WO2022058425A1

WO2022058425A1 - An illumination system, a lens panel for such illumination system and a method for realizing such lens panel

Info

Publication number: WO2022058425A1
Application number: PCT/EP2021/075481
Authority: WO
Inventors: Andrzej SZYMANIUK
Original assignee: Signify Holding B.V.
Priority date: 2020-09-21
Filing date: 2021-09-16
Publication date: 2022-03-24

Abstract

The invention relates to an illumination system or luminaire suitable but not exclusively for open field lighting applications, such as sports fields, the illumination system comprising a plurality of spatially separated solid state lighting elements, with each solid state lighting element associated with a lens element arranged to shape a luminous distribution around an optical axis of the solid state lighting element. The invention also relates to a lens panel at least composed of a plurality of such lens elements. Furthermore the invention pertains to a method for realizing optic features in such lens panel. The lens panel is provided with optic features configured, during operation of the illumination system, to limit the transmission of visible light emitted by a solid state lighting element in a direction sideways from its optical axis towards the lens element covering a neighboring solid state lighting element. Herewith spill light or spill glare created in the lens panel and which normally exits the illumination system and cause the adverse disturbing side effects outlined above, is significantly reduced.

Description

An illumination system, a lens panel for such illumination system and a method for realizing such lens panel

TECHNICAL FIELD

The invention relates to an illumination system or luminaire suitable but not exclusively for open field lighting applications, such as sports fields, the illumination system comprising a plurality of spatially separated solid state lighting elements, with each solid state lighting element associated with a lens element arranged to shape a luminous distribution around an optical axis of the solid state lighting element. The invention also relates to a lens panel at least composed of a plurality of such lens elements. Furthermore the invention pertains to a method for realizing optic features in such lens panel.

BACKGROUND OF THE INVENTION

Solid state lighting (SSL), e.g. LED lighting, is rapidly gaining popularity because of its energy credentials and superior lifetime compared to traditional lighting, e.g. incandescent lighting, fluorescent lighting and halogen lighting. Nevertheless, market penetration of such SSL devices is not without challenges. For example, a serious challenge is to provide a luminaire including SSL elements that offers the same visual experience as such traditional light sources.

Such challenge is for example found in the field of open field lighting applications, for example the lighting of large areas such as sports fields, where sport events or other venue events, such as music concerts or festivals are held or performed. A major task or challenge of an event lighting system is to illuminate the area in which the event, e.g. a sporting game, is taking place, such, that symmetrical lighting conditions are ensured for optimal sporting conditions.

Additionally, the illumination of the area must create optimal circumstances for high quality (digital) video registration by media outlets, but also must not create nuisance glare for the participants on the field (such as players/officials, etc.) and must not generate any spill light or spill glare to the spectators around the field and surrounding environment. However, in known illumination systems suitable but not exclusively for illuminating sports grounds or fields, the plurality of spatially separated solid state lighting elements act as point sources. With the aid of a lens panel composed of a plurality of lens elements, each interacting with one of these plurality of solid state lighting element, a luminous distribution around the optical axis of each solid state lighting element is shaped, with the overall luminous distribution generated by the whole illumination system being directed towards the large area.

An adverse optical effect of spatially separated solid state lighting elements acting as a point source with a lens element as outlined above is the still noticeable spill glare as each solid state lighting element also emits via neighbouring lens elements. This spill glare is unwanted as it disturbs the illumination of the area both for the spectators as for video registration by media outlets.

Thus, the present disclosure provides an illumination system as well as a lens panel for use in an illumination system, which both provides a solution for the problem of spill light or spill glare outlined above. Additionally, this disclosure aims at providing a method for modifying or adapting lens panels already installed in illumination systems, which lens panels suffer from the problem of spill light or spill glare discussed above.

