The emitted light is to be combined by the optical component in order to achieve a very high power density in a target volume or a high luminance in the visible wavelength range of electromagnetic radiation. It therefore comes to an approximately punctiform compression of the light. An approximately homogeneous illumination of an object or a room that is uniform in area can not be made possible hereby, because due to the point-shaped compaction, the power density at the specific location of the illumination decreases from the inside to the outside.

DE 10 2006 039 705 describes a lens attachment for a headlamp, in which an array of LED light sources is equipped with a lens attachment. The lens attachment consists of individual lenses, which are joined together to form a lens package. Furthermore, the describes DE 10 2004 018 424 a lighting device comprising a light source with a lens and is suitable for ellipsoidal headlights.

In the DE 10 2008 048 379 Finally, an LED light source is described with a collimating optics. The aim is to suitably collimate a wide beam angle of an LED light source. It should At the same time a high temperature resistance of the device can be ensured.

By the known devices and methods, light from LED light sources can be focused and concentrated. By bundling this creates a light beam with a high light intensity in the center as well as a strong drop in the outer region of the light beam intensity. An approximately uniform and homogeneous illumination of surfaces or rooms is therefore not guaranteed.

This results in the object of the invention.

The aim of the invention is to achieve a specific shaping of the light. This can z. B. be a homogeneous and nearly uniform illumination of a room, a surface or an object by means of LED light sources. In this case, the illuminated area, which is illuminated by the emitted light from the light source, should be illuminated as homogeneously and uniformly as possible. Furthermore, a certain light distribution and attenuation of the light intensity to the edge of the illuminated surface should be achieved to z. B. to be able to determine certain gradients from the center to the edge.

The aim may also be to achieve certain shapes of light spot, including square, rectangular, polygonal, round or oval shapes of the spot.

In particular, the desired shape of the light spot with predetermined brightness distribution (eg homogeneous and approximately uniform illumination of the area) should also be achieved if several LED light sources are used in parallel, which produce a larger luminous flux (or radiation flux in the non-luminous area). visible wavelength spectrum of electromagnetic radiation) radiate. The aim is therefore also to form light from a plurality of LED light sources in such a way that on the illuminated or illuminated object or on the surfaces of the illuminated or illuminated space, a planar zone with the desired light intensity distribution (eg homogeneous, approx uniform brightness) is generated. It should also be a compact, small design of the LED light source can be achieved.

Surprisingly, this object is achieved by an optical device comprising one or more LED light sources and one or more lenses, according to one of the independent claims. In this case, the one or more lenses perform the functions of bundling and / or collimating a light emitted by the one or more LED light sources as well as forming, wherein an area of predetermined geometric shape is illuminated at a specific distance from the device and the LED is illuminated. Light is thus shaped.

In this case, the design of the optical device can be kept very small particularly advantageous.

Preferred embodiments and further developments of the invention are to be taken from the respective subclaims.

A homogeneous illumination of a surface is understood in the sense of the invention that a certain proportion of an illuminated surface has a preferably identical brightness by an illumination according to the invention and thus no or only a slight difference in brightness. This means that the brightness of each point of a homogeneously illuminated area differs only slightly, or only slightly, from the other points of the homogeneously illuminated area.

Preferably, the minimum and the maximum deviation of the brightness of the points of a homogeneously illuminated surface, starting from the mean value of the brightness of all points in this region, lie in a range of less than ± 15%, preferably less than ± 10% of the radiation density. The brightness can be determined as luminous flux per area.

The invention can form electromagnetic radiation, thus also electromagnetic radiation in the non-visible wavelength spectrum of electromagnetic radiation, for example in the ultraviolet or infrared range. A homogeneity of an irradiated area can therefore also be determined by means of the deviation of the radiation density of an irradiated area in the non-visible wavelength spectrum of electromagnetic radiation.

The following photometric variables have been chosen for the sake of simplicity. However, the invention or the photometric variables are therefore not limited to the visible wavelength spectrum of the electromagnetic radiation.

