WO2016113234A1

WO2016113234A1 - A lighting device for use for example in outdoor lighting applications

Info

Publication number: WO2016113234A1
Application number: PCT/EP2016/050420
Authority: WO
Inventors: Michel Cornelis Josephus Marie Vissenberg; Anna Wilhelmina Maria Wondergem-De Best; Antonius Petrus Marinus Dingemans; Robertus Johannes Maria Mathilde SNIJKERS; Liesbet Hillechina WIND
Original assignee: Philips Lighting Holding B.V.
Priority date: 2015-01-16
Filing date: 2016-01-12
Publication date: 2016-07-21

Abstract

A lighting device (100) is disclosed, comprising a sphere lens (110). A lighting module (120) comprising at least one light-emitting element (125) is arranged with respect to the sphere lens (110) so as allow light emitted from the at least one light-emitting element (125) to be coupled into the sphere lens (110) via a light in-coupling surface portion (111) of the sphere lens (110). The lighting module (120) is configured in relation to the sphere lens (110) so as to provide for a selected arrangement of the at least one light-emitting element (125) relatively to the center of the sphere lens (110), for attaining a selected beam shape and direction of light coupled out from the sphere lens (110). A light-guiding region (140) is delimited at least by a light-redirection surface (142) and the light in-coupling surface portion (111). The light-guiding region (140) at least in part encloses the at least one light-emitting element (125) so as to guide light emitted by the at least one light-emitting element (125) towards the light in-coupling surface portion (111).

Description

A lighting device for use for example in outdoor lighting applications

TECHNICAL FIELD

The present invention generally relates to the field of lighting equipment and devices. Specifically, the present invention relates to a lighting device including a sphere lens for focusing light emitted by at least one lighting module. The lighting device is suitable for use for example in outdoor lighting applications, such as in illumination of roads or streets. The lighting device is however expected to be advantageous or suitable in other applications as well, for example in shelf lighting applications or so called wall washing applications, or in principle any lighting application in which there is required or desired to illuminate a relatively large surface from a point relatively close to the illuminated surface.

BACKGROUND

The use of light-emitting diodes (LEDs) for illumination purposes continues to attract attention. Compared to incandescent lamps, fluorescent lamps, neon tube lamps, etc., LEDs provide numerous advantages such as a longer operational life, reduced power consumption, an increased efficiency related to the ratio between light energy and heat energy, etc. In outdoor lighting applications, e.g. in illumination of roads and/or streets, the intensity distribution of the light illuminating the road or street may be subject to relatively strict requirements in order to attain a desired or required quality of illumination of the road or street. Quality of illumination of a road or a street may be characterized by one or more of aspects such as the average road or street luminance (to an observer), uniformity in luminance, surround ratio, or the so called threshold increment (a measure of glare) or another measure of glare. For example, it may be desired or required to attain two intensity peaks of the light, i.e. relatively high intensities of light within two relatively small regions, with the two intensity peaks exhibiting relatively sharp intensity cut-offs or decays along the direction of road or street. This may be desired or required in order to ensure a uniform road or street illumination for example when there is a relatively large distance between the light sources illuminating the road or street, and in order to at the same time to maintain a relatively low glare. One example of lighting architecture that is used in outdoor LED lighting is a light source based on a printed circuit board (PCB) having an array of LEDs arranged thereon, where each LED in the array of LEDs has a corresponding free-shape lens, e.g. a so called 'peanut' lens, for creating a required or desired intensity distribution of light. The light source may be arranged on top of a pole for illuminating the road or street from above. However, the illumination scenes in outdoor lighting applications such as in illumination of roads and/or streets may vary, and thus the requirements on the intensity distribution of the light illuminating the road or street may vary between different illumination scenes. For example, each combination of road or street width (or the number of lanes), spacing between poles, height of poles, etc., may require a different lighting intensity profile. In such a case, a relatively large number of specific free-shape lenses may be required in order to accommodate for varying requirements on the intensity distribution of the light illuminating the road or street. Also, if a change in type of LED in the light sources would be desired or required, a change in the type and/or configuration of the free-shape lenses may likewise be required. This is due to that the free-shape lens is often specifically adapted to the type and/or configuration of the corresponding LED. Because of the cost of a lens injection mould, a change in the type and/or configuration of the free-shape lens may be relatively expensive. A way to modify the light intensity profile without changing the free- shape lens itself is to change the position of the LED with respect to the free-shape lens. However, when using the commonly used lighting architectures, this may lead to that the output beam shape may vary in an unpredictable way.

SUMMARY

A relatively wide range of (in some cases very) specific light intensity profiles may be needed in different illumination scenes in outdoor lighting applications such as in illumination of roads and/or streets. These specific light intensity profiles may be created by designing a specific free-shape lens for creating each specific light intensity profile.

However, the optical elements or free-shape lenses which are often employed in commonly used lighting architectures for outdoor lighting are usually specifically designed to create a given light intensity profile, and often lack the fiexibility to be used for creating a wide range of light intensity profiles. The light intensity profile may be tuned by changing the LED position with respect to the free-shape lens. However, the currently used free-shape lenses are often designed for attaining a very specific light profile, and are often limited in respect of capability or even possibility of varying the lighting intensity profile. Also, when employing the commonly used lighting architectures, changing the LED position with respect to the free-shape lens may lead to unwanted lighting artifacts such as unpredictable variation in the output beam shape.

In view of the above, a concern of the present invention is to provide a lighting device which facilitates or even enables flexibility in creating specific light intensity profiles of the output beam.

A further concern of the present invention is to provide a lighting device having an optical element that focuses light, e.g. onto a road or a street, which lighting device facilitates or even enables flexibility in creating specific light intensity profiles of the output beam without or with less need for modifying or replacing the optical element in order to create specific light intensity profiles of the output beam.

To address at least one of these concerns and other concerns, a lighting device in accordance with the independent claim is provided. Preferred embodiments are defined by the dependent claims.

According to a first aspect, there is provided a lighting device comprising a sphere lens for focusing light. The lighting device comprises at least one lighting module configured to emit light. The lighting module comprises at least one light-emitting element arranged with respect to the sphere lens so as to allow light emitted from the at least one light-emitting element to be coupled into the sphere lens via a light in-coupling surface portion of an outer surface of the sphere lens. The at least one lighting module is configured in relation to the sphere lens so as to provide for a selected arrangement of the at least one light-emitting element relatively to the center of the sphere lens for attaining a selected beam shape and direction of light coupled out from the sphere lens. The lighting device comprises a light-guiding region delimited at least by a light-redirection surface of a light-redirection element and the light in-coupling surface portion. The light-guiding region at least in part encloses the at least one light-emitting element so as to guide light emitted by the at least one light-emitting element towards the light in-coupling surface portion.