SUMMARY OF THE INVENTION

According to a first aspect of the disclosure an illumination system is proposed, comprising a support structure, a plurality of spatially separated solid state lighting elements mounted on the support structure for emitting visible light, a lens panel extending over the solid state elements, the lens panel being made from a visible light transmissive material and composed of a plurality of lens elements covering the plurality of solid state lighting elements, and intermediate panel sections interconnecting the plurality of lens elements, wherein each of the plurality of lens elements is arranged to shape a luminous distribution around an optical axis of the associated solid state lighting element, wherein the lens panel is provided with optic features as part of the intermediate panel sections and configured, during operation of the illumination system, to limit the transmission of visible light emitted by a solid state lighting element in a direction sideways from its optical axis towards the lens element covering a neighboring solid state lighting element, wherein the optic features are formed as a cut out element provided in a surface of the intermediate panel section facing away from the support structure to promote the transmission of the in sideways direction emitted visible light in a direction away from the plurality of lens elements towards the support structure, wherein a surface of the support structure facing the lens panel has light absorbing properties.

The lens panel extending over the solid state elements can be obtained for example by the lens panel being disposed or mounted on the support structure over said solid state elements. The plurality of lens elements covering the plurality of solid state lighting elements could be, for example, that each lens element is in optical communication with only a respective one of the solid state elements, or covering only a respective one of the solid state elements, thus forming a plurality of respective pairs of a single lens with a respective single a solid state element.

Herewith spill light or spill glare created in the lens panel and which normally exits the illumination system and cause the adverse disturbing side effects outlined above, is significantly reduced. This results in an illumination system with an improved luminous distribution for all, including persons within the area to be illuminated (players, officials, artists), spectators around the area to be illuminated and media outlets recording the event for video registration.

In a particular, the optic features are configured to promote the transmission of the in sideways direction emitted visible light in a direction away from the plurality of lens elements. This completely limits any spill light or spill glare from exiting or escaping the illumination system.

Furthermore, the optic features are part of the intermediate panel sections. Therefor the main optic functionality of the lens elements, that is providing the luminous distribution around the optical axis of the associated solid state lighting element towards the area to be illuminated, is not adversely affected, in fact its optic functionality is upheld thus the main illumination functionality of the illumination system is not compromised.

Furthermore, the optic features are formed as a cut out element provided in a surface of the intermediate panel section facing away from the support structure. Providing such cut out element is even possible in existing lens panels, allowing the modification of illumination systems already installed in open field lighting applications.

In an example of the disclosure, the cut out element has an inclined cut out surface, which inclined towards the support structure seen from the surface of the intermediate panel section facing away from the support structure, thus ensuring a limited transmission of visible light emitted by a solid state lighting element in a direction sideways from its optical axis and more in particular ensuring the transmission of light in a direction away from the lens elements thus limiting spill light or spill glare from exiting or escaping the illumination system.

In order to further ensure that spill light or spill glare does not escape the illumination system towards the area to be illuminated by the main luminous distribution the inclined cut out surface is optically structured. In particular, the inclined cut out surface exhibits a surface roughness with a Ra < 0.01pm.

In an example which limits the transmission of visible light emitted by a solid state lighting element in a direction sideways from its optical axis towards the lens element covering a neighboring solid state lighting element and/or promote the transmission of the in sideways direction emitted visible light in a direction away from the plurality of lens elements, the cut out element has an apex angle in the range of 25° to 35°, in particular an apex angle of 30°.

To further limit any exiting or escaping of spill light or spill glare from the construction of the illumination system, a surface of the support structure facing the lens panel has light absorbing properties.

In an example, the surface of the support structure facing the lens panel is at least locally blackened, in particular at the locations where the lens panel contacts the support structure.

Another example of the disclosure, further limiting the exit or escaping of spill light or spill glare from the construction of the illumination system, a light absorbing component is mounted between the support structure and the lens panel.

Additionally, the illumination system may comprise a plurality of visible light shielding elements mounted on the intermediate panel sections of the lens panel in order to control the overall luminous distribution of the illumination system.

The invention also pertains to a lens panel for use in an illumination system according to the disclosure.

Furthermore a method for realizing optic features in a lens panel is proposed, which lens panel is used in an illumination system according to the disclosure. In particular the illumination system comprises a support structure, a plurality of spatially separated solid state lighting elements mounted on the support structure for emitting visible light, said lens panel disposed on the support structure, wherein the lens panel is made from a visible light transmissive material and composed of a plurality of lens elements covering the plurality of solid state lighting elements and intermediate panel sections interconnecting the plurality of lens elements, wherein each of the plurality of lens elements is arranged to shape a luminous distribution around an optical axis of the associated solid state lighting element.

