Lighting device with light distributing body

Abstract

The invention relates to a lighting device, in particular for lighting an interior, said lighting device having: a lighting means (3); and a light distributing body (1) having a light coupling surface (11) and a translucent light exit region (12). The light distributing body (1) has a substantially spherical shape and is designed to dispense, in a directed manner, a first portion of the light which is emitted by the lighting means (3) and which is introduced into the light distributing body (1) via the light coupling surface (11), and to diffuse a second portion of the introduced light by means of the light distributing body (1) such that the light exits in a diffused manner substantially via the entire light exit region (12) of the light distributing body (1). The light distributing body (1) is solid and the light coupling surface (11) is the interface between a recess (6) in the light distributing body (1) and the light distributing body (1).

Description

[0001] Lighting device with light distribution body Description

[0002] The present invention relates to a lighting device with a light distribution body according to the subject matter of claim 1.

[0003] Lighting devices with different beam characteristics are known, each suitable for lighting purposes in different applications. For example, lighting devices with diffuse beam characteristics are known. Such lighting devices are suitable for evenly illuminating a large area of ​​a room. On the other hand, lighting devices designed to emit directed light, such as spotlights or floodlights, are known. Such lighting devices can be used to specifically illuminate a limited area of ​​a room.

[0004] In many cases, it is desirable to use both beam characteristics simultaneously to illuminate a room, for example, in workspaces with a workstation. There, it is desirable to illuminate the room evenly while simultaneously providing increased illumination for the workstation. Likewise, to create a pleasant atmosphere, it is often desirable to combine diffuse lighting of the room with directional lighting of specific areas.

[0005] Various luminaires are known in the prior art that combine different illuminants with different radiation characteristics to simultaneously generate diffuse and directed light. For example, DE 20 2016 102 638 Ui discloses a hybrid luminaire that has at least one LED illuminant for emitting a directed luminous flux and at least one planar OLED illuminant for emitting a diffuse luminous flux.

[0006] Since the hybrid luminaire requires separate light sources to provide the different beam characteristics, the space required and the manufacturing effort are increased. Against this background, the object of the present invention is to provide a lighting device suitable for emitting directed and diffused light. Furthermore, the present invention aims to provide a lighting device that, despite the possibility of generating directed and diffused light, is characterized by a structurally simple and compact, space-saving design.

[0007] The problem is solved by a lighting arrangement having the features of claim 1. Advantageous further developments emerge from the subclaims.

[0008] The object is achieved in particular by a lighting device, in particular for illuminating an interior space, comprising a light source, a light distribution body with a light coupling surface and a translucent light exit region. The light distribution body is essentially spherical. The light distribution body is designed to direct a first part of the light emitted by the light source and introduced into the light distribution body via the light coupling surface, and to scatter a second part of the introduced light by means of the light distribution body, such that the light exits diffusely essentially over the entire light exit region of the light distribution body. The light distribution body is solid, wherein the light coupling surface is formed at an interface between a recess in the light distribution body and the light distribution body.The recess comprises a first part which has the shape of a spherical element, a cone or a flattened area, wherein the shape of the first part can be either positive or negative.

[0009] A key concept of the invention is to provide a light distribution body and to configure it such that coupled light emitted by a (single) illuminant is partially diffused and partially directed from the light distribution body. This achieves a structurally simple and space-saving design of a lighting device with two emission characteristics, since only one illuminant and one (relatively compact) light distribution body are required. The geometric design of the recess (on which the light coupling surface is formed) serves to specifically influence the emission characteristics of the light distribution body.

[0010] The light distribution body fulfills a dual function. A (first) portion of the light coupled into the light distribution body is guided and preferably directed inside the light distribution body such that this portion of the light exits the light distribution body in a directed manner. Preferably, the directed portion of the coupled light exits via a partial area of ​​the light exit area. A (second) portion of the light coupled into the light distribution body is scattered or distributed by the light distribution body such that this portion of the coupled light is emitted diffusely over substantially the entire light exit area, preferably over the entire light exit area. The diffusely emitted light is preferably scattered both upon exiting the surface of the light distribution body, which forms the light exit area, and during internal reflections inside the light distribution body.The internal reflections also distribute the light in the light distribution body.

[0011] The light distribution body thus generates a diffuse emission pattern by scattering one (first) portion of the coupled-in light and a directed emission pattern by directing the other (second) portion of the coupled-in light. According to the invention, the light distribution body is thus designed to emit light coupled in via the light coupling surface with an emission pattern that represents a superposition of a diffuse emission pattern and a directed emission pattern. Advantageously, no separate illuminants or optical elements for modifying the emission pattern are required to provide this emission pattern.

[0012] The lighting device according to the invention has a radiation characteristic that represents a superposition of a diffuse and a directed radiation characteristic. Thus, with the lighting device according to the invention, a room, in particular an interior, can be uniformly illuminated with a single light source, while simultaneously illuminating a limited area of ​​the room with the directed light component.

[0013] In the context of the present invention, diffuse light emission or emission characteristic is understood to mean a spatial emission pattern that has a substantially constant intensity over a large solid angle range, preferably over a solid angle range of 2 n sr (steradians) or more. In contrast, directed light emission or emission characteristic refers to a spatial emission pattern in which the emission is limited to a small solid angle range of less than 2 n sr, preferably less than 1 sr. Directed light emission is therefore not limited to collimated light emission, but also includes a conical emission pattern with a small emission angle of preferably 45°. 0 or less.

[0014] To ensure the light distribution function inside the light distribution body, it is further preferred that the light distribution body be made of a transparent material, preferably glass or a transparent plastic. According to the invention, the light distribution body is solid (i.e., without cavities) and preferably consists essentially entirely of the transparent material.

[0015] With such a light distribution body, the directed portion of the emitted light can be implemented particularly easily. A light distribution body formed by a solid, substantially spherical body made of a transparent material is particularly preferred. In this configuration, a portion of the light introduced into the light distribution body is focused by the substantially spherical light distribution body. This portion of the coupled-in light exits the light distribution body in a directed manner via a region of the light exit surface of the light distribution body that is opposite the light coupling surface. Thus, the directed portion of the emission of the coupled-in light can be implemented particularly easily using a geometrically compact and easy-to-manufacture light distribution body.It is preferred that the substantially spherical light distribution body has a diameter of more than 5 cm, particularly preferably between 5 cm and 50 cm.