By the use of a sphere lens for focusing light, and by the at least one lighting module being configured in relation to the light in-coupling surface portion so as to provide for a selected arrangement of the at least one light-emitting element relatively to the (center of the) sphere lens, for attaining a selected beam shape and direction of light coupled out from the sphere lens, in principle any intensity pattern or distribution of light output from the lighting device may be attained. A sphere lens may focus light impinging on the sphere lens in principle from any direction, into any direction, with a focal distance F = R · n / [2(n-l)], where R is a radius of the sphere lens, and n is the refractive index of the material the sphere lens is made of. For n = 1.5, the focal distance is F = 1.5R, i.e. light from a light source at a distance 1.5R from the sphere lens is focused into a parallel or substantially parallel light beam. For example in outdoor applications such as in illumination of roads and/or streets, the sphere lens can be used to focus light onto the road or street in such a way as to conform with a requirement on the intensity distribution of the light illuminating the road or street.

In the context of the present application, by a sphere lens it is meant a lens having a spherical or substantially spherical form. The sphere lens may be made of in principle any light-transmissive or clear material, including for example one or more of glass, polymethylmethacrylate (PMMA), polycarbonate and silicone.

One sphere lens is preferably used in conjunction with one lighting module for focusing light emitted by the lighting module. A configuration in which one lighting module or light source is used with more than one sphere lens (i.e. where several sphere lenses are used to focus light emitted by the same lighting module or light source) may not be useful, since moving a light-emitting element with respect to a first sphere lens may cause an unwanted optical effect with respect to a second sphere lens.

The selected arrangement of the at least one light-emitting element relatively to the sphere lens may at least in part determine the shape and orientation on any intensity peak(s) of the light output from the lighting device, i.e. a relatively high intensity of light within a relatively small region or regions. For example in outdoor applications such as in illumination of roads and/or streets, the selected arrangement of the at least one light-emitting element relatively to the sphere lens may be such that any such intensity peaks may exhibit relatively sharp intensity cut-offs or decays along the direction of road or street.

For example, the lighting module, and/or the at least one light-emitting element, may be arranged relatively to the (center of the) sphere lens such that each of the at least one light-emitting element is arranged at a radial distance from the center of the sphere lens which is larger than the focal distance F of the sphere lens. Possibly, each of the at least one light-emitting element may be arranged at a radial distance from the center of the sphere lens which is equal to or larger than 1.IF, or within an interval, for example between about 1.1F and about 1.2F. Preferably, the light-emitting element that should produce the largest intensity peak in the output light is positioned the closest to the focal position but still outside or beyond the focal position (e.g. just outside an imaginary sphere of radius 1. IF with a center coinciding with the center of the sphere lens). Thereby, occurrence of too sharp images of the light source on the illuminated surface (e.g. on a road or street) may be avoided or reduced. If the at least one light-emitting element is arranged at a radial distance from the center of the sphere lens which is too large, e.g. more than about 1.2F, the peak intensity of the output light may be reduced too much. According to an example, the entire lighting module may be arranged outside an imaginary sphere of radius F with a center coinciding with the center of the sphere lens.

Since a (re-)configuration of the light source (or lighting module) in a lighting device in general is easier to carry out in a relatively late stage or pre-stage of the

manufacturing process of lighting devices, as compared to (re-)configuration of the optical element used for focusing light, the lighting device according to the first aspect may allow for a relatively high flexibility in design thereof so as to conform to a desired or required intensity pattern or distribution of light output from the lighting device (e.g., as desired or required by a user's particular application). Also, conformance to a desired or required intensity pattern or distribution of light output from the lighting device may be less expensive compared to using other lighting architectures, since the cost of a lens injection mould to create a new type and/or configuration of a free-shape lens may be relatively high.

By the light-guiding region, which at least in part encloses the at least one light-emitting element, light emitted by the at least one light-emitting element can be guided toward the sphere lens in order to be in-coupled into the sphere lens, via the in-coupling surface portion. According to embodiments, the light-guiding region may be considered as a light mixing region, or cavity. Light that is redirected e.g. by the light-redirection surface of the light-redirection element may have a lower intensity compared to light emitted by the at least one light-emitting element and not having impinged on a light-redirection surface. Such redirected light can be used to 'fill up' the intensity distribution of light output from the lighting device, outside any intensity peaks, such as mentioned above. The shape and/or size of the light-guiding region may at least in part determine the intensity distribution of light output from the lighting device outside any intensity peaks, while the selected arrangement of the at least one light-emitting element relatively to the sphere lens may at least in part determine the shape and orientation on any intensity peak(s) of the light output from the lighting device, such as mentioned above. In general, a relatively large light-guiding region may produce a broader intensity distribution of light output from the lighting device compared to a smaller light-guiding region.

The light-redirection element may for example comprise a reflective light- scattering element, a diffractive element, a refractive element, a diffusively reflective element, and/or a specularly reflective element. The light-redirection element is not limited to having a particular shape, and it may in principle have any shape. The light-guiding region may for example include or be constituted by open void(s), filled with any gas, such as air, or substantially vacuum. The light-guiding region may have specular or diffuse inner walls or surfaces. According to another example, the light-guiding region may include or be constituted by a solid material. The light-guiding region may for example include a light guide, which in the context of the present application should be understood as a structure arranged to enable propagation of light coupled into it, or convey or guide light coupled into it, for example along a direction in which the light guide extends. Light may for example be guided or conveyed within the light guide by means of undergoing multiple reflections within the light guide, such as, for example, by means of multiple reflections at an interface between the light guide and its exterior, via so called total internal reflection (TIR). The light guide may comprise a material through which light can propagate. The material may at least in part include a transparent material, allowing light to pass through the material without being scattered. The light guide may include one or more materials selected for example from the group including PMMA (sometimes referred to as acrylic glass), polycarbonate, glass, silicone and/or silicone rubber.

The relative positioning of the at least one light-emitting element and the (center of the) sphere lens, e.g. the relative positioning of the light source position(s) (i.e. the point(s) from which light is emitted) and the (center of the) sphere lens, may determine the orientation of the light which is coupled out from the sphere lens. In case there are several light-emitting elements in the lighting module, the positioning of the at least one light- emitting element in the lighting device may be varied by individually controlling the light output from the light-emitting elements.

For example, the lighting module may comprise a plurality of light-emitting elements. Each light-emitting element may be individually controllable with respect to emission of light for attaining the selected beam shape and direction of light coupled out from the sphere lens. For example in case the light-emitting elements include or are constituted by LEDs, the LEDs may be driven at different currents, where the current distribution is based on the desired or required light intensity profile of the output beam or beam shape and direction of light coupled out from the sphere lens. However, all LEDs may be driven at substantially the same current. According to another example, at least two subsets of the plurality of light-emitting elements are individually controllable with respect to emission of light for attaining the selected beam shape and direction of light coupled out from the sphere lens. The subsets may for example be constituted by or include 'strings' of light-emitting elements, e.g. sets of light-emitting elements arranged in a straight or curved line. Each subset, or cluster, of light-emitting elements can include two or more light- emitting elements.