The proportion of the approximately homogeneously illuminated surface on the total illuminated surface may be at least 60%, preferably at least 70% and particularly preferably more than 75%. Thus, the vast majority of illuminated by the optical device surface is illuminated approximately homogeneously. For other light distributions similar tolerances are to be applied.

The geometric shape of the surface may include a variety of possible shapes, such as circular or rectangular areas, but also oval, star or annular surfaces. This list is not meant to be exhaustive. The optical device may be formed according to a predetermined geometric shape.

The invention thus relates to one or more LED light sources. In such light sources, typically a light-emitting layer of a semiconductor emits light. For the purposes of the invention, an LED light source means any arrangement comprising at least one LED light source which emits light. This arrangement may be formed, for example, for the purpose of illumination or illumination, such as a lamp or reading light, but also for the delivery of signals.

Preferably, however, the LED light source is designed for illuminating or illuminating rooms or areas, for example for illuminating streets or corridors. It can also be used for projectors or vehicle lighting. In the following, the term "illuminated surface" will be used in summary, it being understood that this refers to illuminated or illuminated surfaces, spaces or objects according to the invention.

On the other hand, the optical device relates to at least one lens, preferably two or more lenses. The one or more lenses are preferably arranged such that they are arranged in the beam path after the LED light source and, in the case of a plurality of lenses, are traversed successively by a light emitted by the LED light source. In this case, the lens arranged closest to the LED light source is designed as a converging lens, preferably as a collimating condenser lens. The downstream in the beam path, thus further away from the LED light source lens is preferably formed as a shaping lens.

The converging lens therefore focuses the light emanating from the approximately point-shaped LED light source in the direction of the beam path, whereas the shaping lens brings the light bundled in this way into the desired shape. The shaping lens is preferably designed such that it forms the emitted light of the LED light source corresponding to the surface to be illuminated. Both the condenser lens and the shaping lens can be formed from a single or even from several collection or shaping lenses.

The LED light source and the condenser lens can thus be formed independently of the surface to be illuminated, whereas the shaping lens is selected depending on the geometric shape of the surface to be illuminated.

An LED light source can emit light at a wide angle. The angle to be understood here is the double-sided angular range starting from the central axis of the LED light source. Typically, an LED light source emits light in an angular range of ± 90 °. The proportion of the radiated light power decreases starting from the central axis of the LED light source with increasing angle to the outside from. For example, the largest part of the light output is emitted in an angular range of ± 30 °.

It is advantageous in the context of the invention if the LED light source emits at least 50% of the light output in an angular range of ± 35 ° starting from the central axis. As a result, a particularly high efficiency can be achieved.

In order to achieve a high brightness or illuminance on the illuminated surface, which may be required for illuminating roads, for example, high-density LED light sources are selected. A high luminance of a light source can be achieved by a high luminous intensity of the light source and / or a small light-emitting surface.

LED light sources with a luminance of from about L _v = 15 × 10 ⁶ cd / m ² , preferably from about 20 × 10 ⁶ cd / m ^{2, have} proved to be advantageous. The size of a light-emitting surface may be in a range of less than 5 mm ² , for example, 1 mm ² or less.

If the required luminance can be achieved, preferably LED light sources with a small light-emitting surface can be used. This has the advantage that a plurality of LED light sources can be arranged side by side in a small space and thus in a compact design, a light source, comprising an array (field) of a plurality of individual LED light sources, can be formed.

The condenser lens can be arranged in the beam path of the light after the LED light source. Its task is to bundle as much of the light emitted by the LED light source as possible.

The width of the detected radiation angle of the LED light source is to be chosen as large as possible. The converging lens is preferably arranged in the beam path of the LED light source such that it detects at least one angle range of the LED light source which contains at least 50% of the light quantity, preferably 60%, and more preferably more than 65%.

The associated angle range results from the specifications of the LED light source and can be at an angular range of about ± 45 ° to receive about 50% of the amount of light can.

From the angle range, there is a preferred distance between the LED light source and the condenser lens, since the distance affects the size of the convergent lens. The smaller this distance, the smaller the condenser lens can be formed. Basically, therefore, the smallest possible distance is preferred, which ideally lies at approximately zero. The condenser lens is spaced from the LED light source so that it can receive all of the light beams emitted under the corresponding angular range.