[0016] A substantially spherical body is one whose shape deviates only slightly from a spherical shape. For example, ellipsoids in which the difference in the length of the semi-axes is significantly smaller than the length of the shortest semi-axis (preferably, no difference in the length of the semi-axes is more than 10% of the length of the shortest semi-axis) are to be understood as substantially spherical in the context of this description. A positive or negative characteristic is to be understood in each case as meaning that the corresponding geometric figure (the spherical element or the truncated cone) is curved inwards, i.e., is part of the recess (positive characteristic of the shape), or is curved outwards, thus forming part of the light distribution body (negative characteristic of the shape).

[0017] Since the recess receives the largest portion of a light wave front emitted by the light distribution body before it enters the light distribution body, the geometric nature of the first part of the recess is of key importance for the beam path inside the light distribution body, since the light coupling surface, which is formed at the interface between the recess and the light distribution body, refracts the coupled-in light rays. Due to the fact that the first part of the recess - and thus the light coupling surface - is opposite the area of ​​the light distribution body from which the directed radiation occurs, the geometric design of the recess - and thus of the light coupling surface - has a major influence on the proportion of coupled-in radiation that is emitted in a directed manner.

[0018] If the connecting line between the center of the light distribution body and a central point of the first part of the first recess is defined as the optical axis, for example, selecting the shape of the first part as a spherical element with a positive characteristic results in incident rays being refracted away from the optical axis. This leads to a decrease in the proportion of directed radiation relative to the proportion of diffusely emitted radiation. Conversely, designing the shape of the first part as a spherical element with a negative characteristic results in the incident rays being refracted toward the optical axis, thereby increasing the proportion of directed radiation.

[0019] A comparable, albeit quantitatively different, effect occurs if a cone (with positive or negative characteristics) is chosen as the shape of the first part instead of the spherical element.

[0020] In a preferred embodiment, the recess further comprises a second part, which is shaft-shaped or substantially cylindrical, wherein the first part is arranged at an end of the second part facing away from the surface of the light distribution body. In other words, it is preferred that the second part of the recess, which is shaft-shaped or substantially cylindrical, extends from the surface of the light distribution body into its interior, and the first part of the recess is arranged at the inner end of the second part. A second part of the light coupling surface is formed at the interface between the second part of the recess and the light distribution body (i.e., the lateral surface of the shaft-shaped or substantially cylindrical second part of the recess).In this case, the light coupling surface is composed of two parts: a first part formed at the interface between the first part of the recess and the light distribution body, and a second part formed at the interface between the second part of the recess and the light distribution body. It is particularly preferred that a longitudinal axis of the second part of the recess extends substantially along a radial direction of the light distribution body.

[0021] A shaft-shaped recess is understood to mean a recess which extends essentially straight along a longitudinal direction, whereby the cross-section is not necessarily constant.

[0022] The advantage resulting from the design of the recess with the second part is that the radiation emitted by the illuminant is initially “guided” in the interior of the light distribution body, partly by reflection on the lateral surface of the second part of the recess, before the radiation passes through the part of the light coupling surface formed on the first part of the recess.

[0023] At the same time, by appropriately selecting the depth of the second part of the recess, it is possible to control which portion of the radiation originally emitted by the illuminant is already emitted into the light distribution body before the remaining portion of the emitted radiation enters the first part via the part of the light coupling surface formed on the first part of the recess.

[0024] If the second part is designed to be longer, a larger proportion of the incident light rays, whose propagation direction is not parallel to the extension direction of the second part, are coupled into the light distribution body via the part of the light coupling surface which consists of the interface between the second part and the light distribution body, thereby increasing the proportion of diffusely emitted radiation.

[0025] According to a further preferred embodiment, the surface of the light coupling surface is completely and / or partially roughened and / or matte.

[0026] By specifically roughening or matting the light coupling surface, the proportion of diffusely emitted radiation can be increased in a simple and effective manner, as reflection at the light coupling surface is reduced.

[0027] According to a further aspect of the invention, the light distribution body has a reflector element and / or scattering centers for modifying the ratio of directed and diffuse radiation of the light distribution body. The reflector element is preferably formed by a partially or fully reflective layer arranged inside the light distribution body or on the light coupling surface, or within the recess, which fully or partially reflects incident radiation. By reflecting incident light rays at the reflector element, the proportion of directed radiation can be further reduced or specifically adjusted by partial reflection. Depending on the angular position of the reflector element, it is also possible to adjust which proportion of the incident light rays enters the light distribution body at which angle, whereby the directed radiation characteristics can be further influenced.

[0028] By incorporating scattering centers into the light distribution body, the proportion of diffusely emitted radiation can be further increased. The scattering centers can be introduced into the solid light distribution body, for example, by irradiating it with a highly focused laser beam.

[0029] In a further preferred embodiment, the recess (associated with the light coupling surface) in the light distribution body has a recess depth and a recess diameter, wherein the recess diameter corresponds to the maximum diameter of the recess at an end of the recess facing the illuminant, wherein the recess diameter and the recess depth are each less than or equal to the radius of the light distribution body, and wherein the extent of the recess in directions which are orthogonal to the direction of the recess depth is never greater than the recess diameter.

[0030] The recess depth is composed of the depth of the first part of the recess and, if present, the depth of the second part of the recess. The recess depth is composed of the depth of the first part and, if present, the depth of the second part. The depth here is the maximum extent of the recess along a direction parallel to the optical axis. In the case of a recess with a second, shaft-shaped or cylindrical part, the depth runs along the longitudinal axis of the second part of the recess.

[0031] By adjusting or selecting the ratio between the recess diameter and the recess depth, the radiation characteristics of the light distribution body can be further influenced. Larger recess diameters generally result in a larger proportion of diffusely emitted radiation, whereas smaller recess diameters generally result in a larger proportion of directed radiation. As already explained above with regard to the depth of the second element, a larger recess depth also results in a higher proportion of diffusely emitted radiation, and a smaller recess depth results in a higher proportion of directed radiation.

[0032] It is further preferred that the recess depth is greater than, preferably (at least) twice as large as, the recess diameter (D).