According to another example, the lighting module may comprise a plurality of light-emitting elements. The lighting module may comprise a plurality of allowed positions in which light-emitting elements can be arranged, where the number of allowed positions exceeds the number of light-emitting elements. The selected arrangement of the at least one light-emitting element relatively to the sphere lens may be attainable by the plurality of light-emitting elements being arranged in selected ones of some of the allowed positions. A different way to describe such a configuration is that the lighting module (e.g., including a printed circuit board, PCB) may have multiple sites, in only some of which light- emitting elements (e.g., including LEDs) may be arranged, and where the arrangement of the light-emitting elements in the sites is selected based on the desired or required light intensity profile of the output beam or beam shape and direction of light coupled out from the sphere lens.

According to another example, the lighting module may comprise an organic

LED (OLED) which is easily configurable in shape, e.g. by using a patterned cathode, a pixelated OLED that is matrix-addressable, or an OLED that can be cut to a certain size or shape.

According to another example, the lighting module may be selected from a set of lighting modules, each of which has a plurality of light-emitting elements arranged in different patterns (e.g., so called L2 boards). The lighting module which is selected has its plurality of light-emitting elements arranged in a pattern which allows for or facilitates attaining the desired or required light intensity profile of the output beam or beam shape and direction of light coupled out from the sphere lens.

The at least one lighting module, or the at least one light-emitting element, may be arranged in relation to the light in-coupling surface portion so as to enable light emitted by the at least one lighting module to be substantially directly coupled, or substantially indirectly coupled, into the light in-coupling surface portion.

According to one example, the at least one lighting module, or the at least one light-emitting element, may be arranged in relation to the light in-coupling surface portion so as to enable light emitted by the at least one lighting module to be substantially indirectly coupled into the light in-coupling surface portion, with only a relatively small fraction of the light emitted by the at least one lighting module being directly coupled into the light in- coupling surface portion. Thus, light may be able to reach the sphere lens substantially indirectly, via reflections within (the inner surfaces of) the light-guiding region. Using the latter configuration, no direct image of the light source may be created, and thus the optical system may be less dependent on the type of light source used. The shape and/or size of the light-guiding region may be determinative factors governing the intensity distribution of light output from the lighting device.

The at least one light-emitting element may for example include or be constituted by a solid state light emitter. Examples of solid state light emitters include LEDs, OLEDs, and laser diodes. Solid state light emitters are relatively cost efficient light sources since they in general are relatively inexpensive and have a relatively high optical efficiency and a relatively long lifetime. However, in the context of the present application, the term "light-emitting element" should be understood to mean substantially any device or element that is capable of emitting radiation in any region or combination of regions of the electromagnetic spectrum, for example the visible region, the infrared region, and/or the ultraviolet region, when activated e.g. by applying a potential difference across it or passing a current through it. Therefore a light-emitting element can have monochromatic, quasi- monochromatic, polychromatic or broadband spectral emission characteristics. Examples of light-emitting elements include semiconductor, organic, or polymer/polymeric LEDs, violet LEDs, blue LEDs, optically pumped phosphor coated LEDs, optically pumped nano-crystal LEDs or any other similar devices as would be readily understood by a person skilled in the art. Furthermore, the term light-emitting element can, according to one or more embodiments of the present invention, mean a combination of the specific light-emitting element or light- emitting elements which emit the radiation in combination with a housing or package within which the specific light-emitting element or light-emitting elements are positioned or arranged. For example, the term light-emitting element can encompass a bare LED die arranged in a housing, which may be referred to as a LED package.

The light in-coupling surface portion may for example be defined or delimited by, or substantially defined or delimited by, a spherical cap of the sphere lens. By a spherical cap, or spherical dome of the sphere lens it is meant a portion of a sphere (lens) cut off by a plane. If the plane includes the center of the sphere (lens), so that the height of the spherical cap is equal to the radius of the sphere (lens), the spherical cap may be called a hemisphere.

The at least one lighting module may comprise at least one carrier. The carrier may have a first side and a second side. The at least one light-emitting element may be coupled to the first side of the carrier. The carrier may for example comprise at least one printed circuit board (PCB). The first side and the second side may be arranged on opposite sides of the carrier.

For example, the carrier may be arranged with respect to the sphere lens such that the first side of the carrier substantially faces at least a selected portion of the light in- coupling surface portion. The carrier may be arranged at an angle to a tangent plane to the outer surface of the sphere lens, at a position on the selected portion of the light in-coupling surface portion, in which position the distance from the light in-coupling surface portion to the carrier is a minimum. The angle may for example be between about 30 degrees and about 60 degrees, although variations are possible and deviation from this angle interval is contemplated.

The outer surface of the sphere lens may comprise a light out-coupling surface portion, which may not be delimiting the light-guiding region.

According to an example, an optical axis of the lighting device, or the sphere lens, may be defined by an (imaginary) axis passing through a center position on the light out-coupling surface portion and a center position on the light in-coupling surface portion and the center of the sphere lens.

The carrier may be arranged so as to extend in a plane substantially parallel with or substantially perpendicular to the optical axis. A configuration with the carrier being arranged so as to extend in a plane substantially parallel with the optical axis has been found to facilitate or enable the lighting module, or the at least one light-emitting element, to be arranged at a relatively small distance to the sphere lens while still allowing for attaining arrangements of the at least one light-emitting element relatively to the (center of the) sphere lens which are relevant for example in road or street lighting applications.

A center position on the light out-coupling surface portion and a center position on the light in-coupling surface portion may for example be determined by means of calculating the centroid of the light out-coupling surface portion and the light in-coupling surface portion, respectively.

It is to understood that by "a center position" on the light out-coupling surface portion or on the light in-coupling surface portion it is not necessarily meant, e.g., the exact geometrical center position on the respective surface portion (although it may be, according to an example). Deviation from the exact geometrical center position on the respective surface portion is possible. According to an example, deviation from the exact geometrical center position on the respective surface portion within a distance of up to about 25% of the radius of the sphere lens from the exact geometrical center position is contemplated. According to another example, deviation from the exact geometrical center position on the respective surface portion may be defined as allowing for an angle of up to about 10 degrees to 15 degrees between the optical axis and an axis passing through the 'exact' center positions on light out-coupling surface portion and the light in-coupling surface portion and the center of the sphere lens.