As advantageous in the context of the invention, a distance between the converging lens and the LED light source in a range of 0 to 5 mm, preferably from 0.3 to 2 mm has been found. A circular converging lens may be formed at a distance of about 1 mm from the light-emitting surface having a radius of about 5 mm.

This ensures that a sufficiently large proportion of the emitted light can be conducted to the converging lens and this can be made correspondingly small.

The converging lens is advantageously convex on the side facing away from the LED light source in order to focus the exiting light. In this case, the radius of curvature may be spherical or aspherical. Due to the large emission angle of the LED, the converging lens preferably has an aspherical free-form surface, so that via the configuration of the asphere light of the LED light source can enter the convergent lens up to an emission angle of approximately 60 °. A cost-effective to produce spherical training is also possible. The aspect ratio of the condenser lens, thus the ratio of height and width of the lens, is more than 0.1. Conveniently, an aspect ratio of 0.5 to 1.2 has been found.

By a small distance to the LED light source particularly small converging lenses can be provided, which can capture a large part of the emitted light and very well own due to their small dimensions for LED light sources in the form of LED arrays.

In the case of an LED array, the LED light source can consist of a plurality of individual LED light sources, which can be arranged, for example, along lines or areas. The arrangement of the individual LED light sources of the LED array can preferably correspond to the shape of the surface to be illuminated in order to achieve a particularly high homogeneity of the illumination.

If, for example, a rectangular area is to be illuminated homogeneously and approximately evenly, the LED array can advantageously also be rectangular. If, however, a round, for example, a circular or elliptical surface to illuminate homogeneous, the individual LED light sources of the LED array can also be adequately arranged.

However, it is not a mandatory requirement of the invention to arrange the LED array according to the geometric shape of the illuminated surface. Thus, a light distribution with an oval geometric shape can also be generated with a rectangular LED array. Decisive for the shaping of the light is the formation of the lenses.

In another embodiment, the LED array may comprise semiconductor substrates, each of which may comprise a plurality of light-emitting layers. This allows the device to be particularly compact and designed in a very small space.

In one development of the invention, the LED array can comprise LED light sources which emit electromagnetic radiation in different wavelength ranges. This can cause certain color effects in the illuminated area.

In an LED array, each individual light-emitting surface can be assigned to a collective lens. The converging lens can be designed as a rod lens.

In one development of the invention, the converging lens can be designed such that it can receive and focus light from at least two or more individual LED light sources of an LED array. Here, the convergent lens may preferably be formed as a rod or cylindrical lens, comprising a front side facing the LED light source and a rear side, facing away from the LED light source surface.

In a preferred embodiment, the front surface of the cylindrical lens may have a planar shape, the back surface may have a convex, spherical or aspherical shape. The rear surface may also be formed as a free-form surface, the front surface may also be convex or concave, spherical or aspherical.

Example 1:

A rectangular LED array is formed with a plurality of LEDs each formed with a 1 mm × 1 mm light-emitting area. A rod lens is 0.8 mm apart from an LED at its front, with the lens width being 6 mm. The rod length is chosen so large that the lens protrudes on the other side by about 3 mm beyond the light-emitting surface. The back surface of the rod lens is formed with a convex-spherical contour, where R0 = 1.651 mm and the conical constant is formed with k = -1.014. The type of glass chosen is P-LASF47 or P-SF69, as these glasses have proven to be particularly advantageous for this collimation angle. Furthermore, these glasses are characterized by their high refractive index and their compressibility.

In yet another embodiment, more than one rod or cylinder lens are arranged in the beam path of the emitted light in an LED array. Preferably, the first arranged in the beam path cylindrical lenses are arranged parallel to each other and thus receive light of several individual LED light sources, for example, light of several linearly arranged individual LED light sources can be bundled by a single cylindrical lens. By means of these cylindrical lenses, further cylindrical lenses can advantageously be arranged in parallel in the beam path, whereby these can be arranged rotated by 90 ° relative to the aforementioned cylindrical lenses.