And the method according to the disclosure comprises the step of receiving, by said lens panel, a tool for realizing in the lens panel optic features, such that, during operation of the illumination system, to limit the transmission of visible light emitted by a solid state lighting element in a direction sideways from its optical axis towards the lens element covering a neighboring solid state lighting element.

With the method according to the disclosure it is possible to modify or adapt lens panels which already installed in illumination systems, ands which lens panels suffer from the problem of spill light or spill glare as discussed above.

In particular, the step of realizing the optic features in the lens panel comprises the step of removing, using the tool, material of the lens panel from of a surface of the intermediate panel section facing away from the support structure thus forming a cut out element according to the disclosure. Alternatively, the optic features in the lens panel can be obtained by deformation, for example via a molding step or via a, facultatively local, heating and an embossing step.

In particular, in an example the method also involves the step of optically structuring the inclined cut out surface of the cut out element.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be discussed with reference to the drawings, which show in:

Figs, la and lb a top and side view respectively, of an example of known illumination systems used but not exclusively for illuminating a sports pitch;

Figs. 2a and 2b an example of a known illumination system in more detail;

Figure 3 a side view of a known illumination system with a luminous distribution around an optical axis.

Fig. 4 detailed view of an example of an illumination system according to the disclosure;

Figs. 5a-5c detailed views of other examples of an illumination system according to the disclosure;

Figs. 6a and 6b details of a lens element of a lens panel according to the disclosure; Fig. 7 a detail of a further example of a lens panel according to the disclosure; and

Fig. 8 exemplifying the providing of an optic feature in a lens panel.

DETAILED DESCRIPTION OF THE INVENTION

For a proper understanding of the invention, in the detailed description below corresponding elements or parts of the invention will be denoted with identical reference numerals in the drawings.

A major task or challenge of an event lighting system is to illuminate the area in which the event, e.g. a sporting game, is taking place, such, that symmetrical lighting conditions are ensured for optimal sporting conditions. An example of an open field lighting application, for example the lighting of large areas such as sports fields, where sport events or other venue events, such as music concerts or festivals are to be held or to be performed is shown in Figures la and lb.

Reference numeral 1 depicts an open field, in particular a sports field, more in particular a football or field hockey terrain. At each corner of the field 1 a known illumination system is positioned, in particular mounted on top of a post 100, see Figure lb.

It is known in the prior art that in known illumination systems 10 suitable but not exclusively for illuminating sports grounds or fields 1, the plurality of spatially separated solid state lighting elements act as point sources. With the aid of a lens panel composed of a plurality of lens elements, each interacting with one of these plurality of solid state lighting element, a luminous distribution around the optical axis of each solid state lighting element is shaped, with the overall luminous distribution generated by the whole illumination system being directed towards the large area.

An example of such known illumination system is depicted in Figure 2a and 2b and in detail in for example Figure 3. The illumination system 10 in general is composed of a housing (not depicted). The illumination system 10 further comprises a support structure 11 and a plurality of N spatially separated solid state lighting elements 30 mounted on the support structure 11. For example, the plurality of N spatially separated solid state lighting elements 30 are mounted on the support structure 11 in an array of rows and columns. When powered or activated, the plurality of spatially separated solid state lighting elements 30 emit visible light.

The support structure 11 may be part of a housing (not depicted) of the illumination system 10. The support structure 11 may contain or comprise electric circuitry and electric components for providing electric power to the several components of the illumination system 10, in particular the spatially separated solid state lighting elements 30, which are mechanically and electrically mounted to the upper surface 1 la of the support structure 11. The support structure 11 can be composed entirely or partly as a printed circuit board (PCB).

A lens panel 20 is disposed on the support structure 11. Predominantly, the lens panel 20 has a plate shaped configuration, meaning that its longitudinal dimensions (length and width) are significantly larger than its thickness. The lens panel 20 is made from a visible light transmissive material, such as polycarbonate, PMMA, silicone, glass, etc. The lens panel 20 is composed of a plurality of N lens elements 21 and intermediate panel sections 23, which intermediate panel sections 23 interconnect the plurality of N lens elements 21. Therefor the lens panel 20 forms one single element, allowing an easy and practical mounting and unmounting from the illumination system 10.