In the context of the present application, by the carrier being arranged so as to extend in a plane "substantially parallel to the optical axis" and "substantially perpendicular to the optical axis", it is meant that the plane is not necessarily exactly parallel with or perpendicular to the optical axis, but that some deviations from being exactly parallel with or perpendicular to the optical axis is possible. For example, an angle between the plane and the optical axis of a few degrees (e.g. up to about 5 degrees) may be considered as "substantially parallel", and an angle between the plane and the optical axis between about 85 degrees and 95 degrees may be considered as "substantially perpendicular".

As indicated in the foregoing, the at least one light emitting element may be arranged at a distance from the sphere lens.

According to one example, the position of the at least one light emitting element as projected on the optical axis is outside an interval of the optical axis in which the sphere lens extends. According to another example, the position of the at least one light emitting element as projected on the optical axis is within the interval of the optical axis in which the sphere lens extends.

In view of the foregoing description, the selected arrangement of the at least one light-emitting element relatively to the (center of the) sphere lens for attaining a selected beam shape and direction of light coupled out from the sphere lens, may be achieved in different manners.

According to one example, the at least one lighting module may comprise a plurality of carriers, which are arranged in planes substantially perpendicular to the optical axis. At least some of the planes in which the carriers are arranged may intersect the optical axis at different positions along the optical axis. A different way to describe such a configuration is that the at least one lighting module may comprise one or more holes, which are not necessarily through- holes, and which allow for light-emitting elements to be positioned at different distances and orientations with respect to (the light in-coupling surface portion of) the sphere lens and/or the center of the sphere lens.

According to another example, the carrier may comprise at least one through- hole. A portion of the sphere lens may extend within or through the through-hole. The size of the at least one through-hole, e.g. its diameter, may determine how much of the sphere lens that may extend within or through the through-hole, and thus the distances and orientations of the light-emitting elements with respect to (the light in-coupling surface portion of) the sphere lens and/or the center of the sphere lens.

According to another example, the carrier may comprise at least one cutout.

That is, there may be at least one cutout in the carrier, e.g., at an edge thereof. A portion of the sphere lens may extend in the cutout.

The carrier may be at least in part flexible (i.e. at least a portion or portions of the carrier may be fiexible). For example, the carrier may include a flexible PCB. The carrier may be arranged in spaced relation to the light in-coupling surface portion such that the distance between the first side and the light in-coupling surface portion is substantially the same or even the same over the light in-coupling surface portion. Thus, the carrier may be configured so as to have a curved shape. Such a configuration may facilitate positioning the at least one light-emitting elements at selected angles with respect to sphere lens, for achieving the selected arrangement of the at least one light-emitting element relatively to the (center of the) sphere lens in order to attain a selected beam shape and direction of light coupled out from the sphere lens.

As indicated in the foregoing, the shape and/or size of the light-guiding region may at least in part determine the intensity distribution of light output from the lighting device outside any intensity peaks, while the selected arrangement of the at least one light- emitting element relatively to the (center of the) sphere lens may at least in part determine the shape and orientation on any intensity peak(s) of the light output from the lighting device. Generally, a relatively large light-guiding region may produce a broader intensity distribution of light output from the lighting device compared to a smaller light-guiding region.

Thus, the shape and/or size of the light-guiding region may be tailored or tuned for attaining a selected (or desired or required) beam shape and direction of light coupled out from the sphere lens.

For example, arranging the light-guiding region by an appropriate positioning of a wall or inner or outer surface of the light-guiding region may cause intensity peak(s) of the light output from the lighting device to exhibit relatively sharp intensity cut-offs. At least a portion of the light-redirection surface may for example extend in a plane which includes the center of the sphere lens. A different way to describe such a configuration is that a portion of the light-guiding region wall, e.g. at least a portion of the light-redirection surface, may be 'aligned' with the center of the sphere lens. In alternative or in addition, the light-guiding region may be arranged such that at least a portion thereof has a shape which is narrowing from a first side to a second side, substantially opposite to the first side. The shape may according to one example be characterized as similar to the shape of a funnel, or as being tapered. The first side and/or the second side may be portions of the light-redirection surface. The 'rate' of narrowing of the shape, i.e. how quickly or to what extent the shape narrows from the first side to the second side, can be selected in order to facilitate attaining a selected beam shape and direction of light coupled out from the sphere lens. An alternative way to describe that the light-guiding region may be arranged such that at least a portion thereof has a shape which is narrowing from a first side to a second side, substantially opposite to the first side, is that a cross section of the at least a portion of the light-guiding region is gradually decreasing towards the second side. By arranging the light-guiding region such that at least a portion thereof has a shape which is narrowing from a first side to a second side, substantially opposite to the first side, intensity peak(s) of the light output from the lighting device may be caused to exhibit relatively sharp intensity cut-offs, which may help in reducing glare or keeping it within an acceptable level.

The lighting device may comprise at least one heat transferring element for transferring heat, e.g. generated by the at least one light-emitting element when in use, away from the at least one light-emitting element.

For example the second side of the carrier may be coupled to the heat transferring element in order to transfer heat, generated by the at least one light-emitting element when in use, away from the at least one light-emitting element. The heat transferring element may for example include a heat sink, a heat spreader, and/or heat pipe. In alternative or in addition, a heat transferring element may be (thermally) coupled to the at least one lighting module, for transferring heat generated by the lighting module or the at least one light-emitting element when in use. In alternative or in addition, the carrier itself may be configured to transfer heat, generated by the at least one light-emitting element when in use, away from the at least one light-emitting element. Thus the carrier may be configured so as to exhibit a heat transferring capacity and/or functionality.

The lighting device may comprise a light-transmissive substrate which is configured to support the sphere lens. The light-transmissive substrate may have varying shapes. For example, the light-transmissive substrate may comprise a semi-spherical recess for supporting the sphere lens. According to another example, the light-transmissive substrate may comprise a semi-cylindrical recess for supporting the sphere lens. For example, the sphere lens may be arranged so as to 'rest' in the semi-spherical recess or the semi- cylindrical recess. According to yet another example, the light-transmissive substrate may be substantially planar, and/or flat. The light-transmissive substrate may be transparent or translucent, or may include at least one portion that is transparent and at least one portion that is translucent. The light-transmissive substrate may provide for a mechanical fixation of components of the lighting device such as the sphere lens and the least one lighting module. The light-transmissive substrate can be used for at least in part enclosing at least some components of the lighting device such as the sphere lens, the lighting module or the light- guiding region. The light-transmissive substrate can be used for sealing or protecting at least some components of the lighting device such as the sphere lens, the lighting module or the light-guiding region against moisture and/or dust. Sealing may be performed for example by means of employing optical adhesive or glue.

The lighting device may comprise a holder for the sphere lens. The holder may according to embodiments of the present invention be referred to as a lens plate.