Thus, an emitted light of the LED array successively passes through two levels of cylindrical lenses, which may be arranged approximately in the form of a grid. This arrangement of cylindrical lenses is particularly inexpensive to produce and therefore advantageous in quadrangular, preferably rectangular or trapezoidal LED arrays.

Immediately adjacent to the light-emitting surface of the LED light source and in a region between the LED light source and the converging lens may also be arranged reflectors or reflective surfaces, whereby incident light can be reflected and directed in the direction of the converging lens. As a result, the efficiency of the device can be improved.

The condenser lens is preferably made of a heat resistant material, such as an amorphous material, to ensure high temperature stability because, for example, high power LED light sources typically also have high heat output.

At least the temperature stability of the lenses should exceed that of the LED light source. In particular, a durable temperature resistance of the device according to the invention in a range of T _B = 100 ° C and above can be achieved.

Glasses or glass ceramics have therefore proven to be a suitable material for the condenser lens, such materials having a high refractive index preferably being selected. The refractive index is preferably above 1.5, more preferably above 1.7. As suitable glasses, for example, P-SF69, 2-SF70, P-LASF47 or N-LAF33 have been found.

Subordinated in the beam path of the emitted light after passing through the one or more collecting lenses, the device may comprise at least one further shaping lens. This has the task of shaping the bundled lens emerging bundled light in such a way that at the location of the impact of light on an object a homogeneous and uniform brightness is generated.

In this case, the shaping lens is advantageously arranged such that the largest possible part of the light emerging from the converging lens falls on it. Preferably, therefore, the shaping lens is arranged at a close distance to the converging lens. It has been found that a distance of less than 10 mm, preferably less than 6 mm and more preferably less than 3 mm is advantageous in the context of the invention. As a result, the device according to the invention can be built very compact and realized in a small space.

In a particular embodiment, a reflective sheath is disposed between the outer edge (s) of the converging lenses and the outer edge of the shaping lens so that light incident on that sheath can be reflected from the converging lens and deflected onto the shaping lens. The reflective jacket may for example be part of a surrounding housing. This ensures that almost all of the light exiting the collecting lens (s) reaches the shaping lens. In particular, it can be achieved in this way that at least 90%, preferably at least 95%, of the light can reach the shaping lens.

On the side facing away from the LED light source, the shaping lens may typically have a concave surface. This may be spherical or aspherical. Free-form surfaces on the side facing away from the LED light source, which are selected according to the surface to be illuminated, are also particularly suitable. Under a free form surface is to be understood that the said surface may have different curvatures, which may also extend in different directions. The conical lens facing surface of the shaping lens may have a plane or a concave shape, these embodiments are often convenient, but not mandatory, to form a light beam.

Example 2:

A converging lens comprises an array of rod lenses and as a shaping lens a single, circular or round lens with a plano-concave sphere, whose diameter is 60 mm and whose thickness is 6 mm at R = -60 mm. The glass type selected is an N-BK7. The rod lenses are spaced 1.5 mm from the LEDs, having a width of 10 mm, a length of 20 mm and a thickness of 5 mm at R0 = 1.715, k = -1.744, C4 = -5.301e-04 and C6 = 4,669e-05.

The shaping lens can also be designed as a rod or cylindrical lens. These can have a flat surface on the side facing the condenser lens and a concave, spherical, aspherical or even freeform surface on the opposite side.

By the shaping lens, the bundle of collimated light beams generated by the converging lens is widened such that the light beams which expand in the further beam path illuminate an area in a fixed distance range to the shaping lens approximately homogeneously. The shape or the curvature of this surface of the shaping lens accordingly determines the surface which is illuminated approximately homogeneously in a certain distance range by the device according to the invention. It has been found that an approximately homogeneous brightness of the illuminated surface can be achieved very well if the surface is arranged at a distance of 0.2 to 20 m, preferably 0.5 to 15 m from the device.