The plurality of N lens elements 21 are arranged in a similar array configuration as the array of N solid state lighting elements 30. Thus, when mounted to the support structure 11 of the illumination system 10 the plurality of N lens elements 21 of the lens panel 20 each cover one of the plurality of N solid state lighting elements.

The number of spatially separated solid state lighting elements 30 / lens elements 21 can be 1 or 2, but preferably at least 2. Suitable examples of an illumination system 10 for example for use in illuminating an open (sports) field may comprise 10 or more, even 20, 30+ per illumination system 10 depending on the size and application of the illumination system.

As shown in Figure 3, the lens panel 20 has a first panel surface 23a and a second panel surface 23b, each arranged opposite from each other. The second panel surface 23b faces the upper surface 1 la of the support structure 11 and contacts the upper surface I la in the mounting condition of the lens panel 20.

As shown in Figure 3, each lens element 21 has a thickened material portion compared to the intermediate panel sections 23. In particular each lens element 21 is shaped as a concave lens with its concave light exit surface 21a at the first panel surface 23a and directed towards the exterior of the illumination system 10. At the second panel surface 23b the lens panel 20 is provided with cavities. Each cavity 22 has a specifically shaped cavity surface 22b, which forms the light entry surface 22b of the associated lens element 21. When in the mounting position of the lens panel 20 on the support structure 11, the cavity 22 covers or accommodates a solid state lighting element 30 mounted on the support structure 11. As depicted in Figure 3, each solid state lighting element 30ⁿ, cavity 22ⁿ, and lens element 21ⁿ (with n e {0, 1, 2, 3, N}) form an optical system for the transmission of visible light emitted by the respective solid state lighting element 30. In particular, each of the plurality of N lens elements 21ⁿ emit primary light 3 lⁿ based on light being emitted by the respective solid state lighting element 30ⁿ. Due to its optical characteristic each lens element 21ⁿ shape the primary light being emitted in a luminous light distribution 3 lⁿ around the optical axis 30a of the associated solid state lighting element 30ⁿ. Said individual luminous light distribution 3 lⁿ of each solid state lighting element 30ⁿ and exiting the concave exit surface 21a of the associated lens element 21ⁿ are part of the full luminous light distribution 31 generated by all solid state lighting elements 30 of the whole illumination system 10 as depicted in Figure la.

Optionally, as shown in Figures 2b and 3, the illumination system 10 may be provided with shielding elements 40, also known as louvers, disposed on the lens panel 20 between adjacent rows of solid state light emitting elements 30 / lens elements 21. The louvers 40 function as collimators, limiting excessive dispersion or scattering of the primary light exiting the lens element 21ⁿ and directing the individual luminous light distribution 3 lⁿ towards the area to be illuminated.

In the example of Figure la, the full luminous distribution generated by each illumination system 10 positioned at a corner of the field 1 and being directed towards the sports field 1 is denoted with reference numeral 31. The overall combined luminous distributions 31 of the four illumination systems 10 illuminating the field 1 preferably provides a symmetrical lighting coverage, thus ensuring optimal sporting conditions, and optimal circumstances for high quality (digital) video registration by media outlets.

Preferably, the illumination of the field 1 must also not create nuisance glare for the participants on the field 1 (such as players/officials, etc.) and must not generate any spill light or spill glare to the spectators around the field 1 and surrounding environment.

However, an adverse optical effect of spatially separated solid state lighting elements 30 acting as a point light source with a lens element 21ⁿ is the still noticeable secondary light or spill glare indicated with reference numeral 32. Each solid state lighting element 30ⁿ, for example solid state lighting element 30¹ in Figure 3, acts as a point light source and also emits visible light in a sideway direction away from its optical axis 30a. Such visible secondary light 32 exits the associated cavity 22ⁿ in a sideway direction via the cavity side surface 22a, and propagates through the intermediate panel section 23¹ towards its neighbouring lens element 21°. In particular, and as shown in Figure 3 this sideways emitted secondary light 32 is internally reflected in the lens panel material via the first panel surface 23a and the cavity surface 22b of the neighbouring cavity 22° and exits the neighbouring lens element 21° as spill glare light 32¹. This spill glare light 32¹ is unwanted as it disturbs the illumination of the area both for the spectators as for video registration by media outlets.