The holder may be arranged to hold the sphere lens at a spherical segment of the sphere lens. The spherical segment may for example include or be constituted by an equator of the sphere lens. The holder may be transparent or translucent, or it may include at least one portion that is transparent and at least one portion that is translucent. The holder may be arranged substantially perpendicular to the optical axis. Arranging the holder so as to hold the sphere lens at an equator of the sphere lens and with the holder arranged

substantially perpendicular to the optical axis may have a relatively small impact on the optical function of the lighting module and sphere lens.

Similarly to employing a light-transmissive substrate such as described above, the holder can be used for at least in part enclosing at least some components of the lighting device such as the sphere lens, the lighting module or the light-guiding region. Further, the holder can be used for sealing or protecting at least some components of the lighting device such as the sphere lens, the lighting module or the light-guiding region against moisture and/or dust. Sealing may be performed for example by means of employing optical adhesive or glue.

The light-transmissive substrate and/or the holder, or lens plate, may for example include one or more materials selected for example from the group including PMMA (sometimes referred to as acrylic glass), polycarbonate, glass, silicone and/or silicone rubber. According to a second aspect, there is provided a lighting system which comprises a plurality of lighting devices according to the first aspect. The lighting system may for example comprise an outdoor lighting system for illumination of a road and/or a street. Each of the lighting devices may for example be arranged on top of a pole for illuminating the road or street from above.

Further objects and advantages of the present invention are described in the following by means of exemplifying embodiments. It is noted that the present invention relates to all possible combinations of features recited in the claims. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the description herein. Those skilled in the art realize that different features of the present invention can be combined to create embodiments other than those described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplifying embodiments of the invention will be described below with reference to the accompanying drawings.

Fig. 1 is a cross-sectional view of a lighting device according to an embodiment of the present invention.

Fig. 2 is a schematic perspective view of a lighting device according to an embodiment of the present invention.

Figs. 3-14 are cross-sectional views of lighting devices according to different embodiments of the present invention.

All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate embodiments of the present invention, wherein other parts may be omitted or merely suggested.

DETAILED DESCRIPTION

The present invention will now be described hereinafter with reference to the accompanying drawings, in which exemplifying embodiments of the present invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will convey the scope of the invention to those skilled in the art.

In the drawings, identical reference numerals denote the same or similar components having a same or similar function, unless specifically stated otherwise. Figure 1 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 comprises a sphere lens 110 for focusing light. The lighting device 100 comprises a lighting module 120, which is configured to emit light 130. The lighting module 120 comprises two light-emitting elements 125, which is according to an example. The lighting module 120 may according to one or more examples comprise tens or hundreds of light-emitting elements, or even more. Although the lighting device 100 illustrated in Figure 1 includes a single lighting module 120, it is to be understood that this is according to an example. According to one or more examples, the lighting device 100 may comprise two or more lighting modules, for example five or ten or even more lighting modules.

According to the embodiment of the present invention illustrated in Figure 1 , the lighting module 120 may for example comprise a carrier, including a first side 121 and a second side 122. As indicated in Figure 1, the light-emitting elements 125 are coupled to the first side 121 of the carrier. The carrier may for example comprise or be constituted by a PCB.

The lighting module 120 is arranged with respect to the sphere lens 110 so as allow light emitted from the light-emitting elements 125 to be coupled into the sphere lens 110 via a light in-coupling surface portion 111 of an outer surface of the sphere lens 110. The lighting module 120 is configured in relation to the sphere lens 110 so as to provide for a selected arrangement of the light-emitting elements 125 relatively to the center of the sphere lens 110, for attaining a selected beam shape and direction of light 140 coupled out from the sphere lens 110.

The lighting device 100 comprises a light-guiding region 140 delimited at least by a light-redirection surface 142 of a light-redirection element 141 and the light in-coupling surface portion 111. The light-guiding region 140 encloses the light-emitting elements 125 so as to guide light emitted by the light-emitting elements 125 towards the light in-coupling surface portion 111.

The outer surface of the sphere lens 110 comprises a light out-coupling surface portion 150, via which light can be coupled out from the sphere lens 110. The dashed line 135 indicates light that is output from the sphere lens 110 and which has been indirectly coupled into the sphere lens 110, by reflection at the light-redirection surface 142, as illustrated in Figure 1. The solid lines 135 indicate light that is output from the sphere lens 110 and which has been directly coupled into the sphere lens 110, as illustrated in Figure 1. An optical axis of the lighting device 100, or sphere lens 110, may be defined by an (imaginary) axis passing through a center position on the light out-coupling surface portion 150 and a center position on the light in-coupling surface portion 111. According to the embodiment of the present invention illustrated in Figure 1 , the optical axis extends vertically through the center of the sphere lens, from the uppermost point of the cross section of the sphere lens 110 depicted in Figure 1 to its lowermost point. In accordance with the embodiment of the present invention illustrated in Figure 1 , the carrier included in or constituting the lighting module 120 may be arranged so as to extend in a plane substantially perpendicular to the optical axis.

Further in accordance with the embodiment illustrated in Figure 1, the lighting device 100 may comprise a heat transferring element 160 for transferring heat, e.g. generated by the light-emitting elements 125 when in use, away from the light-emitting elements 125. As illustrated in Figure 1, the heat transferring element 160 may be (thermally) coupled to the second side 122 of the carrier. The heat transferring element 160 may for example include a heat sink, a heat spreader, and/or a heat pipe.

Figure 2 is a schematic perspective view of a lighting device 100 according to another embodiment of the present invention.

The lighting device 100 comprises a sphere lens 110 for focusing light. The center of the sphere lens 110 defines the origin of a coordinate system x, y, z, as illustrated in Figure 2.

The lighting device 100 comprises a lighting module 120 which is configured to emit light. The lighting module 120 comprises at least one light-emitting element. The lighting module 120 may for example comprise a few or tens of light-emitting elements, or even more. Although one lighting module 120 is depicted in Figure 2, it is to be understood that this is according to an example. According to examples, the lighting device 100 may comprise more than one lighting modules, for example two, five, or ten or more lighting modules. The lighting module 120 is arranged with respect to the sphere lens 110 so as allow light emitted from the at least one light-emitting element to be coupled into the sphere lens 110 via a light in-coupling surface portion of an outer surface of the sphere lens 110. The lighting module 120 is configured in relation to the light in-coupling surface portion of the sphere lens 110 so as to provide for a selected arrangement of the at least one light-emitting element relatively to the sphere lens 110, for attaining a selected beam shape and direction of light coupled out from the sphere lens 1 10. The lighting device 100 comprises a light-guiding region, schematically indicated by reference numeral 140 in Figure 2, which is delimited at least by light- redirection surfaces 142 of a light-redirection element, and the light in-coupling surface portion. The light-guiding region 140 at least in part encloses the at least one light-emitting element so as to guide light emitted by the at least one light-emitting element towards the light in-coupling surface portion.