[0033] Also preferred are embodiments in which the recess diameter is less than a quarter of the radius of the light distribution body, preferably less than a fifth, more preferably less than a tenth.

[0034] By choosing a small recess diameter, excessive hollowing of the solid light distribution body is avoided and a sufficiently large volume is created within the light distribution body for light propagation and distribution. This allows the beam pattern to be advantageously manipulated by the design of the light distribution body.

[0035] According to a preferred embodiment of the invention, the lighting device has a light guide designed to guide light emitted by the illuminant to the light coupling surface of the light distribution body. As a result, the illuminant can be arranged at a distance from the light distribution body. This can be advantageous from a design perspective. In addition, the distance between the illuminant and the light distribution body can be specifically adjusted by selecting the length of the light guide accordingly. This can contribute to modifying the beam angle of the directed light component. As illustrated in several embodiments described herein, according to the present invention, light emitted by the illuminant can be guided to the light coupling surface of the light distribution body with or without a light guide.Any optical element that can transport light within the light guide between an input and output surface of the light guide can be used as a light guide. For example, an optical waveguide can be used as a light guide. Elongated elements, such as cylindrical or prism-shaped elements made of a transparent material such as glass or a transparent plastic, can also be used as light guides. The light emitted by the light source is coupled in via a base surface and coupled out via the axially distant base surface.

[0036] According to a further preferred embodiment of the invention, the light exit region of the light distribution body is formed by a frosted surface. Specifically, the light exit region is formed by a frosted surface on a surface of the light distribution body. This makes it particularly easy to provide diffuse light exit across the entire light exit region. The frosting of the light exit region can be achieved in the usual way by roughening the surface, for example, by etching or sandblasting.

[0037] In a preferred embodiment, the light distribution body is formed by a solid, substantially spherical body made of a transparent material, the surface of which is frosted with the exception of the light coupling surface. Due to the spherical shape, a (first) portion of the coupled-in light is bundled and exits in a directed manner via a surface region of the light distribution body or a portion of the light exit region opposite the light coupling surface. Another (second) portion of the coupled-in light exits diffusely at the frosted surface of the light distribution body (i.e., at the light exit region) and / or is diffusely reflected at the frosted surface inside the light distribution body and subsequently diffusely emitted via the frosted surface.

[0038] In some examples, for example, only a part of the (spherical) surface of the

[0039] The light distribution body may be frosted (or roughened), e.g., as described herein. The frosted and / or non-frosted areas may be configured such that, for example, the light exits primarily through the frosted areas. For example, no light may exit through the non-frosted areas.

[0040] However, it is also possible that the diffusely emitted light emerges (mainly) from the frosted areas of the surface of the light distribution body, and (partially) also from the non-frosted areas.

[0041] In embodiments with a (substantially) completely frosted surface of the light distribution body, for example (as described herein), the second part of the introduced light is scattered by means of the frosted surface of the light distribution body, so that the light exits diffusely over substantially the entire (frosted) light exit area of ​​the light distribution body.

[0042] In embodiments in which the surface of the light distribution body comprises frosted and non-frosted parts, the second part of the introduced light can be scattered by the light distribution body, in particular the frosted part of the surface of the light distribution body. This allows the light to exit diffusely over essentially the entire (frosted) light exit area of ​​the light distribution body, for example, at the frosted and / or partially also the non-frosted parts of the surface.

[0043] Particularly in embodiments with a non-frosted (e.g., polished) surface of the light distribution body, a portion of the introduced light can be scattered by scattering centers inside the light distribution body (as described herein), so that the light essentially exits diffusely (also) via the non-frosted surface. In examples with a completely non-frosted (e.g., polished) surface of the light distribution body, a portion of the light can also exit via the entire (non-frosted) light exit area of ​​the light distribution body. However, examples with a (completely) non-frosted surface are also conceivable.

[0044] This makes it possible to create a lighting device that provides a particularly advantageous and aesthetically pleasing combination of diffuse and directed radiation characteristics using only a single light source, that is particularly simple and cost-effective to manufacture, and that has a particularly compact design. Surprisingly, it has been found that using a solid, (essentially) spherical light distribution body made of a transparent material with a frosted surface as the light exit area results in a lighting device in which the intensity of the light component diffusely emitted by the light distribution body has a satisfactorily high intensity across the entire light exit area, which is suitable for uniform and atmospheric lighting, while the directed component of the emitted light is bright enough to illuminate a limited area of ​​space in a spot-like manner.

[0045] It is further preferred that the light coupling surface be formed by a smoothly ground or polished region at the interface between the recess of the light distribution body and the light distribution body. This facilitates the coupling of light into the light distribution body.

[0046] The light source is preferably formed by one or more LEDs and is further preferably designed as an LED cluster or LED RGB module. This makes it possible to provide a bright, energy-efficient, and compact light source with low manufacturing costs. The lighting device preferably has exactly one light source, which is formed by a (single) LED or an LED cluster or an LED module. If an LED RGB module is used as the light source, the color of the light emitted by the lighting device can be variably adjusted. Due to internal reflections and scattering, the light distribution body causes a mixture of the light colors emitted by the individual LEDs of the LED RGB module. This results in light emission with a homogeneous color.

[0047] In a (further) preferred embodiment, the light distribution body has areas on its surface with a reflective coating designed to partially or completely reflect light that propagates inside the light distribution body and strikes the reflective coating. By providing a reflective coating in certain areas, the radiation characteristics of the light distribution body can be further modified in a targeted manner. The radiation of directed and / or diffuse light can, for example, be limited to certain solid angle ranges or specifically reduced in certain areas.When using a light distribution body with a convex (especially spherical) shape with a frosted surface, surface areas can be excluded from the light exit area by applying a reflective coating with total reflection, since no light can escape from the light distribution body in these areas.

[0048] According to a (further) preferred embodiment, the lighting device comprises a holder in which the light distribution body is mounted for rotation about its center point. This allows the user to easily adjust the direction of the directed light by rotating the light distribution body in the holder. A substantially spherical light distribution body is particularly preferred in this embodiment, as this can be mounted for rotation about its center point in a structurally simple manner.

[0049] It is further preferred that the lighting device has a dome that partially or completely encloses the light distribution body. This allows the surface of the light distribution body to be protected from contamination and damage. This protection is particularly advantageous for light distribution bodies with a frosted surface, since contamination of the frosted surface can influence the diffusion effect and lead to altered transmission behavior.

