Patent Description:
Different types of lighting arrangements are known which use optical elements such as collimators, reflectors and/or lenses to transform light emitted from a light source to a desired illumination beam pattern.

<CIT> describes a lens element for a light source, in particular for an LED. The lens element comprises a body of light conducting material. The body conducts portions of light originating from the light source. Portions of the light are reflected as a consequence of total reflection at boundary surfaces of the body.

<CIT> refers to a headlight with an optical element with a base section and a head section, where a lower side of the base section runs along a light beam direction before a light source i.e. LED, below a vertical opening angle.

<CIT> discloses an illuminating device for vehicles in which a light conductor made of light transmissive material having a predetermined light refractive index is placed between an outgoing light end of an optical cable and an incident light end of a lens body.

<CIT> refers to an headlamp for a vehicle including a holder for a light-distribution optical fiber of the type that has an output end emanating light of known spatial-intensity distribution, an optical coupler that has an input end adjacent the holder and includes a plurality of elements, each of which is positioned to receive light from a selected area of the light of known spatial intensity distribution and to alter the intensity or spatial distribution of that light to provide a predetermined spatial intensity distribution at an output of said coupler, and a projection lens to project the predetermined spatial intensity distribution to a desired illumination pattern.

<CIT> discloses a lighting unit including an LED light source, and a lens body light exiting surface greater in width than in thickness. The lens body can include a first optical system, a second optical system, and a third optical system.

It may be considered an object to propose a lighting arrangement to achieve a desired illumination beam pattern suited for a vehicle headlamp, in particular from a compact light source.

According to an aspect of the invention, a lighting arrangement according to claim <NUM> is proposed. Dependent claims refer to preferred embodiments.

The lighting arrangement according to the invention includes a light source and a beam shaping arrangement with a light input portion and a light output portion. Light from the light source is received at the light input portion and emitted as a shaped beam at the light output portion. The light input portion is a light input surface, and the light output portion may be a light output area or surface. A forward direction may be defined from the light input portion into the direction of the light output portion, e.g. from a center of a light input surface to a center of a light output surface.

As will become apparent in the following description, and in particular from the preferred embodiments of the invention, the beam shaping arrangement may have several different embodiments, and may include one or more types of optical elements to guide, shape, reflect, and/or otherwise optically modify the light from the light input portion before it is emitted at the light output portion.

In the claims and following description, reference will be made to dimensions and/or directions, such as a height direction and lateral directions. These directions may be understood relative to the above defined forward direction being arranged at least substantially horizontally. While an at least generally horizontal arrangement will be the preferred orientation in operation of the lighting arrangement, for example in a vehicle head lamp, the skilled person will understand that there may be situations or uses where the lighting arrangement can be oriented differently. Thus, reference to the above directions is only intended to clarify the relative arrangement and should not be understood as limiting the orientation in which the lighting arrangement may be operated.

The beam shaping arrangement is disposed to divide light from the light input portion into at least two separate beam portions. These include at least a first and a second beam portion separated in a height direction. Thus, the first and second beam portion may be distinguished in that they follow different corresponding beam paths arranged at different height within the beam shaping arrangement, and/or that they are directed under different angles of inclination relative to the forward direction. For example, a dividing angle of inclination may be defined, e.g. relative to the horizontal direction, such that the first beam portion may include light emitted under angles of inclination greater than the dividing angle of inclination, and the second beam portion may include light emitted under angles of inclination less than the separating angle of inclination.

The beam shaping arrangement is disposed such that the first and second beam portions are led to converge in the height direction at or towards said light output portion. In this context, the term "converge" is not intended to designate the spread of beam directions within the first and second beam portions, but should be understood as referring to the fact that the first and second beam portions are brought together in the height direction at the light output portion. Thus, the first and second beam portions, which are separated in the height direction at least in a portion of the beam shaping arrangement, are again brought together at the light output portion. As will be apparent in connection with preferred embodiments, the first and second beam portions may be arranged at the light output portion at at least substantially the same height.

According to an aspect of the invention, the first and second beam portions are however differently directed into lateral directions, relative to the forward direction. At the light output portion, the second beam portion is arranged and/or directed laterally further outward relative to the first beam portion. The term "laterally outward" may be understood relative to a center of the light output portion.

At the light output portion, the first and second beam portions are thus emitted laterally offset from each other.