In accordance with the embodiment illustrated in Figure 2, the lighting device 100 may comprise a heat transferring element 160 for transferring heat, e.g. generated by the light-emitting elements when in use, away from the light-emitting elements. As illustrated in Figure 2, the heat transferring element 160 may be (thermally) coupled to the lighting module 120. The heat transferring element 160 may for example include a heat sink, a heat spreader, and/or a heat pipe.

With reference for example to any of the embodiments of the present invention described above with reference to Figures 1 and 2, the shape and/or size of the light-guiding region 140 may at least in part determine the intensity distribution of light output from the lighting device 100 outside any intensity peaks, while the selected arrangement of the light-emitting element(s) 125 relatively to the (center of the) sphere lens 110 may at least in part determine the shape and orientation on any intensity peak(s) of the light output from the lighting device 100. Generally, a relatively large light-guiding region 140 may produce a broader intensity distribution of light output from the lighting device 100, compared to a smaller light-guiding region 140. The shape and/or size of the light-guiding region 140 may hence be tailored or tuned in order to attain a selected (or desired or required) beam shape and direction of light coupled out from the sphere lens 110, and possibly subsequently from the lighting device 100.

Referring now to Figures 3, 4 and 14, there are shown cross-sectional views of lighting devices 100 according to different embodiments of the present invention, for illustrating ways in how the shape and/or size of the light-guiding region 140 may be selected. Each of Figures 3, 4 and 14 shows a cross section of the lighting device 100 in the z-x plane, using a coordinate system x, y, z similar to the one illustrated in Figure 2. The y- axis is hence directed perpendicular to the plane of the drawings, and directed towards the viewer.

With reference to Figure 3, the light-guiding region 140 may be arranged such that a portion of the light-redirection surface 142 extends in a plane which includes the center of the sphere lens 110. In accordance with the embodiment of the present invention illustrated in Figure 3, the portion of the light-redirection surface 142, which portion extends in a plane which includes the center of the sphere lens 110, extends in the y-z plane. A different way to describe such a configuration is that a portion of the light-guiding region 140 wall, e.g. a portion of the light-redirection surface 142, may be 'aligned' with the center of the sphere lens 110.

In alternative or in addition, and with reference to Figure 4, the light-guiding region 140 may be arranged such that a portion thereof has a shape which is narrowing from a first side 143 to a second side 144, the second side 144 being arranged substantially opposite to the first side 143. The portion of the light-guiding region 140 may hence be tapered, or such that a cross section of the portion of the light-guiding region 140 (in the x-y plane, referring to Figure 4) is gradually decreasing towards the second side 144. The first side 143 and/or the second side 144 may be portions of the light-redirection surface 142. The 'rate' of narrowing of the shape, i.e. how quickly or to what extent the shape the shape narrows from the first side 143 to the second side 144, can be selected in order to facilitate attaining a selected beam shape and direction of light coupled out from the sphere lens 110, and possibly subsequently from the lighting device 100. For example, in accordance with the embodiment of the present invention illustrated in Figure 4, an angle between the surface 145 (which surface 145 according to the illustrated example extends in a plane which includes the center of the sphere lens 110) and the z-axis may be selected appropriately, in order to facilitate attaining a selected beam shape and direction of light coupled out from the sphere lens 110, and possibly subsequently from the lighting device 100. The surface 145 may be a portion of the light-redirection surface 142.

In alternative or in addition, and with reference to Figure 14, the light-guiding region 140 may be arranged such that a portion of the light-redirection surface 142 extends in a plane which includes the center of the sphere lens 110. The surface 145 of the light guiding region 140 is delimited by a cone with the top of the cone coinciding with the center of the sphere lens, (the cone may be viewed as a collection of planes through the center of the sphere lens, rotated around the z-axis). The cone cross-sections are indicated by the dashed lines 147, the curved line 146 indicates the cross-section of the cone with the sidewalls of the light guiding region. The angle of the cone to the horizontal (xy) plane is for example 10 degrees, which gives a cut-off in the intensity distribution at about 80 degrees with respect to the z-axis. This embodiment enables a light-guiding region 140 with an improved glare cutoff. As illustrated in Figure 3, the lighting device 100 may comprise a plurality of light-emitting elements 125 arranged in a cluster- like configuration. As illustrated in Figures 4 and 14, the lighting device 100 may comprise a plurality of light-emitting elements 125 arranged in a string-like configuration. Only some of the light-emitting elements 125 depicted in Figures 3 and 4 are indicated by reference numerals 125. Figure 5 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 illustrated in Figure 5 is similar to the lighting device 100 illustrated in Figure 1 , and identical reference numerals in Figures 1 and 5 denote the same or similar components having generally the same or similar function. A difference between the lighting device 100 illustrated in Figure 5 and the lighting device 100 illustrated in Figure 1 is that the lighting device 100 illustrated in Figure 5 has a carrier included in or constituting the lighting module 120, which carrier is at least in part flexible and is arranged in spaced relation to the light in-coupling surface portion 111 such that the distance between the first side 121 of the carrier and the light in-coupling surface portion 111 is substantially the same, or the same, over the light in-coupling surface portion 111. The carrier may for example include a flexible PCB. As illustrated in Figure 5, the carrier may hence have a curved shape or configuration. Such a configuration may facilitate positioning of the light-emitting elements 125 at selected positions with respect to sphere lens 110, for achieving the selected arrangement of the light-emitting element 125 relatively to the (center of the) sphere lens 110 for attaining a selected beam shape and direction of light coupled out from the sphere lens 110. As indicated in Figure 5, the heat transferring element 160 may be at least in part flexible and/or curved.

Figure 6 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 illustrated in Figure 6 is similar to the lighting device 100 illustrated in Figure 1, and identical reference numerals in Figures 1 and 6 denote the same or similar components having generally the same or similar function.

An optical axis of the lighting device 100, or sphere lens 110, may be defined by an (imaginary) axis OA passing through a center position on the light out-coupling surface portion 150 and a center position on the light in-coupling surface portion 111. According to the embodiment of the present invention illustrated in Figure 6, the optical axis extends vertically through the center of the sphere lens, from the uppermost point of the cross section of the sphere lens 110 depicted in Figure 6 to its lowermost point. A difference between the lighting device 100 illustrated in Figure 6 and the lighting device 100 illustrated in Figure 1 is that in the lighting device 100 illustrated in Figure 6, the carrier included in or constituting the lighting module 120 is arranged so as to extend in a plane substantially parallel to the optical axis OA. The inventors have realized that with a such an orientation of the carrier, there may be facilitated to position the light- emitting elements 125 at a relatively small distance to the sphere lens 110, in particular for realizing arrangement of the light-emitting element 125 relatively to the (center of the) sphere lens 110 in order to attain a selected beam shape and direction of light coupled out from the sphere lens 110 relevant for road or street lighting applications.