[0050] According to a preferred development, the dome has surface areas with different transmittances, which are designed to modify the radiation characteristics of the light distribution body. Preferably, at least one surface area has a partially reflective and / or a fully reflective coating. According to this development, the radiation characteristics of the lighting device can be modified by appropriately designing the dome without having to modify the light distribution body. This allows suitable radiation characteristics of the lighting device to be realized depending on the application. Furthermore, an aesthetically pleasing design of the lighting device can be realized.

[0051] The invention is described below with regard to further details, features, and advantages, which are explained in more detail with reference to the figures. The described features and feature combinations, as shown below in the figures of the drawing and described with reference to the drawing, are applicable not only in the respective specified combination, but also in other combinations without thereby departing from the scope of the invention.

[0052] Here we show:

[0053] Fig. 1 is an exploded perspective view of a lighting device with a light distribution body according to an embodiment of the present invention;

[0054] Fig. 2 is an exploded view of the lighting device from Fig. 1 in section;

[0055] Fig. 3 is a sectional view of the lighting device from Fig. 1 in the assembled state;

[0056] Fig. 3a is an illustration of a first embodiment with a light distribution body, wherein the frosted surface forming the light exit region of the light distribution body comprises only a part of the surface of the light distribution body;

[0057] Fig. 3b is an illustration of a second embodiment with a light distribution body, wherein the frosted surface forming the light exit region of the light distribution body comprises only a part of the surface of the light distribution body;

[0058] Fig. 3c an illustration of a third embodiment with a

[0059] Light distribution body, wherein the frosted surface forming the light exit area of ​​the light distribution body comprises only a part of the surface of the light distribution body;

[0060] Fig. 3d is an illustration of a fourth embodiment with a light distribution body, wherein the frosted surface forming the light exit region of the light distribution body comprises only a part of the surface of the light distribution body;

[0061] Fig. e is a sectional view of the lighting device from Fig. 1 in the assembled state with a flat light coupling surface;

[0062] Fig. 3f is a sectional view of the lighting device from Fig. 1 in the assembled state with a convex light coupling surface;

[0063] Fig. 3g is a sectional view of the lighting device from Fig. 1 in the assembled state with a convex light coupling surface and a circumferential notch;

[0064] Fig. 3h is an illustration of a fourth embodiment with the light distribution body from Fig. 3g and without light guide;

[0065] Fig. 3i is an illustration of a fifth embodiment with the light distribution body with a flat light coupling surface and a circumferential notch;

[0066] Fig. 4 is a schematic illustration of the radiation characteristic that can be achieved with the lighting device according to the embodiment shown in Figs. 1 to 3;

[0067] Fig. 5 is an illustration of a variant of the embodiment shown in Fig. 4 with a schematic representation of the achievable radiation characteristic;

[0068] Fig. 6 is an illustration of an embodiment in which the recess consists only of the first part; Fig. 7 is an illustration of an embodiment with a recess consisting of a first and a second part;

[0069] Fig. 8 shows a further embodiment, wherein the first part consists of a flattening;

[0070] Fig. 9 shows an embodiment in which the first part consists of a negative spherical segment;

[0071] Fig. io shows an embodiment in which the first part consists of a negative truncated cone;

[0072] Fig. 11 shows an embodiment with a reflector element on the light coupling surface.

[0073] Fig. 12 & 13 Embodiments with different arrangements of scattering centers in the light distribution body.

[0074] Fig. 14 an arrangement with a reflector element in the light distribution body;

[0075] Fig. 15 is a graph qualitatively illustrating the angle dependence of the radiation characteristic that can be produced with the lighting devices shown in Figs. 4 and 5;

[0076] Fig. 16 is a schematic sectional view of a lighting device with a light distribution body according to a further preferred embodiment of the present invention with modified radiation characteristics;

[0077] Fig. 17 shows a schematic sectional view of a lighting device with a light distribution body according to another preferred embodiment of the present invention with modified radiation characteristics; Figs. 18 and 19 show a schematic sectional view of a lighting device with a light distribution body according to another preferred embodiment of the present invention with a holder for the light distribution body;

[0078] Fig. 18a & 19a a schematic sectional view of a lighting device according to Fig. 18 & 19, wherein the lighting device does not comprise a light guide;

[0079] Fig. 20 is a schematic sectional view of a lighting device with a light distribution body according to another preferred embodiment of the present invention with a dome;

[0080] Fig. 21 is an illustration of a variant of the embodiment shown in Fig. 20.

[0081] The figures are merely schematic in nature and serve solely to facilitate understanding of the invention. Identical or similar elements are provided with the same reference numerals in the description of the embodiments.

[0082] Fig. 1 shows a perspective exploded view of a lighting device according to a preferred embodiment of the present invention. The lighting device comprises a light distribution body 1, a light guide 2, and a light source 3 as its main components.

[0083] The illuminant 3 is preferably formed by an LED or an LED unit comprising several LEDs, for example, an LED cluster or an LED module, but is not limited thereto. The illuminant 3 is designed to emit light in the direction of the light guide 2 and the adjoining light distribution body 1.

[0084] The light guide 2 is formed by an elongated, essentially cylindrical body made of a transparent material, the longitudinal axis of which extends along a central axis of the lighting device. The central axis is shown as a dash-dotted line in the exploded view of Fig. 1. At each axial end, the light guide 2 has a light input surface 21 and a light output surface 22. The light input surface 21 and the light output surface 22 are preferably surfaces with a high degree of transmission, which can be achieved, for example, by appropriate polishing and / or applying a suitable coating. The outer surface of the light guide 2 can be provided with a suitable reflective coating to improve light transmission between the illuminant 3 and the light distribution body 1. Alternatively, the outer surface of the light guide 2 can be provided with an opaque cover.It is also possible that the lateral surface of the light guide 2 has no special modification and is formed by an untreated or not specially treated surface.