Thus, the beam shaping arrangement may achieve a beam to be emitted at the light output portion which may be wider in at least one, preferably both lateral directions than the input beam received at the light input portion. Such a broadened beam is particularly preferred for automotive front lighting. According to an underlying concept of the invention, such a broader beam is formed from two or more beam portions initially separated in the height direction. Thus, in the beam path from the light source up to the light output portion, a spread of emitted light in the height direction is transformed into a spread into lateral directions. The intensity distribution may thus be transformed to match the aperture of further optical elements, such as a projection lens. In this way, it is possible to obtain a wide output beam in a very efficient way.

In accordance with the widening of the output beam, the dimensions of the light output portion may be such that its lateral width corresponds to more than twice its height or thickness (measured at the thickest portion), preferably more than four times. The height of the light output portion may preferably be less than <NUM> times the height of the light input portion, further preferably less than <NUM> times. The width or lateral extension of the light output portion may preferably be more than <NUM> times the width of the light input portion, further preferably more than <NUM> times.

The general concept of the above described aspects of the invention of using height separated beam portions to obtain a laterally spread output beam pattern may be used in different embodiments and combinations, some of which will be further described below.

The first beam portion is a center beam, which is directed to a center portion of the light output portion. The second beam portion is a peripheral beam, directed to a peripheral portion of the light output portion, thus laterally further outward relative to the first beam portion.

In a particularly preferred embodiment, the peripheral beam may be directed to a first lateral side of the center portion, e.g. to the right, and at least one further beam portion may be directed to the second, opposite lateral side, e.g. to the left. Particularly, the arrangement may be at least substantially symmetrical with regard to the lateral directions. For example, while the first beam portion may be directed to the center portion of the light output portion, one or more peripheral beams may be directed to peripheral portions on one side, and the same number of peripheral beams may be directed to the opposite side of the center portion at the light output portion.

According to a further preferred embodiment, the first beam portion may be a first peripheral beam, which is directed to a first peripheral portion at the light output portion, and the second beam portion may be a second peripheral beam, directed to a second peripheral portion arranged laterally further outward relative to the first peripheral portion. Thus, the first and second beam portions, separated in height direction, may both be directed towards peripheral portions, however one further outward relative to the other. Thus, again, a broadened beam may be achieved.

In a particularly preferred embodiment, a first and a second peripheral portion may be arranged on a first lateral side of the light output portion, and further beam portions may be arranged on a second, opposite lateral side of the light output portion. The arrangement may preferably be at least substantially symmetrical. Thus, for example four peripheral portions may be provided, two to each lateral side.

In a particularly preferred embodiment, light may be divided into at least a first, second and third beam portion, separated in the height direction. The first beam portion may be a center beam directed to a center portion of the light output portion. The second beam portion may be a first peripheral beam directed to a first peripheral portion of the light output portion, and the third beam portion may be a second peripheral beam, directed to a second peripheral portion arranged laterally further outward relative to the first peripheral portion. As will be shown for preferred embodiments, a separation of at least three different beam portions in height may thus be used to achieve a particularly widely spread output beam. Also, for this embodiment, an at least substantially symmetrical arrangement is preferred, for example with the first and second peripheral portions arranged to one lateral direction of the center portion, and further beam portions arranged towards a second, opposite lateral side.

According to further preferred embodiments of the invention, the beam shaping arrangement may include at least one lateral reflection surface to reflect at least one of the beam portions into a lateral direction. This may be used to achieve the desired broadened beam in lateral direction. Particularly preferably, the beam shaping arrangement may include at least a first and a second lateral reflection surface. The first lateral reflection surface may be disposed to reflect one or more of the beam portions into a lateral direction towards the second lateral reflection surface, and the second lateral reflection surface may be disposed to direct the beam portion into a direction at least substantially parallel to the forward direction toward the light output portion. Thus, by twice reflecting at least one of the beam portions at the first and second lateral reflection surface, beams may be directed to peripheral portions of the light output portion while being oriented at least substantially parallel to the forward direction.

According to a preferred embodiment, at least one of the beam portions may be led within the beam shaping arrangement to first diverge from the forward direction in the height direction, and then converge toward the forward direction in the height direction. Again, the terms "converging" and "diverging" should not be understood as to refer to increased or reduced spread of the beam portion itself, but to designate the direction of the beam portion relative to the forward direction. According to the preferred embodiment, for example the first beam portion may be an upper beam portion, which within the beam shaping arrangement is first guided away from the forward direction in height direction, and is then guided back toward the forward direction at the light output portion.