To obviate these unwanted optical effects in the illumination system 10 according to the prior art, in this disclosure it is proposed to provide the lens panel with optic features, which optical features are configured, during operation of the illumination system, to limit the transmission of visible light emitted by a solid state lighting element in a direction sideways from its optical axis 30a towards the lens element covering a neighboring solid state lighting element.

An example of such illumination system 10’ according to the disclosure provided with a lens panel 20’ according to the disclosure is shown in Figure 4. The optic features provided in the lens panel 20’ according to an example of the disclosure are denoted with reference numeral 25¹ (25ⁿ) and configured to limit the transmission of visible light emitted by a solid state lighting element 30ⁿ in a direction sideways from its optical axis 30a towards the lens element 21° (21 "" ¹ ) covering a neighboring solid state lighting element 30° (30^n-1). In particular and as shown in Figure 4, the optic features 25¹ (25ⁿ) promote the transmission of the in sideways direction emitted visible secondary light in a direction away from the plurality of lens elements 21ⁿ of the lens panel 20’ according to the disclosure.

This secondary light emitted by a solid state lighting element 30ⁿ and being transmitted via the optic features 25ⁿ in a direction away from the plurality of lens elements 21ⁿ is denoted with reference numeral 32¹ (32ⁿ) and in particular this secondary light 32ⁿ is being directed towards the support structure 11.

In particular, the optic features 25ⁿ are part of or present in the intermediate panel sections 23ⁿ between two adjacent lens elements 21^n-1 and 21ⁿ of the lens panel 20’. Furthermore, in an advantageous example of both a lens panel 20’ and an illumination system 10’ according to the disclosure, the optic features 25ⁿ are formed as a cut out element provided in the first panel surface 23a of the intermediate panel section 23ⁿ, which first panel surface 23 a faces away from the support structure 11.

Depicted in more detail in an example of a lens panel 20’ and an illumination system 10’ according to the disclosure in Figures 6a and 6b combined with Figure 7, the cut out element 25ⁿ has an inclined cut out surface 25a, which is inclined towards the support structure 11 seen from the first panel surface 23a of the intermediate panel section 23ⁿ facing away from the support structure 11. As depicted in Figure 6a and 6b the cut out element 25ⁿ has the shape of a cut out prism having a longitudinal direction L more or less equal to the width W of the cavity 22 of the associated lens element 21ⁿ.

Herewith it is ascertained that any spill light 32 emitted in a sideway direction by the solid state lens element 30 accommodated in the cavity 22 will impinge on the inclined cut out surface 25a of the cut out surface 25 and subsequently be transmitted in a direction away from the (neighboring) lens elements 21 of the lens panel 20’, and preferably towards the support structure 11 and does not ‘escape’ from the cavity 22 in an unwanted direction causing unwanted spill light glare 32.

In an example, the cut out element 25ⁿ has an apex angle a between the inclined cut out surface 25a and the first panel surface 23a, which apex angle a in the range of 25° to 35°, and in particular an apex angle a of 30°.

The apex angle a in the ranges as defined above limits the transmission of visible secondary light emitted by a solid state lighting element 30ⁿ in a direction sideways from its optical axis 30a towards the lens element 21""' covering a neighboring solid state lighting element 30"'¹. Instead it promotes the transmission of the in sideways direction emitted visible secondary light in a direction away from the plurality of lens elements 21ⁿ of the lens panel 20’, as stipulated above.

Preferably, in order to further enhance the reflection of the in sideways direction emitted visible secondary spill light 32ⁿ in a direction away from the plurality of lens elements 21ⁿ, the inclined cut out surface 25a is optically structured. In an example according to the disclosure, the inclined cut out surface 25a has a surface roughness with Ra < 0.01pm (arithmetical mean deviation of the assessed profile of the inclined cut out surface 25a). In particular, the optically structured inclined cut out surface 25a is obtained by means of a mirror polishing technique.