[0085] The light guide 2 serves to guide light emitted by the illuminant 3 into the light distribution body 1. To couple the light into the light distribution body 1, the latter has a light coupling surface 11. In the assembled state, the light guide 2 is attached to the light coupling surface 11 with the light output surface 22. This can be seen in Figs. 2 and 3, which show a schematic sectional view of the lighting device from Fig. 1. The illuminant 3 is attached to the light coupling surface 21 of the light guide. The light output surface 22 of the light guide 2 is attached to the light coupling surface 11 of the light distribution body 1. Thus, light emitted by the illuminant 3 is coupled into the light guide 2 via the light coupling surface 21. The light is then guided in the light guide 2 to the light coupling surface 11 of the light distribution body 1.The light is finally coupled into the light distribution body 1 from the light output surface 22 of the light guide 2 via the light input surface 11 of the light distribution body 1.

[0086] The light distribution body 1 in the embodiment shown in Figs. 1 to 3 has a convex shape. Specifically, the light distribution body 1 shown there is essentially spherical. The shape of the light distribution body 1 deviates from a spherical shape only at the light coupling surface 11. The light coupling surface 11 in the embodiment shown in Figs. 1 to 3 is formed in a recess in the light distribution body 1.

[0087] The light distribution body 1 is solid and is made of a transparent material such as glass or transparent plastic. Glass is the preferred material for the light distribution body i. To emit the coupled light, the light distribution body i has a light exit area 12 on its surface. In the substantially spherical light distribution body shown in Figs. 1 to 3,

[0088] Light distribution body 1, the light exit area 12 is formed essentially by the entire surface of the light distribution body 1 with the exception of the light coupling surface 11.

[0089] The light exit area 12 of the light distribution body shown in Figs. 1 to 3 is formed by a frosted or satin-finished surface, i.e., a finely roughened surface on which light is diffusely scattered within the interior of the light distribution body 1 and through which light diffusely exits from the interior of the light distribution body 1. Such a surface can be obtained, for example, by sandblasting or etching in a light distribution body 1 made of glass.

[0090] 3a-3d show various embodiments according to Fig. 3 with a light distribution body 1, wherein the frosted surface forming the light exit region 12 of the light distribution body 1 comprises only a part of the surface of the light distribution body 1: In detail, various partial regions of the surface of the light distribution body 1 can be frosted, e.g. as described herein: In the examples of Figs. 3a-3c, the frosted portion is represented by the square-patterned area, and its proportion increases from Fig. 3a to Fig. 3c. The frosted portion of the surface of the light distribution body 1 can, on the one hand, comprise, for example, at least a first predetermined portion of the surface of the light distribution body 1 and / or be, for example, 25% or more, 50% or more, or 75% or more. The frosted portion of the surface of the light distribution body 1 can, on the other hand, e.g.comprise a maximum of a second predetermined proportion of the surface of the light distribution body 1 and / or be, for example, 90% or less, 75% or less, or 60% or less. While in Figs. 3a-3c the partial area of ​​the surface of the light distribution body 1 substantially opposite the light coupling surface 11 is matt, in the example of Fig. 3d the partial area of ​​the surface of the light distribution body 1 adjacent to the light coupling surface 11 is matt. Essentially a similarly large partial area of ​​the surface of the light distribution body 1 is matt in the example of Figs. 3b and 3d. By means of arrangements as shown by way of example in Fig. 3d, for example, the proportion of directed light emitted relative to diffusely emitted light can be increased.

[0091] Preferably, the frosted portion of the surface is substantially opposite the light entry surface 11, e.g., rotationally symmetrical (as shown, for example, in Figs. 3a-3d). Furthermore, in other embodiments, the frosted region can be oriented arbitrarily relative to the light coupling surface 11, e.g., non-rotationally symmetrical.

[0092] The transition between the one or more frosted portions of the surface of the light distribution body 1 and the one or more non-frosted portions of the surface of the light distribution body 1 can, for example, be direct (within the scope of manufacturing accuracy) or comprise a smooth transition, e.g., with a width of 1 mm to 10 mm, preferably 2 mm to 5 mm. The borders of the portions of the surface of the light distribution body 1 can run essentially on circular paths (as shown in Fig. 3a-3d) or have any other, e.g., angular and / or curved, paths.

[0093] 3e-3h show designs of the light coupling surface 11 which differ from the embodiment shown in Fig. 3: In detail, Fig. 3e shows a sectional view of the lighting device with a flat light coupling surface 11, Fig. 3f shows a sectional view of the lighting device with a convex light coupling surface 11 and Figs. 3g and 3h show a sectional view of the lighting device with a convex light coupling surface 11 and a circumferential notch (in this example represented by a rectangular notch which runs in a circle around the light coupling surface 11). The notch, as shown in Fig. 3g, for example, can be designed to attach the light distribution body 1 to a further device, e.g. the light guide 2 and / or a socket running around the notch. The socket and the light distribution body can, for example, be designed such that they can be detachably connected to one another by means of a screw connection.For example, the cylindrical extension formed by the notch can be provided with an external thread for this purpose. The socket can, for example, be connected to further elements of a lighting device, e.g. the light source. Fig. 3h and 3i show illustrations of an embodiment with the light distribution body 1 without a light guide 2. In principle, all of the embodiments described here can be designed with (as shown, for example, in Fig. 3e-3g) or without a light guide 2 (as shown, for example, in Fig. 3h and 3i). Fig. 3h shows an illustration of a fourth embodiment with the light distribution body 1 from Fig. 3g and without a light guide 2. Fig. 3i shows an illustration of a fifth embodiment with the light distribution body 1 with a flat light coupling surface 11 and a circumferential notch.

[0094] With the lighting device according to the embodiment shown in Figs. 1 to 3, a radiation pattern can be generated that includes both a directed component and a diffuse component. This is explained below with reference to Figs. 4, 5, and 15.

[0095] Fig. 4 is a schematic illustration of the radiation characteristic that can be achieved with the lighting device according to Figs. 1 to 3. Fig. 5 shows a variation of the embodiment shown in Figs. 1 to 3 without light guide 2, with which a radiation characteristic with a directed and diffuse component can also be obtained.

[0096] First, the radiation characteristics of the lighting device with the configuration shown in Fig. 4 will be explained. Light emitted by the light source 3 is guided via the light guide 2 into the light distribution body 1. Exemplary beam paths through the light guide 2 are schematically represented by the arrows in the light guide 2. The light source 3 does not emit collimated light, but rather radiates light over a certain angular range. This can also result in reflections on the inner wall of the light guide 2. Light coupled from the light guide 2 into the light distribution body 1 therefore enters the light distribution body 1 at different angles.