If, for example, a rectangular surface is to be illuminated approximately uniformly and homogeneously, then the concave outer surface may have different curvatures, at least two curvatures being perpendicular to one another.

Furthermore, instead of the one shaping lens, a plurality of, for example, two shaping lenses, each having one or more curvatures, can also be used in order to achieve more complex forms of illumination. However, it is also possible to arrange two or more shaping lenses, each having one or more identical or different curvatures, arranged one after the other in the beam path.

Often it is cheaper to produce lenses with only one bend. By arranging two lenses to be successively traversed in the beam path, it is thus possible to dispense with the production of a lens with two curvatures if both said lenses each have only one of the corresponding curvatures and both lenses are rotated by 90 °, for example.

The shaping lens may be formed of glass or glass ceramic. However, since the requirements for heat resistance are lower because of a greater distance from the heat-emitting light source, alternative materials such as plastics can also be used. A use of plastics can be improved by a suitable cooling of the light source and thus by a heat removal from the area of the device.

In principle, the device according to the invention can be used not only for electromagnetic radiation in the visible range but also for electromagnetic radiation in other wavelength ranges, for example in the adjacent wavelength ranges in the ultraviolet or infrared range.

In addition to circular or rectangular surfaces can be homogeneously illuminated by the optical device according to the invention surfaces and other geometric shapes in different distance ranges and irradiated approximately uniformly by means of LED light. This includes, for example, star-shaped or annular lighting of surfaces, objects or rooms.

For example, the optical device can be used to illuminate or illuminate streets, corridors, paths or squares, as well as interiors and internal corridors or paths, to illuminate objects such as traffic signs, pictures, workplaces or tables.

The ability to freely shape the light from LED light sources, thus an approximately uniform illumination of differently shaped objects can be achieved.

The device can also be used to illuminate objects - such as in microscopes.

In a particular embodiment, differently colored LED light sources can be used in parallel, for example in an LED array. In this way, certain areas can be highlighted in color with a uniform illumination of surfaces.

This development is particularly suitable for highlighting danger areas, such as opening areas of gates or doors, in color.

For illuminating objects of art, the color temperature of the illumination can be adjusted by additive color mixing.

The device can also be used to illuminate halls, for example, sports or swimming pools, or even stages.

The optical device can also be used as a reading light.

In a further embodiment, the optical device is used for projectors.

A further field of application is, for example, the vehicle lighting. Here, the device can be used, for example, for homogeneous illumination of parts of the interior, for example the headliner.

Further details of the invention will become apparent from the description of the illustrated embodiments and the appended claims.

The drawings show:

1 a schematic arrangement of an LED light source and a condenser lens,

2 a schematic example of a beam path of light beams in an embodiment of an LED light source according to the invention,

3 FIG. 2: a schematic arrangement of a one-dimensional LED array in cross section, comprising a collimating lens for collimation and a shaping lens for light shaping, FIG.

4 FIG. 2: a schematic arrangement of a two-dimensional LED array comprising cylindrical or cylindrical lenses, FIG.

5 FIG. 2: a schematic arrangement of a rectangular embodiment of an LED array, FIG.

6 FIG. 2: a schematic arrangement of a star-shaped embodiment of an LED array, FIG.

7 FIG. 2: a schematic arrangement of a rectangular embodiment of an LED array with lattice-shaped cylindrical or cylindrical lenses in plan view, FIG.

8th FIG. 2: a schematic example of a beam path of light beams in an embodiment of LED light sources of a one-dimensional LED array, FIG.

9 a circular illuminated area,

10 an example of an area illuminated by an LED array at 5 m distance,

11 a brightness distribution of an illuminated area in a cross-section,

12 : a brightness distribution of an illuminated area in a longitudinal section and

13 : An exemplary arrangement of a positive lens and an LED light source.

Detailed description of preferred embodiments

The photometric quantities mentioned in the description have been chosen for the sake of simplicity and are not limited to the visible wavelength spectrum of the electromagnetic radiation, since the invention relates to the formation of electromagnetic radiation also outside the visible wavelength spectrum. Therefore, z. As the photometric quantity luminous flux and the more general size radiation flux, and the luminance and the radiance.