The optic features in the lens panel 20’ according to the disclosure, in particular the cut out element 25ⁿ achieve an optimal total internal reflection (T.I.R.) provided that the cut out element 25ⁿ exhibit the correct dimensions. As outlined, the apex angle a between the inclined cut out surface 25a and the first panel surface 23a is in the range of 25° to 35°, and in particular a is about or is 30°. In addition, another important dimension is the minimum angle 0 which is needed in order to achieve TIR (total internal reflection) of the secondary light 32ⁿ emitted by the solid state lighting element 30ⁿ via the optic features 25ⁿ in a direction away from the plurality of lens elements 21ⁿ and in particular in the direction of the support structure 11 as depicted in Figures 4, 5a-5c and 7. The angle 0 for achieving TIR is different for different materials used as the light transmissive material for the lens panel 20’ and is defined according to the equation:

9 = arc sin ( / ) with, ni the refractive index of medium 1 (here the lens panel 20’, e.g. manufactured from polycarbonate: m = 1.586) n2 the refraction index of medium 2 (normally air: = 1)

For the example of the lens panel 20’ being made from polycarbonate the angle 9TIR for achieving TIR is approx. 39.1°. The lens panel can also be manufactured from other light transmissive materials, such as (poly)methyl methacrylate (PMMA) having a refractive index of = 1.49 resulting in an angle 9TIR of 42.15°.

As depicted in the Figures, the cut out element 25ⁿ has next to the inclined cut out surface 25a also a base cut out surface 25b.

The optic features formed as the cut out element 25ⁿ in the first, upper panel surface 23a of the lens panel 20’ as shown in the examples of Figures 4, 5a-5c, 6a-6b and 7 will, by means of total internal reflection, transmit any secondary light 32ⁿ emitted by the solid state lighting element 30ⁿ and propagating through the intermediate panel section 23ⁿ towards the neighboring lens element 21""' in a direction away from the plurality of lens elements 21ⁿ and in particular towards the support structure 11.

The illumination system 10’ according to the disclosure will only emit as depicted in Figure 7 a luminous light distribution 3 lⁿ around the optical axis 30a, whereas any adverse spill light glare 32ⁿ, which occurs with an illumination system known in the art (Figures 1-3), is absent.

In yet another advantageous example of an illumination system 10’ according to the disclosure a surface of the support structure 11 facing the lens panel 20’ has light absorbing properties. An example of this feature is shown in Figure 5b wherein the (upper) surface of the support structure 11 facing the lens panel 20’ is at least locally blackened. This local blackening is depicted by reference numerals I la and is provided on those parts of the upper surface of the support structure 11 directly contacting the lens panel 20’. More in particular the local blackening is present on those parts of the upper surface of the support structure 11 directly contacting the second panel surface 23b of the intermediate panel sections 23ⁿ of the lens panel 20’.

In Figure 5a the blackening 1 la is provided on the overall upper surface of the support structure 11, also locally of the solid state lighting elements 30ⁿ and the cavities 22ⁿ. In Figure 5c yet another advantageous example of an illumination system 10’ of the disclosure is depicted, wherein a separate light absorbing component 12 is mounted between the support structure 11 and the lens panel 20’. The component 12 should be made from a light absorbing material, and preferably have dielectric characteristics. As to the thickness of the component 12 it is noted that may not obstruct the light emission functionality of the solid state lighting elements 30. Thus the thickness of the component 12 should be smaller than height of the solid state lighting elements 30 mounted on the support structure 11, measured from bottom part of solid state lighting elements 30 to its optical center.

The disclosure also relates to a method for realizing optic features 25 in a lens panel 20 used in an illumination system 10. In particular the method according to the disclosure allow modifying lens panels 20 already mounted in existing illumination systems 10 as for example disclosed in Figures 1-3.

An example of a method step being performed on such lens panel is shown in Figure 8. Similarly, the lens panel 20 on which the method for realizing optic features in is performed, is made from a visible light transmissive material and composed of a plurality of lens elements 21, which when mounted in an illumination system 10 cover the plurality of solid state lighting elements 30. Also such lens panel 20 comprises intermediate panel sections 23 interconnecting the plurality of lens elements 21.