[0097] Since the light distribution body 1 is formed solidly from a transparent material, a first portion of the coupled light, which enters the light distribution body 1 at a sufficiently small angle relative to the center axis of the lighting device (shown in dash-dotted lines), is partially collimated or directed. This (first) portion of the coupled light exits the light distribution body 1 in a directed manner in a region of the light exit area 12 opposite the light coupling surface 11. This is illustrated in Fig. 4 by the solid arrows at the upper end of the light distribution body 1, which represent the directed portion of the emitted light.

[0098] A second portion of the coupled-in light—namely, essentially the light that exits non-directionally in the region of the light exit area 12 opposite the light coupling surface 11—exits diffusely from the light distribution body across the entire light exit area 12. As conceptually illustrated in Fig. 4 by the small dotted arrows inside the light distribution body 1, a portion of the light that strikes the frosted surface from the inside is diffusely reflected back into the interior of the light distribution body 1. As a result, the second portion of the coupled-in light is evenly distributed across the light distribution body 1 and exits diffusely across essentially the entire light exit area 12 of the light distribution body 1. This is illustrated in Fig. 4 by the dotted arrows on the surface of the light distribution body 1, which represent the diffuse portion of the emitted light.Due to the frosted surface, additional scattering occurs when the light exits the light exit area 12.

[0099] In the embodiment shown in Fig. 5, no light guide 2 is present. Here, the light emitted by the illuminant 3 is coupled directly into the light distribution body 1 via the light coupling surface 11. However, the generation of directed and diffused light occurs essentially analogously to the embodiment shown in Fig. 4 and described above. Again, a (first) part of the coupled-in light is directed by the collimating effect of the solid light distribution body 1 and exits in a directed manner via a part of the light exit area 12 that lies opposite the light coupling surface 11. A (second) part of the coupled-in light (essentially the part that exits the light distribution body 1 in a non-directed manner) is distributed over the light distribution body 1 by internal reflections at the frosted surface and exits diffusely through the frosted surface essentially over the entire light exit area 12.

[0100] The radiation characteristic achievable with the lighting device according to the present invention, and in particular with the lighting devices shown in Figs. 4 and 5, is formed from the superposition of a diffuse and a directed component. This is schematically illustrated in the graph in Fig. 15. The x-axis represents the polar angle θ of a spherical coordinate system with its origin at the center of the light distribution body 1. A value of 0° denotes the direction along the center axis of the lighting device away from the light coupling surface 11. The y-axis represents the intensity of the light emitted at the respective angle θ, without a specific unit.

[0101] The (first) portion of the emitted light, which forms the directed portion, exits through a region of the light exit area 12 opposite the light coupling surface 11. This directed light exit is represented in Fig. 15 as an increased emission intensity at small values ​​of 0. The (second) portion of the emitted light, which forms the diffuse portion, is diffusely emitted essentially over the entire light exit area 12 and manifests itself as a constant background in the graph in Fig. 15.

[0102] Overall, the lighting device according to the invention creates a radiation pattern with a directed component for the targeted illumination of a limited spatial area and a diffuse component for the uniform illumination of a large spatial area. In other words, the lighting device according to the invention is suitable for creating spot lighting with a very soft spot that transitions into a diffuse illumination component that is emitted across almost the entire solid angle. Surprisingly, the intensity of the diffuse component is so high that the diffuse component enables atmospheric, uniform illumination. At the same time, the intensity of the directed component is so high that the directed component creates a significantly brighter, soft spot that can be used to specifically illuminate a limited spatial area.

[0103] The lighting device according to the invention emits both directed and diffused light from the light distribution body 1, requiring only a single illuminant 3 for this purpose. Furthermore, only one compact optical element is required to generate the radiation characteristic with a directed and a diffuse component. The light distribution body 1 generates from the coupled light both a directed component of emitted light over a limited solid angle range and a diffuse component of emitted light, which is emitted over a very large solid angle range.

[0104] By simple modifications of the light distribution body 1, the radiation characteristics described with reference to Figs. 4, 5 and 15 can be suitably modified depending on the lighting requirements. If, for example, it is desired that no light is emitted over a certain solid angle range, corresponding areas of the surface of the light distribution body 1 can be excluded from the light exit region 12 by applying a cover or a reflective coating with total reflection. The use of a reflective coating is preferred here, as it can improve the light yield. Light that is reflected inside the light distribution body 1 by the reflective coating can still exit the light distribution body 1 via the light exit region 12.

[0105] Fig. 6 shows an embodiment of a light distribution body 1 according to the invention with a light exit region 12. In Figures 4 to 14, the dash-dotted line indicates a rotational symmetry axis of the light distribution body 1. In the embodiment according to Fig. 6, the recess 6, at whose interface with the light distribution body 1 the light coupling surface 11 is formed, consists only of a first part 61. The first part 61 is formed here by a positive spherical segment. Due to this configuration of the first part 61, the incident light is refracted in such a way that previously parallel light rays diverge upon entering the light distribution body 1. This reduces the proportion of directed light emitted. The recess depth T and the recess diameter D of the recess 6 are shown in Fig.6 are designated by the corresponding reference numerals and result from the dimensions of the recess 6 (which in the present embodiment consists only of the first part 61).

[0106] Fig. 7 shows a further exemplary embodiment of a light distribution body 1 according to the invention with a light exit region 12. In this exemplary embodiment, the recess 6, the interface of which with the light distribution body 1 forms the light coupling surface 11, consists of a first part 61 and a second part 62. The recess depth T is composed of the depth of the first part 61 and the second part 62. The recess diameter D results from the dimensions of the second part 62. The first part 61 is also formed here by a positive spherical segment. As a result of this, and because light rays that do not run exactly parallel to the optical axis can already exit into the light distribution body 1 via the part of the light coupling surface 11 that borders the second part 62, the proportion of diffusely emitted radiation in the radiation characteristic increases again.In the exemplary embodiment shown here, the recess depth T corresponds almost to the radius of the light distribution body 1. The recess diameter D shown is significantly smaller than the radius of the light distribution body 1. In the embodiment shown, the recess diameter D corresponds to just under a third of the radius of the light distribution body 1. Fig. 8 shows a further exemplary embodiment of the light distribution body 1 with a light coupling surface 11 and a light exit region 12, in which the first part 61 is formed by a flattened area and thus has essentially no depth. In this case, this recess depth T is essentially defined by the second part 62 of the recess 6. By designing the first part 61 as a flattened area, light rays running parallel to the optical axis are not refracted when entering the light distribution body 1, which increases the proportion of radiation emitted in a directed manner.As can be seen here, the recess diameter D is essentially half the size of the recess depth T. The recess diameter D corresponds to just under a third of the radius of the light distribution body.