1 shows schematically the structure of an LED light source with a condenser lens 13 , The LED light source is characterized by a substrate 12 on which a light-emitting surface 11 is arranged. The substrate 12 may be a semiconductor element. The condenser lens is at a small distance from the light-emitting surface 11 arranged such that the central axis of the light-emitting surface extends through the vertex of the curved surface of the converging lens. The converging lens can be rotationally symmetrical. But it can also be designed as a rod lens or cylindrical lens.

The LED light source is on a surrounding housing body 14 arranged. This has a mirroring on the side of the collecting lens associated 16 on. The condenser lens 13 comprises on the side facing away from the LED light source a convex surface. This can be a spherical or aspherical form 15 or even a free-form surface.

In 2 schematically a beam path of light rays is shown. The of the light-emitting surface 11 emitted light rays 21 meet the condenser lens, which they leave bundled by refraction. Showing an emerging light beam 22 ,

In 3 schematically the construction of a one-dimensional LED array with several converging lenses and a shaping lens is shown. The LED array consists of three individual light-emitting layers 11 . 33 . 35 on respective substrates 12 . 32 . 34 , In a further embodiment of the invention, not shown, several light-emitting layers can also be arranged on a common substrate. Each LED light source of the array is a positive lens 13 . 36 . 37 assigned. Due to the achievable small design of the converging lenses they can be arranged very close to each other.

Typically, the converging lenses have straight outer edges so that they abut one another without a gap. The individual lenses can be combined to form a lens package. In a rotationally symmetrical converging lens straight edges can be generated by grinding four sides.

Downstream in the beam path is a shaping lens 39 formed, which receives the light emerging from the condenser lens and scatters. For this purpose, the shaping lens has an optically active surface 38 on. By optically active surface is meant that surface through which the desired refraction, diffraction, reflection and / or scattering takes place. This surface may be concave, convex, spherical or aspherical. Examples of aspherical, active surfaces may be elliptical, cylindrical and / or parabolic surface shapes.

The active surfaces of the at least one shaping lens are to be selected depending on the desired shape of the illumination. As advantageous for a flat, rectangular illumination is about a curvature in two mutually perpendicular directions.

Between the LED array and the shaping lens is advantageously a lateral surface 30 arranged, which may be formed as an inner surface of a housing. Preferably, this lateral surface is mirrored on the side facing the LED light so as to reflect impinging light rays and to guide them to the converging lens.

In a further embodiment, the converging lens is designed as a rod lens or cylindrical lens. 4 shows two such cylindrical lenses 61 . 62 , In this case, the lens is arranged such that it lies in the beam path of a plurality of individual LED light sources. In the illustrated case, each light of a row comprising four individual LED light sources is directed to a respective cylindrical lens. The schematically illustrated LED array 63 thus comprises two rows of four individual LED light sources. The individual LED light sources covered by the lens are incidental through the light-emitting surface 64 and the substrate 65 characterized.

5 schematically shows the structure of a two-dimensional LED array, comprising five rows, each with six individual LED light sources. Schematically are light-emitting layers 11 and the condenser lens 13 shown. In 6 a star-shaped LED array is shown comprising a total of 16 light-emitting layers 11 and accordingly many collecting lenses 13 , The shape of the LED array can be based on the desired shape of the surface to be illuminated.

In 7 an inventive LED array is shown in plan view. LED light sources are in five rows of four individual light-emitting areas 11 summarized. Five designed as a cylindrical lens converging lenses and another four designed as a cylindrical lens collection or shaping lenses are each arranged in parallel and rotated 90 ° to each other, arranged one above the other.

8th shows an example of a beam path through an LED array, comprising four LED light sources in a row, in cross section. From the light-emitting surface 11 Starting from the light rays through the converging lenses 13 bundled and fall on shaping lens 39 , The shaping lens has an active area 81 on, which is responsible for a wide scattering of emerging light rays 82 is trained.