The method according to the disclosure comprises the step of receiving, by said lens panel 20, a tool 50 for realizing in the lens panel 20 the optic features 25 as described in this disclosure, that is realizing optic features 25 having the optic functionality as to limiting the transmission of visible light emitted by a solid state lighting element 30ⁿ in a direction sideways from its optical axis 30a towards the lens element covering a neighboring solid state lighting element 30"'¹.

In particular, the method as disclosed in Figure 8 comprises the step of removing, using the tool 50, material (indicated with reference numeral 250) of the lens panel 20 from the first panel surface 23 a of the intermediate panel section 23 facing away from the support structure 11. Alternatively, this could be attained via a molding or an embossing step. The tool 50 is provided with a tool tip 50a configured to form the cut out element 25 as described in this disclosure, for example the prism-shaped cut out element 25.

Additionally, to improve the total internal reflection (T.I.R.) of the cut out element 25 thus formed, the method implements the further step of optically structuring the inclined cut out surface 25a of the cut out element 25. In an example of the method according to the disclosure the step of optically structuring comprises the step of mirror polishing. Preferably, the step of optically structuring results in the inclined cut out surface 25a having a surface roughness with Ra < 0.01 pm (arithmetical mean deviation of the assessed profile of the inclined cut out surface 25a).

Claims

CLAIMS:

1. An illumination system comprising: a support structure, a plurality of spatially separated solid state lighting elements mounted on the support structure for emitting visible light, a lens panel extending over the solid state lighting elements, the lens panel being made from a visible light transmissive material and composed of:

- a plurality of lens elements covering the plurality of solid state lighting elements, and

- intermediate panel sections interconnecting the plurality of lens elements, wherein each of the plurality of lens elements is arranged to shape a luminous distribution around an optical axis of the associated solid state lighting element, the lens panel is provided with optic features as part of the intermediate panel sections and configured, during operation of the illumination system, to limit the transmission of visible light emitted by a solid state lighting element in a direction sideways from its optical axis towards the lens element covering a neighboring solid state lighting element, wherein the optic features are formed as a cut out element provided in a surface of the intermediate panel section facing away from the support structure to promote the transmission of the in sideways direction emitted visible light in a direction away from the plurality of lens elements towards the support structure, wherein a surface of the support structure facing the lens panel has light absorbing properties.

2. The illumination system according to claim 1, wherein the cut out element has an inclined cut out surface, which inclined towards the support structure seen from the surface of the intermediate panel section facing away from the support structure.

3. The illumination system according to claim 2, wherein the inclined cut out surface is optically structured.

4. The illumination system according to any one or more of the preceding claims, wherein the cut out element has an apex angle in the range of 25° to 35°, in particular an apex angle of 30°.

5. The illumination system according to any one or more of the preceding claims, wherein the surface of the support structure facing the lens panel is at least locally blackened.

6. The illumination system according to any one or more of the preceding claims, wherein a light absorbing component is mounted between the support structure and the lens panel.

7. The illumination system according to any one or more of the preceding claims, further comprising a plurality of visible light shielding elements mounted on the intermediate panel sections of the lens panel.

8. A lens panel for use in an illumination system as defined in any one or more of the claims 1-4.

9. A method for realizing optic features in a lens panel used in an illumination system, wherein the illumination system comprises a support structure, a plurality of spatially separated solid state lighting elements mounted on the support structure for emitting visible light, said lens panel disposed on the support structure, wherein the lens panel is made from a visible light transmissive material and composed of a plurality of lens elements covering the plurality of solid state lighting elements and intermediate panel sections interconnecting the plurality of lens elements, wherein each of the plurality of lens elements is arranged to shape a luminous distribution around an optical axis of the associated solid state lighting element, wherein the method comprises the step of: receiving, by said lens panel, a tool for realizing in the lens panel optic features, such that, during operation of the illumination system, to limit the transmission of visible light emitted by a solid state lighting element in a direction sideways from its optical axis towards the lens element covering a neighboring solid state lighting element, removing, using the tool, material of the lens panel from of a surface of the intermediate panel section facing away from the support structure thus forming a cut out 16 element to promote the transmission of the in sideways direction emitted visible light in a direction away from the plurality of lens elements towards the support structure.

10. The method of claim 9, further comprising the step of optically structuring the inclined cut out surface of the cut out element.