[0107] Fig. 9 shows a further embodiment of the light distribution body 1 with a light exit region 12. In this embodiment, the recess 6, the interface of which with the light distribution body 1 forms the light coupling surface 11, consists of a first part 61 and a second part 62. The recess depth T thus results from the depth of the first part 61 and the second part 62 in combination. The recess diameter D thus results from the dimensions of the second part 62. The embodiment shown is largely analogous to that in Fig. 7, but here the first part 61 is formed by a negative spherical segment. As a result, the part of the light coupling surface 11 which is formed at the interface between the light distribution body 1 and the first part 61 of the recess has a collimating effect on the incident light rays, thereby increasing the proportion of the radiation emitted in a directed manner.The first part 61 of the recess 6 is formed by the area adjacent to the negatively shaped spherical segment.

[0108] Fig. 10 shows a further embodiment of the light distribution body i with a light exit region 12. In this embodiment, the recess 6, whose interface with the light distribution body i forms the light coupling surface n, consists of a first part 61 and a second part 62. The embodiment shown is largely analogous to those in Figs. 7 to 9, but here the first part 61 is formed by a negative cone segment. The effect of the light coupling surface 11 is therefore similar to that described with reference to Fig. 9. Thus, in this embodiment, too, the proportion of directed radiation is increased.

[0109] Fig. 11 is a further modification of the embodiment shown in Fig. 10. As an additional feature, a reflector element 14 is attached to the light coupling surface. The reflector element 14 reflects incident rays back sideways, reducing the proportion of directed radiation. This proportion can be adjusted by varying the transmittance of the reflector element 14.

[0110] Fig. 12 shows a modification of the embodiment shown in Fig. 6, in which scattering centers 15 are introduced into the light distribution body in a semicircular pattern to influence the radiation characteristics over a wide angular range. Fig. 13 shows a further embodiment in which a different distribution of the scattering centers 15 is selected. The scattering centers 15 cause a diffuse distribution of the light in the light distribution body 1 and increase the proportion of diffusely emitted radiation.

[0111] In particular in embodiments in which scattering centers 15 are located in the light distribution body, the surface of the light distribution body 1 can be completely or at least partially unmatted.

[0112] Fig. 14 shows an embodiment 6, in which a reflector element 14 is incorporated into the body of the light distribution body 1 to reduce the proportion of directed light emitted. Depending on the desired intensity of the directed radiation, the reflector element 14 can be partially reflective or fully reflective.

[0113] Fig. 16 and Fig. 17 show two schematic views of a lighting device with a correspondingly modified light distribution body 1. The light distribution bodies 1 in Fig. 16 and Fig. 17 are provided in some areas with a reflective coating 13. In the area of ​​the reflective coating 13, no light exits the light distribution body 1, so that the areas with the reflective coating 13 do not form part of the light exit area 12.

[0114] In the configuration shown in Fig. 16, a region of the surface of the light distribution body opposite the light coupling surface 11 is provided with a reflective coating 13. With this configuration, the proportion of directed light is significantly suppressed. The remaining light exit area 12 emits essentially diffuse light, some of which has been reflected by the reflective coating 13 inside the light distribution body.

[0115] In the configuration shown in Fig. 17, a reflective coating 13 is applied over an annular region of the surface of the light distribution body 1. With this configuration, a superposition of directed and diffused light is emitted in a region of the light exit region 12 opposite the light coupling surface 11. Another part of the light exit region 12 borders the light coupling surface 11 and serves to emit diffuse light. Between the two parts of the light exit region 12, the reflective coating 13 forms a region in which no light is emitted.

[0116] Instead of a reflective coating 13, a tinted area on the surface of the light distribution body 1 or a coating with reduced transmittance can also be provided, so that the intensity of the emitted light in these areas can be reduced and adjusted. The exemplary embodiments shown in Figs. 16 and 17 with modified emission characteristics can also be combined with the configuration of the lighting device without light guide 2 shown in Fig. 5. The portion of the light coupled into the light distribution body 1 that is emitted in a directionally manner is emitted via a surface area opposite the light coupling surface n when using an essentially spherical light distribution body i. In order to be able to adjust the direction of the directed light portion, the lighting device can be mounted movably.It is particularly preferred to mount the lighting device such that the light distribution body 1 is mounted so as to be rotatable about its center point. With such a mounting, the direction of the directed light can be changed by rotating the light distribution body 1 without the light distribution body 1 changing its absolute position.

[0117] This is shown in Fig. 18 and Fig. 19. According to this exemplary embodiment, the lighting device is mounted in a schematically shown holder 4 such that the light distribution body 1 can rotate about its center point. In the position shown in Fig. 18, the directed light component emitted by the lighting device is emitted vertically upwards. If the light distribution body 1 is rotated in the holder, the direction of the directed light changes, as shown in Fig. 19. The position of the light distribution body 1, however, remains unchanged. This makes it possible to create a lighting device with a small space requirement which has a radiation characteristic with a diffuse component and a directed component, wherein the radiation direction of the directed component is adjustable.

[0118] The configuration with holder shown in Fig. 18 and Fig. 19 can be combined both with the configuration without light guide 2 shown in Fig. 5 and with a light distribution body 1 with modified radiation characteristics according to the embodiments described with reference to Fig. 16 and Fig. 17.

[0119] Fig. 18a & 19a show an analogous schematic sectional view of a lighting device, wherein the lighting device does not comprise a light guide. This serves to clarify that even embodiments with a rotatably mounted light distribution body can be designed with or without a light guide 2. In order to protect the light distribution body i and in particular its frosted surface from contamination and damage, the lighting device can have a (transparent) dome that at least partially encloses the light distribution body i. Such a configuration is shown in Fig. 20. In addition to the light distribution body 1, the light guide 2 and the illuminant 3, the lighting device has a dome 5 that surrounds the light distribution body 1.To improve the overall aesthetic appearance, it is preferred in this embodiment if the outer surface of the light guide 2 is provided with an opaque cover or coating (not shown). This reduces the visibility of the light guide 2, creating the optical impression that the light distribution body 1 is floating inside the dome 5.