For example, this may be achieved by a bridge member included in the beam shaping arrangement, for example a light guide. The bridge member may extend from the light input portion to the light output portion, and may include at least a first bridge member portion directed away from the forward direction into the height direction, and a second bridge member portion directed toward the forward direction in the height direction. In particular, the bridge member may be an arch shaped light guide.

Generally, for the output beam at the light output portion it is preferred that the first, second and any further beam portions are directed to be at least substantially parallel to the forward direction to form an illumination beam.

The illumination beam emitted from the light output portion may preferably be further projected by a projection lens. The projection lens may be used to image the light output portion. The light output portion may be shaped correspondingly, e.g. be of concave shape. At least one front edge of the light output portion may serve to achieve a light/dark boundary in the projected illumination beam. For use in automotive front lighting, at least one laterally extending front edge of the light output portion may include a first and a second edge portion adjacent to each other, which may both be at least substantially straight (or be shaped such that their images projected by a projection lens are at least substantially straight lines). In order to conform to intensity distributions desired for automotive front lighting, the first and second edge portions may be arranged inclined, e.g. at an angle to each other of <NUM>-<NUM>°, preferably <NUM>°.

The beam shaping arrangement may in principal be provided as an arrangement of separate optical elements, such as e.g. one or more collimators, one or more reflector surfaces, etc. The beam shaping arrangement includes a transparent body disposed to guide light from the light input portion in the interior of the body. The body includes reflection surfaces at which light may be reflected due to total internal reflection. As will become apparent in connection with preferred embodiments, the entire beam shaping arrangement may be comprised of a single transparent body. The body includes a central cavity forming reflection surfaces to separate different beam portions. The reflection surfaces are arranged to laterally deflect beam portions into the lateral directions. A light guide may be provided substantially parallel to the forward direction to pass over the cavity.

Generally, it is preferred that the beam shaping arrangement may be of overall flat shape. For example, it may have an extension in lateral direction which is more than twice of an extension in height direction.

These and other aspects of the invention will become apparent from and elucidated with reference to the embodiments described herein after.

<FIG> schematically show a lighting arrangement <NUM> in a top view and side view. The lighting arrangement includes an LED light source <NUM>, a beam shaping arrangement which in the present example is constituted by a solid body <NUM> made out of transparent material acting as a TIR (total internal reflection) body, and a projection lens <NUM>.

The lighting arrangement may be, for example, part of a headlamp of a motor vehicle.

Light emitted from the light emitting surface of the LED light source <NUM> enters the interior of the TIR body <NUM> at a light input surface <NUM> and is internally conducted and guided within the TIR body <NUM> to be emitted at a light output surface <NUM> thereof. As will be further explained below, the light intensity distribution emitted from the light emitting surface of the LED <NUM> as a Lambertian emitter is altered within the TIR body <NUM> such that a shaped illumination beam <NUM> is emitted at the light output surface <NUM> to be projected by the projection lens <NUM>.

While the input beam of light received at the light input surface <NUM> of the TIR body <NUM> corresponds to the square shape of the light emitting surface of the LED <NUM>, the shaped beam <NUM> is laterally widened, i.e. extended into lateral left and right directions as indicated L and R in <FIG>. The height direction H is indicated in <FIG> for reference.

In the schematical example of <FIG>, a forward direction of the beam shaping arrangement may be defined by an optical axis <NUM> through the center of the LED <NUM>, the center of the light input surface <NUM>, the center of the light output surface <NUM> and the center of the projection lens <NUM>. For more detailed embodiments, such as shown in <FIG>, these elements may not be exactly aligned, such that an optical axis may not be easily defined for the whole arrangement. However, a forward direction may still be defined through the center of the light input surface <NUM> and the light output surface <NUM>, e.g. as shown in <FIG>.

The TIR body <NUM>, as shown in <FIG>, is formed in one piece. Three portions arranged one behind the other in the forward direction may be identified, namely an input collimator portion <NUM>, a beam spreading portion <NUM> with a central cavity <NUM>, and a lens adaptation portion <NUM>. A separation of the three portions <NUM>, <NUM>, <NUM> is schematically designated in <FIG> by vertical lines.