The exiting light rays 82 fall on a surface shown in section 85 , Depending on the curvature of the active surface 81 The shaping lens is irradiated on this area area with different brightness. Thus, the brightness of the illuminated area is different. A central region A is irradiated approximately homogeneously by the refraction of the light rays, whereas an outer region C is not or hardly irradiated. There is also a transition region B, which has a lower homogeneity and a lower brightness than the central, homogeneous region A.

9 shows two possibilities of light shaping. The light shaping 91 shows a broad distribution of light 95 whereas the light shaping 92 a light distribution with a strong spot in the middle 93 shows. Both with the wide light distribution 95 as well as the strong light spot in the middle 93 There is a transition area 96 . 94 , which is characterized by a decreasing brightness. The area of wide light distribution 95 as well as the spot in the middle 95 On the other hand, they are illuminated almost uniformly and homogeneously.

10 shows a possible brightness distribution in an illuminated area in a rectangular shape. As a light source, an LED array with 76 LED light sources can be used, wherein the LED light sources can be arranged in four rows.

As a converging lens, four rod lenses made of the glass P-LASF47 can be used particularly favorably, which can have a spacing of 1.5 mm from the light-emitting surface. A rod lens may have a length of 40 mm and a width of 10 mm. The rod lenses can be produced inexpensively and make it possible to bundle the light of the LED array particularly well.

A rotationally symmetrical shaping lens can be favorably formed from the glass N-BK7 with a diameter of the lens of 60 mm and a thickness of 6 mm and have a plano-concave shape. The distance to the light-emitting surface may be 8 mm. An advantageous embodiment of the shaping lens can be determined by the parameters R = -1.96, K = -1.591, C4 = -2.256e-04 and C6 = -6.386e-06.

101 shows an illuminated area in the size of 6 m × 12 m, which is 5 m away from the device. The radiance of the incoherently irradiated by the LED array surface may be about 68% to 75%, more preferably 69.2%.

102 shows an area of 3 m × 6 m at a distance to the device of also 5 m, wherein the radiance can be about 41% to 48%, particularly preferably 44.5%. In 103 is a 2 m × 9 m large area, also shown at a distance of 5 m to the device. The radiance may be about 22% to 30%, more preferably 26.6%.

In 11 is the distribution of the steel density of the illuminated, rectangular area 101 in a section in the transverse direction, ie in the direction of the shorter extension X, shown, wherein the section extends through the center of the surface. For the half width FWHM the angular range of the device is approximately +/- 13.5 °.

12 shows the distribution of the radiance of the illuminated, rectangular area 101 in a section in the longitudinal direction through the center of the surface, ie in the direction of the greater extent Y. The associated angle range of the half-width FWHM here is approximately +/- 27.5 °.

By means of such an optical device formed, a large area of the rectangular area can be illuminated approximately homogeneously and uniformly, at the same time effecting a smooth transition from the brighter illuminated, near-center area to the surrounding, less brightly illuminated area of the area. A sharp transition from a bright to a less brightly lit area can therefore be avoided.

13 shows a possible arrangement of a condenser lens 131 for condensing the light from serially arranged LED light sources, for the sake of simplicity, only one light-emitting surface 11 and a substrate 12 are drawn. The rear paraxial focal point of the lens lies within the lens. The emitting area 11 the LED is 0.6 mm from the plane surface of the condenser lens 131 spaced and is surprisingly not in the rear paraxial focal point of the lens.

In this way, a very good collimation of the light of the light-emitting surface of the LED by the converging lens 131 be achieved.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102004056252 A1 [0006]
• GB 2457971 A [0007]
• WO 10069101 [0008]
• DE 102009015088 [0010]
• DE 102006039705 [0011]
• DE 102004018424 [0011]
• DE 102008048379 [0012]

Claims (31)