Figure 7 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 illustrated in Figure 7 is similar to the lighting device 100 illustrated in Figure 1, and identical reference numerals in Figures 1 and 7 denote the same or similar components having generally the same or similar function.

An optical axis of the lighting device 100, or sphere lens 110, may be defined by an (imaginary) axis OA passing through a center position on the light out-coupling surface portion 150 and a center position on the light in-coupling surface portion 111. According to the embodiment of the present invention illustrated in Figure 7, the optical axis extends vertically through the center of the sphere lens 110, from the uppermost point of the cross section of the sphere lens 110 depicted in Figure 7 to its lowermost point.

A difference between the lighting device 100 illustrated in Figure 7 and the lighting device 100 illustrated in Figure 1 is that in the lighting device 100 illustrated in Figure 7, the lighting module 120 comprises two carriers, each being arranged in planes substantially perpendicular to the optical axis OA, which planes intersect the optical axis at different positions along the optical axis OA.

Figure 8 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 comprises a lighting module 120 comprising a carrier, including a first side 121 and a second side 122. In accordance with the embodiment illustrated in Figure 8, the carrier comprises three through-holes. The lighting device 100 comprises three sphere lenses 110, and three light-guiding regions 140 corresponding to respective ones of the three sphere lenses 110. Only one of the

arrangements of sphere lens 110, light-guiding region 140 and lighting module 120 depicted in Figure 8 is provided with reference numerals. Each of the light-guiding regions 140 encloses a light-emitting element 125, each of which is coupled to the first side 121 of the carrier. For the leftmost sphere lens 110, a portion of the sphere lens 110 extends within the corresponding through-hole, as indicated in Figure 8. For the middle sphere lens 110 and the rightmost sphere lens 110, a portion of the sphere lens 110 extends through the corresponding through-hole, as indicated in Figure 8. The size of the through-hole, e.g. its diameter, may determine how much of the sphere lens 110 that may extend within or through the through- hole, and thus the distances and orientations of the light-emitting element(s) 125 with respect to (the light in-coupling surface portion 111 of) the sphere lens 110.

Figure 9 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 illustrated in Figure 9 is similar to the lighting device 100 illustrated in Figure 1, and identical reference numerals in Figures 1 and 9 denote the same or similar components having generally the same or similar function. The lighting device 100 illustrated in Figure 9 includes two sphere lenses 110 and two light-guiding regions 140 corresponding to respective ones of the two sphere lenses 110. Each of the light-guiding regions 140 encloses a light-emitting element 125 included in a lighting module 120 comprising a carrier. The light-emitting element 125 is arranged on the first side 121 of the carrier.

As illustrated in Figure 9 with reference to the rightmost arrangement of sphere lens 110, light-guiding region 140 and lighting module 120, the carrier may be arranged with respect to the sphere lens 110 such that the first side 121 substantially faces at least a selected portion of the light in-coupling surface portion 111. As illustrated in Figure 9, the carrier may be arranged at an angle a to a tangent plane TP to the outer surface of the sphere lens 110 at a position on the selected portion of the light in-coupling surface portion 111. The angle may for example be between about 30 degrees and about 60 degrees, or between about 35 degrees and about 55 degrees, or between about 40 degrees and about 50 degrees. According to such a configuration, the carrier or lighting module 120 may be arranged parallel with a vertical direction which may constitute a main direction of light output from the lighting device 100. According to the embodiment illustrated in Figure 9, the vertical direction extends vertically through the center of the sphere lens 110, from the uppermost point of the cross section of the sphere lens 110 depicted in Figure 9 to its lowermost point. The inventors have realized that with a such an orientation of the carrier, there may be facilitated to position the light-emitting elements 125 at a relatively small distance to the sphere lens 110, in particular for realizing arrangement of the light-emitting element 125 relatively to the sphere lens 110 in order to attain a selected beam shape and direction of light coupled out from the sphere lens 110 relevant for road or street lighting applications.

Figure 10 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 illustrated in Figure 10 is similar to the lighting device 100 illustrated in Figure 9, and identical reference numerals in Figures 9 and 10 denote the same or similar components having generally the same or similar function. A difference between the lighting device 100 illustrated in Figure 10 and the lighting device 100 illustrated in Figure 9 is that in the lighting device 100 illustrated in Figure 10, is that there is a gap between the heat transferring elements 160 which correspond to the two arrangements of sphere lens 110, light-guiding region 140 and lighting module

120. The gap may for example allow for a flow of fluid, e.g. air, between the heat transferring elements 160, which may facilitate transfer of heat away from the heat transferring elements 160 by means of convective heat transfer from outer surfaces of the heat transferring elements 160.

Figure 11 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 illustrated in Figure 11 is similar to the lighting device 100 illustrated in Figure 1, and identical reference numerals in Figures 1 and 11 denote the same or similar components having generally the same or similar function. A difference between the lighting device 100 illustrated in Figure 11 and the lighting device 100 illustrated in Figure 1 is that in the lighting device 100 illustrated in

Figure 11, the lighting module 120 or the light-emitting elements 125 are arranged in relation to the light in-coupling surface portion 111 of the sphere lens 110 so as to enable light emitted by lighting module 120 or light-emitting elements 125 to be substantially indirectly coupled into the light in-coupling surface portion 111, with only a relatively small fraction of the light emitted by the lighting module 120 or lighting elements 125 being directly coupled into the light in-coupling surface portion 111. Light may be able to reach the sphere lens 110 substantially indirectly, via reflections within the light-guiding region 140. Thereby, no direct image of the light source (light-emitting elements 125) may be created on a surface (not shown in Figure 11) illuminated by the lighting device 100.

Figure 12 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 illustrated in Figure 12 is similar to the lighting device 100 illustrated in Figure 6, and identical reference numerals in Figures 6 and 12 denote the same or similar components having generally the same or similar function. A difference between the lighting device 100 illustrated in Figure 12 and the lighting device 100 illustrated in Figure 6 is that the lighting device 100 illustrated in Figure

12 comprises a light-transmissive substrate 170 which is configured to support the sphere lens 110. The light-transmissive substrate 170 may for example be coupled or connected to the heat transferring element(s) 160, such as illustrated in Figure 12. However, according to one or more other embodiments of the present invention, the light-transmissive substrate 170 may be coupled or connected to other component(s) of the lighting device 100 so as to allow for supporting the sphere lens 110. The light-transmissive substrate 170 may for example be coupled or connected to the heat transferring element(s) 160 or to another component(s) by means of optical adhesive or glue, schematically indicated in Figure 12 by reference numeral 175.