Exterior surfaces of the TIR body <NUM> can serve as reflection surfaces for light guided within the TIR body <NUM> if struck by light at an angle below the angle of total reflection. Using this effect, the TIR body <NUM> is shaped to achieve the desired shaped beam <NUM>.

The collimator portion <NUM> is shaped as a cut-off pyramid with substantially square base. The light input surface <NUM> is square and corresponds to the size of the light emitting surface of the LED <NUM>. From the light input surface <NUM>, the input collimator portion <NUM> widens both laterally and vertically in the forward direction.

The lens adaptation portion <NUM> comprises the light output surface <NUM>. In order to adapt to the lens <NUM>, the light output surface <NUM> has concave shape.

The beam spreading portion <NUM> comprises left and right wing portions 50a, 50b to both lateral sides of the central cavity <NUM> and an arch shaped bridge portion <NUM> extending over the cavity <NUM>.

The input beam of light at the light input surface <NUM> is divided into a center beam <NUM>, shown in <FIG> in dashed lines, and left and right peripheral beams <NUM>, shown in dotted lines.

<FIG> shows how the center beam <NUM> and the peripheral beams <NUM> are separated within the TIR body <NUM> in the height direction H. Light portions emitted upward form the central beam <NUM>, whereas light portions emitted substantially horizontally or downward form the peripheral beams <NUM>.

The center beam <NUM> is conducted within the bridge portion <NUM> arranged parallel to the optical axis <NUM> in the center of the beam spreading portion <NUM> of the TIR body <NUM>. The bridge portion <NUM> is an arch shaped light guide for guiding the center beam <NUM> from the input collimator portion <NUM> to a center portion <NUM> of the light output surface <NUM> at the lens adaptation portion <NUM>.

Left and right peripheral beams <NUM> are guided, as shown in <FIG>, within the beam spreading portion <NUM> of the TIR body <NUM> below the bridge portion <NUM>. The cavity <NUM> is formed like a wedge, its front edge being arranged on the optical axis <NUM> and two front surfaces 40a, 40b extending laterally from the front edge under an oblique angle to the optical axis <NUM>. The front surfaces 40a, 40b reflect the peripheral beam <NUM> due to total internal reflection. The peripheral beam <NUM> is separated at the front edge of the cavity <NUM> into left and right peripheral beams reflected to both lateral sides.

Both peripheral beams <NUM> are again reflected at outer surfaces 42a, 42b, of the wing portions 50a, 50b. The surfaces 42a, 42b are also arranged at an oblique angle to the optical axis <NUM> such that, as shown in <FIG>, the peripheral beams <NUM> at the light output surface <NUM> are directed substantially parallel to the optical axis, but pass through laterally peripheral portions 44a, 44b of the light output surface <NUM>.

The resulting shaped beam <NUM> emitted at the light output surface <NUM> is thus composed of the center beam <NUM> emitted at the center portion <NUM> of the light output surface <NUM> and the peripheral beams <NUM> emitted at the laterally peripheral portions 44a, 44b thereof.

The resulting shaped beam <NUM> is thus laterally spread out over the width of the light output surface <NUM>, thus substantially wider, in the example more than <NUM> times, compared to the square light emitting surface of the LED <NUM>. In the height direction H, the resulting shaped beam <NUM> has roughly the same or only slightly larger extension compared to the LED <NUM>.

<FIG> shows a second embodiment of a TIR body <NUM> in a perspective view. Other views of the TIR body <NUM> are shown in <FIG>. The TIR body <NUM> generally corresponds to the TIR body <NUM> according to the first embodiment. Similar or comparable parts thereof will be designated by like reference numerals.

The TIR body <NUM> comprises an input collimator portion <NUM> with a square light input surface <NUM>, and a beam spreading portion <NUM> with wing portions 50a, 50b extending to both lateral sides of the forward direction <NUM>. The beam spreading portion <NUM> includes a central cavity <NUM>. A bridge portion <NUM> is arranged above the central cavity <NUM>. In the example shown in <FIG>, the TIR body <NUM> does not have a specially shaped lens adaptation portion with concave shape. The beam spreading portion <NUM> terminates in a plane light output surface <NUM>.

The beam spreading portion <NUM> includes, arranged on top of the wing portions 50a, 50b, right and left top wing portions 52a, 52b.