[0120] In order to modify the radiation characteristics of the lighting device according to Fig. 20, the dome 5 can be provided in certain areas with coatings having a reduced transmittance. This is shown schematically in Fig. 21. The dome 5 has a first (partially) reflective coating 51 in an upper area and a second (partially) reflective coating 52 in an annular area around the upper area. The transmittances of the coatings 51, 52 differ from one another. Coatings with a transmittance of 0 can be used, i.e., fully reflective coatings, or partially reflective coatings with a transmittance between 0 and 1. Likewise, partial tinting of the dome 5 can be used to modify the radiation characteristics of the lighting device.

[0121] If, in the exemplary embodiment shown in Fig. 21, the first coating 51 is designed as a fully reflective coating and the second coating 51 as a partially reflective coating, the directed portion of the light emitted by the light distribution body 1 is essentially completely reflected by the first coating 51. A portion diffusely emitted by the light distribution body 1 emerges through the region of the second coating 52, the intensity of which is reduced by the second coating 52. This creates a glare-free lighting device with diffuse radiation characteristics over a limited spatial area. The configuration of the coatings 51, 52 shown in Fig. 21 is purely exemplary.It will be apparent to those skilled in the art that any combination and arrangement of coatings and / or tinted areas on the dome 5 can be used to achieve a desired modification of the radiation characteristics of the lighting device. The dome 5 can also be configured to be removable and replaceable. This allows the radiation characteristics of the lighting device to be modified by simply replacing the dome 5 with one with a different coating and / or tint configuration, without requiring any modification or alteration of the light distribution body 1 or the illuminant 3.

[0122] It is obvious to the person skilled in the art that the embodiments shown in Figs. 20 and 21 with the dome 5 can be combined with the other described embodiments of the light distribution body 1.

[0123] List of reference symbols:

[0124] 1 light distribution body

[0125] 1 iLight coupling surface

[0126] 12 Light exit area

[0127] 13 Reflective coating

[0128] 14 Reflector element

[0129] 15 scattering centers

[0130] 2 light guides

[0131] 21 (second) light coupling surface

[0132] 22 Light output surface

[0133] 3 bulbs

[0134] 4 Bracket

[0135] 5 Dome

[0136] 51 first (partially) reflective coating

[0137] 52 second (partially) reflective coating

[0138] 6 Recess

[0139] 61 first part of the recess

[0140] 62 second part of the recess T recess depth

[0141] D Recess diameter

Claims

Claims Lighting device, in particular for illuminating an interior, comprising: a lighting means (3); a light distribution body (1) with a light coupling surface (11) and a translucent light exit region (12); wherein the light distribution body (1) is substantially spherical and is designed to direct a first part of the light emitted by the lighting means (3) and introduced into the light distribution body (1) via the light coupling surface (11), and to scatter a second part of the introduced light by means of the light distribution body (1), so that the light exits diffusely substantially over the entire light exit region (12) of the light distribution body (1), wherein the light distribution body (1) is solid, and wherein the light coupling surface (11) is the interface between a recess (6) of the light distribution body (1) and the light distribution body (1).Lighting device according to claim 1, wherein the recess (6) has a first part (61), which preferably has the shape of a spherical element, a cone, or a flattened area, wherein the shape can be either positive or negative. Lighting device according to claim 1 or 2, wherein the recess (6) comprises a second part (62), which is shaft-shaped or substantially cylindrical, wherein the first part (61) is arranged at an end of the second part facing away from the lighting means (3). Lighting device according to one of the preceding claims, wherein the surface of the light coupling surface (11) is completely and / or partially roughened and / or matte. Lighting device according to one of the preceding claims, comprising. a reflector element (14) for modifying the ratio of directed and diffuse radiation of the light distribution body (1), wherein the reflector element (14) is formed by a partially or fully reflective layer arranged in the interior of the light distribution body (1) or on the light coupling surface (11); and / or Scattering centers (15) for modifying the ratio of directed and diffuse radiation of the light distribution body (1), wherein the scattering centers (15) are formed in the interior of the light distribution body (1). Lighting device according to one of the preceding claims, wherein the recess (6) in the light distribution body (1) has a recess depth (T) and a recess diameter (D), wherein the recess diameter (D) corresponds to the maximum diameter of the recess (6) at an end of the recess (6) facing the illuminant, wherein the recess diameter (D) and the recess depth (T) are each less than or equal to the radius of the light distribution body. Lighting device according to one of the preceding claims, wherein the recess depth (T) is greater than, preferably twice as large as, the recess diameter (D).Lighting device according to one of the preceding claims, wherein the recess diameter (D) is less than one-third of the radius of the light distribution body (1), preferably less than one-quarter, more preferably less than one-fifth, more preferably less than one-tenth. Lighting device according to one of the preceding claims, comprising a light guide (2) designed to guide light emitted by the illuminant (3) to the light coupling surface (11) of the light distribution body (1).

10. Lighting device according to one of the preceding claims, wherein the light exit region (12) of the light distribution body (1) is formed by a matt surface.

11. Lighting device according to one of the preceding claims, wherein the light coupling surface (11) is formed by a smoothly ground or polished area on the surface of the light distribution body (1).

12. Lighting device according to one of the preceding claims, wherein the lighting means (3) is formed by one or more LEDs and is preferably designed as an LED cluster or LED RGB module.

13. Lighting device according to one of the preceding claims, wherein the light distribution body (1) has on its surface regions with a reflective coating (13) which is designed to partially or completely reflect light which propagates in the interior of the light distribution body (1) and strikes the reflective coating (13).

14. Lighting device according to one of the preceding claims, comprising a holder (4) in which the light distribution body (1) is mounted so as to be rotatable about its center point.

15. Lighting device according to one of the preceding claims, comprising a dome (5) which encloses the light distribution body (1), wherein the dome (5) preferably has surface areas (51, 52) with different transmittances, which preferably have partially reflective coatings and are designed to modify the radiation characteristic of the light distribution body (1).

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