Figure 13 is a cross-sectional view of a lighting device 100 according to an embodiment of the present invention. The lighting device 100 illustrated in Figure 13 is similar to the lighting device 100 illustrated in Figure 6, and identical reference numerals in Figures 6 and 13 denote the same or similar components having generally the same or similar function. A difference between the lighting device 100 illustrated in Figure 13 and the lighting device 100 illustrated in Figure 6 is that the lighting device 100 illustrated in Figure

13 comprises a holder, or lens plate, 170, for the sphere lens 110. As illustrated in Figure 13, the holder 180 may be arranged to hold the sphere lens at an equator of the sphere lens 110. The holder 180 may be transparent or translucent, or it may include at least one portion that is transparent and at least one portion that is translucent. The holder 180 may be arranged substantially perpendicular to the optical axis OA. Arranging the holder 180 so as to hold the sphere lens 110 at an equator of the sphere lens 110, and with the holder 180 being arranged substantially perpendicular to the optical axis OA, may have a relatively small impact on the optical function of the lighting module 120 and sphere lens 110. The holder 180 may for example be coupled or connected to the heat transferring element(s) 160, such as illustrated in Figure 13. However, according to one or more other embodiments of the present invention, the holder 180 may be coupled or connected to other component(s) of the lighting device 100. The holder 180 may for example be coupled or connected to the heat transferring element(s) 160 or to another component(s) by means of optical adhesive or glue,

schematically indicated in Figure 13 by reference numeral 185.

In conclusion, a lighting device is disclosed, comprising a sphere lens. A lighting module comprising at least one light-emitting element is arranged with respect to the sphere lens so as allow light emitted from the at least one light-emitting element to be coupled into the sphere lens via a light in-coupling surface portion of the sphere lens. The lighting module is configured in relation to the sphere lens so as to provide for a selected arrangement of the at least one light-emitting element relatively to the center of the sphere lens, for attaining a selected beam shape and direction of light coupled out from the sphere lens. A light-guiding region is delimited at least by a light-redirection surface and the light in- coupling surface portion. The light-guiding region at least in part encloses the at least one light-emitting element so as to guide light emitted by the at least one light-emitting element towards the light in-coupling surface portion.

While the present invention has been illustrated in the appended drawings and the foregoing description, such illustration is to be considered illustrative or exemplifying and not restrictive; the present invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the appended claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A lighting device (100) comprising:

a sphere lens (110) for focusing light;

at least one lighting module (120) configured to emit light (130), wherein the lighting module comprises at least one light-emitting element (125) arranged with respect to the sphere lens so as allow light emitted from the at least one light-emitting element to be coupled into the sphere lens via a light in-coupling surface portion (111) of an outer surface of the sphere lens, wherein the at least one lighting module is configured in relation to the sphere lens so as to provide for a selected arrangement of the at least one light-emitting element relatively to the center of the sphere lens for attaining a selected beam shape and direction of light coupled out from the sphere lens; and

a light-guiding region (140) delimited at least by a light-redirection surface (142) of a light-redirection element (141) and the light in-coupling surface portion, wherein the light-guiding region at least in part encloses the at least one light-emitting element so as to guide light emitted by the at least one light-emitting element towards the light in-coupling surface portion, and wherein the light guiding region is arranged such that at least a portion of the light-redirection surface extends in a plane which includes the center of the sphere lens.

2. A lighting device according to claim 1, wherein the lighting module is arranged relatively to the sphere lens such that each of the at least one light-emitting element is arranged at a radial distance from the center of the sphere lens which is larger than the focal distance F of the sphere lens.

3. A lighting device according to claim 1 or 2, wherein the at least one lighting module comprises at least one carrier, having a first side (121) and a second side (122), wherein the at least one light-emitting element is coupled to the first side of the carrier.

4. A lighting device according to claim 3, wherein the carrier is arranged with respect to the sphere lens such that the first side substantially faces at least a selected portion of the light in-coupling surface portion, wherein the carrier is arranged at an angle (a) to a tangent plane (TP) to the outer surface of the sphere lens at a position on the selected portion of the light in-coupling surface portion in which position the distance from the light in- coupling surface portion to the carrier is a minimum, said angle being between about 30 degrees and about 60 degrees.

5. A lighting device according to claim 3 or 4, wherein the outer surface of the sphere lens comprises a light out-coupling surface portion (150), which is not delimiting the light-guiding region, and wherein an optical axis (OA) of the lighting device is defined by an axis passing through a center position on the light out-coupling surface portion and a center position on the light in-coupling surface portion and the center of the sphere lens, and wherein the carrier is arranged so as to extend in a plane substantially parallel with or substantially perpendicular to the optical axis.

6. A lighting device according to claim 3 or 4, wherein the outer surface of the sphere lens comprises a light out-coupling surface portion (150), which is not delimiting the light-guiding region, and wherein an optical axis (OA) of the lighting device is defined by an axis passing through a center position on the light out-coupling surface portion and a center position on the light in-coupling surface portion and the center of the sphere lens, and wherein the at least one lighting module comprises a plurality of carriers arranged in planes substantially perpendicular to the optical axis, wherein at least some of the planes intersect the optical axis at different positions along the optical axis.

7. A lighting device according to any one of claims 3-6, wherein the carrier comprises at least one through-hole or a cutout, and wherein a portion of the sphere lens extends within or through the through-hole or in the cutout.

8. A lighting device according to claim 3, wherein the carrier is at least in part flexible and is arranged in spaced relation to the light in-coupling surface portion such that the distance between the first side and the light in-coupling surface portion is substantially the same over the light in-coupling surface portion.

9. A lighting device according to any one of claims 1-8, wherein the light- guiding region is arranged such that at least a portion thereof has a shape which is narrowing from a first side (143) to a second side (144), substantially opposite to the first side.

10. A lighting device according to any one of claims 1-8, wherein the light- guiding region is arranged such that a surface 145 of the light guiding region 140 is delimited by a cone with the top of the cone coinciding with the center of the sphere lens.

11. A lighting device according to any one of claims 1-10, wherein the lighting module comprises a plurality of light-emitting elements, and wherein the lighting module comprises a plurality of allowed positions in which light-emitting elements can be arranged, the number of allowed positions exceeding the number of light-emitting elements, wherein the selected arrangement of the at least one light-emitting element relatively to the center of the sphere lens is attainable by the plurality of light-emitting elements being arranged in selected ones of some of the allowed positions.

12. A lighting device according to any one of claims 1-10, wherein the lighting module comprises a plurality of light-emitting elements, and wherein at least two subsets of the plurality of light-emitting elements are individually controllable with respect to emission of light for attaining the selected beam shape and direction of light coupled out from the sphere lens.

13. A lighting device according to claim 12, wherein each of the plurality of light- emitting elements is individually controllable with respect to emission of light for attaining the selected beam shape and direction of light coupled out from the sphere lens.

14. A lighting device according to any one of claims 1-13, further comprising a light-transmissive substrate (170) configured to support the sphere lens and/or a holder (180) for the sphere lens.

15. A lighting system comprising a plurality of lighting devices (100) according to any one of claims 1-14.