The TIR body <NUM> is designed in the same way as the TIR body <NUM> according to the first embodiment to receive light from an LED light source <NUM> at the light input surface <NUM> and shape a laterally spread output beam <NUM> thereof by separating beam portions in height direction and guiding them towards different portions of the light output surface <NUM>.

Exemplary beam paths are shown in <FIG>, including first left peripheral beam <NUM> shown as dotted lines (symmetrical first right peripheral beam not shown for clarity), second right peripheral beam <NUM> shown as slash-double-dotted lines (symmetrical second left peripheral beam not shown for clarity), and a central beam <NUM> shown as a dashed line.

As shown in <FIG>, the central beam <NUM> and the first and second peripheral beams <NUM>, <NUM> follow different beams paths within the TIR body <NUM> separated in the height direction. Light emitted from the light input surface <NUM> into upper directions forms the central beam <NUM> centrally guided along the bridge member <NUM> to the central portion <NUM> of the light output surface <NUM>. Light emitted substantially horizontally forms the left and right first peripheral beams <NUM>, whereas light emitted into lower directions forms the left and right second peripheral beams <NUM>.

The peripheral beams <NUM>, <NUM> are guided within the beam spreading portion <NUM> of the TIR body <NUM> as shown in <FIG>. As in the previously discussed example, the shape of the beam spreading portion <NUM> is laterally symmetrical, so that the peripheral beams <NUM>, <NUM> will divide at the front edge of the cavity <NUM> into left and right beam portions. In order to better illustrate the beam paths, <FIG> shows only the left portion of the first peripheral beam <NUM> and the right portion of the second peripheral beam <NUM>.

The first peripheral beam <NUM> is divided at the front edge of the cavity <NUM> to be reflected at the reflective surfaces 40a, 40b into left and right lateral directions. The thus reflected light of the left and right first peripheral beams <NUM> is then again reflected at outside surfaces 54a, 54b of the top wing portions 52a, 52b of the beam spreading portion <NUM>. After the second reflection, the first peripheral beams <NUM> are again substantially parallel to the forward direction <NUM> and emitted through inner peripheral portions <NUM> of the light output surface <NUM>. The inner peripheral portions <NUM> directly border the central portion <NUM>, such that the shaped beam <NUM> is emitted through the light output surface <NUM> continuously in the lateral directions.

As shown in <FIG>, the second peripheral beams <NUM> are guided within a lower portion of the TIR body <NUM>, such that in the height direction H the first peripheral beams <NUM> are arranged between the center beam <NUM> and the second peripheral beams <NUM>.

The second peripheral beam portions <NUM> are also reflected twice, first at the front surfaces 40a, 40b of the cavity <NUM> and subsequently at side surfaces 42a, 42b of the wing portions 50a, 50b. A thus reflected beam <NUM> is directed substantially parallel to the forward direction <NUM> and emitted through outer peripheral portions <NUM> of the light output surface <NUM>.

The outer peripheral portions <NUM> are arranged laterally further outward relative to the forward direction <NUM>, such that the inner peripheral portions <NUM> are arranged laterally in between the center portion <NUM> and the outer peripheral portions <NUM>.

The light emitted from the LED <NUM> is spread out broadly in both lateral directions. The spread beam <NUM> is composed of contributions from the central beam <NUM> emitted at the center portion <NUM>, the left and right first peripheral beams <NUM> emitted at inner peripheral portions <NUM> of the light emitting surface <NUM>, and the left and right second peripheral beams <NUM> emitted at outer peripheral portions <NUM>. The TIR body <NUM> is shaped such that all of the light output surface <NUM> is illuminated, i.e. the shaped beam <NUM> is continuous in the lateral direction.

As explained, the spread of the beam <NUM> as compared to the light emitting surface of the LED <NUM> is achieved by separating different beam portions in the input collimator <NUM> by their height direction, i.e. by their angle of inclination relative to the forward direction <NUM> and guiding the respective beam portions <NUM>, <NUM>, <NUM> along the described beam paths towards the light output surface <NUM>. As shown in <FIG>, the different beam portions <NUM>, <NUM>, <NUM> converge again in the height direction H towards the light output surface <NUM>. Thus, the output beam <NUM> may have the same height dimension as the light output surface of the LED <NUM>, or may be only slightly larger in the height direction H.

<FIG> shows a third embodiment of the TIR body <NUM>. The TIR body <NUM> corresponds in shape to two of the TIR bodies <NUM> described above arranged side by side. Similar or comparable parts will be designated by like reference numerals.