An optical device comprising one or more LED light sources and one or more lenses, wherein Electromagnetic radiation is emitted from a light-emitting surface of one or more LED light sources, - The one or more lenses are arranged in the beam path of the emitted light, A lens concentrating the light in at least one direction, - A lens shapes the light on a defined geometry and - One or more lenses are arranged at a very small distance from the light-emitting surfaces or the light emitting surfaces of the LED light source. Optical device according to the preceding claim 1, characterized in that the light emitted by the LED light source illuminates a surface of predetermined geometrical shape at a predefined distance from the device. Optical device according to the preceding claims, characterized in that the surface of predetermined geometric shape has an approximately equal brightness or a predetermined brightness distribution (+/- 25%). Optical device according to the preceding claims, characterized in that the one or more lenses are designed as collecting and / or as a shaping lens. Optical device according to the preceding claims, characterized in that the emitted light is concentrated and / or collimated in a first step in at least one direction and shaped in a subsequent step. Optical device according to the preceding claims, characterized in that the one or more converging lenses are designed as a collimating condenser lens. Optical device according to the preceding claims, characterized in that the LED light source comprises at least one light-emitting surface, wherein at least 50% of the light power are radiated in an angular range of ± 35 ° from the central axis of the LED light source. Optical device according to the preceding claims, characterized in that the luminance of the LED light source is at least L _v = 10 × 10 ⁶ cd / m ² , preferably at least L _v = 15 × 10 ⁶ cd / m ² and particularly preferably at least L _v = 20 × 10 ⁶ cd / m ² . An optical device according to the preceding claims, characterized in that the condenser lens is spaced from the LED light source such that it receives 50% of the light amount of the light emitted by the LED light source, preferably 60%, and more preferably 65%. Optical device according to the preceding claims, characterized in that the converging lens is convex on the side facing away from the LED light source. Optical device according to the preceding claims, characterized in that the converging lens on the side facing away from the LED light source side has one or more spherical and / or aspheric and / or free-form curves. Optical device according to the preceding claims, characterized in that the converging lens is formed as a rod or cylindrical lens, wherein the rod or cylindrical lens is located in the beam path of one or more than a single LED light source. Optical device according to the preceding claims, characterized in that more than one rod or cylindrical lens are arranged parallel to each other. Optical device according to the preceding claims, characterized in that more than one rod or cylindrical lens are arranged in the beam path of the light emitted by the LED light source. Optical device according to the preceding claims, characterized in that the converging lens is formed from a temperature-stable material made of glass or glass ceramic with a refractive index of at least n _d > = 1.5, preferably n _d > = 1.7. Optical device according to the preceding claims, characterized in that the LED light source comprises a plurality of individual LED light sources, which are arranged in the form of an LED array. Optical device according to the preceding claims, characterized in that each LED light source of the LED array is associated with exactly one converging lens. Optical device according to the preceding claims, characterized in that each collecting lens is associated with a plurality of individual LED light sources of an LED array. Optical device according to the preceding claims, characterized in that the concentrated light strikes almost completely on at least one lens disposed in the beam path. Optical device according to claim 18, characterized in that the downstream lens is designed as a shaping lens. Optical device according to Claims 18 and 19, characterized in that the shaping lens has a concave surface on the side facing away from the LED light source. Optical device according to the preceding claims, characterized in that the shaping lens on the side facing away from the LED light source side has one or more spherical and / or aspherical and / or free-form curves. Optical device according to the preceding claims, characterized in that the shaping lens has different curvatures in two mutually perpendicular directions. Optical device according to the preceding claims, characterized in that at least one further shaping lens is arranged in the beam path after the shaping lens. Optical device according to the preceding claims, characterized in that a permanent temperature resistance at an operating temperature in a range of at least T _B = 100 ° C is given. Use of an optical device according to the preceding claims, for illuminating or illuminating surfaces and / or objects, in particular for illuminating traffic signs, signs, pictures, workplaces, tables, buildings or structures. Use of an optical device according to the preceding claims 1 to 25 for illuminating or illuminating rooms, corridors, halls or stages. Use of an optical device according to the preceding claims 1 to 25 as lighting for paths, aisles, streets or squares. Use of an optical device according to the preceding claims 1 to 25 as a reading light. Use of an optical device according to the preceding claims 1 to 25 as a lighting device of projectors. Use of an optical device according to the preceding claims 1 to 25 as a lighting device in and on vehicles.

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