Each of the halves of TIR body <NUM> comprises an input collimator <NUM> and beam spreading portions <NUM> with wing portions 50a, 50b, top wing portions 52a, 52b, and bridge portions <NUM>. Light output surfaces <NUM> are formed at concave lens adaptation portions <NUM>.

The TIR body <NUM> may be used in a vehicle headlamp with two separate LED light sources arranged in front of the light input surfaces <NUM>. Two separate lenses, or a double lens, may be arranged in front of the light output surfaces <NUM>.

<FIG> shows a longitudinal sectional view of the sectional plane corresponding to the plane A in <FIG>. The relative arrangement of the input collimator <NUM>, the cavity <NUM> with one front surface 40a and the bridge member <NUM> above are shown. As further visible, the lens adaptation portion <NUM> widens in height direction H towards the output surface <NUM>.

<FIG> show sectional view of the sectional planes B, C in <FIG>, showing the shape of the wing portions 50a, 50b and top wing portions 52a, 52b.

The light output surface <NUM> of the TIR body <NUM> is shown in the front view of <FIG>. It is bordered by upper and lower front edges <NUM>, <NUM> extending laterally. The lower edge <NUM> is projected by a projection lens to achieve an illumination beam with a light/dark boundary. In order to conform to regulations, the lower edge <NUM> has a particular asymmetrical shape to achieve a light/dark boundary with a horizontal portion and an inclined portion. At the center of the light output surface <NUM>, the lower edge <NUM> comprises an inclined edge portion 58b adjacent to a substantially horizontal edge portion 58a. In the projected beam, this causes the desired horizontal/inclined light/dark boundary.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing form the scope of the dependent claims.

For example, applying the above described concept of first separating beam portions by height or direction of inclination, and then directing the corresponding beam portions to different lateral portions of a light output surface, a skilled person will be able to propose many different shapes of a TIR body. In particular, the relative dimensions of the light input and light output surface of the TIR body may differ. For example, the height of the light output surface of the TIR body may be even less than the height of the light input surface.

While the described embodiments show symmetrical arrangements, it is also possible to provide laterally non-symmetrical lighting arrangements. The input beam may be divided in the height direction into two, three, or more different beam portions.

Claim 1:
Lighting arrangement including
a light source (<NUM>) with a light emitting surface, and
at least one beam shaping arrangement (<NUM>, <NUM>, <NUM>) including
- a light input portion (<NUM>) for receiving light emitted from said light source (<NUM>), wherein the light input portion (<NUM>) is a light input surface corresponding to the size of the light emitting surface of the light source (<NUM>),
- a light output portion (<NUM>) for emitting a shaped beam (<NUM>), said light output portion (<NUM>) being spaced from said light input portion (<NUM>) and comprising a central output portion (<NUM>) and a peripheral output portion (44a, 44b, <NUM>, <NUM>), the peripheral output portion being laterally outward relative to the central portion (<NUM>), and
- a transparent body including reflection surfaces (40a, 40b, 42a, 42b, 54a, 54b) configured such that light is reflected due to total internal reflection.
wherein a forward direction (<NUM>) is defined from the light input portion into the direction of the light output portion, with the forward direction arranged substantially horizontally,
wherein said beam shaping arrangement (<NUM>, <NUM>, <NUM>) is disposed such that
- light from said light input portion (<NUM>) is divided into at least a first and a second beam portion (<NUM>, <NUM>, <NUM>) separated in a height direction (H) relative to the forward direction,
- said first beam portion is a center beam (<NUM>), which is directed to the central portion (<NUM>) of said light output portion (<NUM>),
- said second beam portion is a peripheral beam (<NUM>), which is relative to the first beam portion directed further outward to the peripheral portion (44a, 44b, <NUM>, <NUM>) of said light output portion (<NUM>), and
- the first and second beam portions (<NUM>, <NUM>) are led to converge in said height direction (H) towards said light output portion (<NUM>),
wherein said transparent body (<NUM>, <NUM>, <NUM>) includes at least one central cavity (<NUM>),
wherein the central cavity (<NUM>) forms reflection surfaces (40a, 40b) to separate the different beam portions (<NUM>, <NUM>, <NUM>) and wherein the reflection surfaces (40a, 40b) are arranged to laterally deflect beam portions (<NUM>, <NUM>) into the lateral directions.