WO2013111032A1

WO2013111032A1 - Lighting system and a luminaire

Info

Publication number: WO2013111032A1
Application number: PCT/IB2013/050323
Authority: WO
Inventors: Stephan Certain
Original assignee: Koninklijke Philips N.V.
Priority date: 2012-01-24
Filing date: 2013-01-14
Publication date: 2013-08-01

Abstract

A lighting system (100) and a luminaire are provided. The lighting system (100) lightens the area (122) and projects a pattern (120) on the area (122). The lighting system (100) comprises a pattern device (104), a light source assembly (110) and a projection lens device (106). The pattern device (104) is of a material being at least partially transparent. The pattern device (104) comprises a plurality of light-shaping patterns (102) according to a determined spatial arrangement. The light source assembly (110) comprises a plurality of light sources (116). Each light source (116) provides a light beam (118). The projection lens device (106) is arranged to receive light from the light source assembly (110) via the pattern device (104) and is configured to refract the light beams (118) to lighting the area (122) and to project an image of the light-shaping patterns (102) in the area (122). The projection lens device (106) comprises a plurality of projection lenses (108) arranged according to the spatial arrangement. The focal planes of the plurality of projection lenses (108) at least partially coincide with the pattern device (104).

Description

LIGHTING SYSTEM AND A LUMINAIRE

FIELD OF THE INVENTION

The invention relates to lighting systems which additionally projects a pattern.

BACKGROUND OF THE INVENTION

Existing projection systems, such as, for example, gobos, emit in general a relatively narrow collimated light beam which projects a pattern on the target area. The existing projection system relies on a strong contrast in luminance by starting from a dark background and having luminance peaks associated with the pattern. Such narrow collimated light beams and/or luminance peaks are not suitable for comfortably lightening an area.

Such a projection system is, for example, known from WO2011027254. The document discloses a picture projector. The picture projector comprises a light source emitting a parallel light beam, a first lens array dividing the parallel light beam into a plurality of unitary beams, a diaphragm comprising a plurality of holes through which unitary beams go through, a translucent screen comprising a plurality of optical elements wherein the optical elements receive unitary beams to form images of optical elements, a second lens array projecting the images of the optical elements so as to form one picture onto a projection screen. The projection system is designed to project images, such as company logos, and the diaphragms are used to transmit an amount of light which is just enough light to make the projected image visible. Thus, the picture projection system is not suitable for lighting an area.

When, for example, an outdoor area is to be lightened, substantially the whole area should receive a relatively high amount light for safety and comfort. The projection of a pattern in such a lightened outdoor area may be decorative such that the area looks more attractive in the dark.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a lighting system which comfortably lightens an area and at the same time projects a pattern in the lightened area.

A first aspect of the invention provides a lighting system. A second aspect of the invention provides a luminaire. Advantageous embodiments are defined in the dependent claims. A lighting system in accordance with the first aspect of the invention illuminates an area and projects a pattern on the area. The lighting system comprises a pattern device and a light source assembly. The pattern device is of a material being at least partially transparent. The pattern device comprises a plurality of at least partially light shaping, i.e. light-blocking or light-diffusive, patterns according to a determined spatial arrangement. The light source assembly comprises a plurality of light sources according to the determined spatial arrangement. Each light source provides a light beam. During operation the lighting system the light source is to issue the light beams via the pattern device to lighten an area for projecting, within an originally dedicated lighting functionality of the system, an image pattern of the at least partially light shaping patterns in the area.

Alternatively, the lighting system further comprises a projection lens device. The projection lens device comprises a plurality of projection lenses arranged according to the spatial arrangement. The focal planes of the plurality of projection lenses at least partially coincide with the pattern device. In this alternative embodiment the projection lens device is arranged to receive light from the light source assembly via the pattern device and is configured to refract the light beams to lighting the area and to project an image pattern of the at least partially light-shaping patterns in the area.

The lighting system comprising the projection lens device has the advantage that a generally sharper image pattern is projected in the area than is projected in said area with the lighting system without the projection lens device. On the other hand, with the lighting system without the projection lens device a significant cost reduction of the lighting system is obtained compared to the lighting system comprising the projection lens device, and. Yet, from the perspective of the intended application of the lighting system, in practice image patterns of acceptable sharpness were obtained with the lighting system without the projection lens device. Furthermore, the system without the projection lens device has the advantages that generally a relatively large cone angle of image is projected in the area which fit real lighting application, and that it does not suffer from a problem of aberration which potentially could occur with the lighting system comprising said projection lens device.

As a general remark: everywhere in the description where the lighting system with the projection lens device is mentioned, described or discussed, a same reasoning applies mutatis mutandis to the lighting system without said projection lens device.

In the lighting system the light of the plurality of light sources is refracted to the area to be lightened, and, thus, the area is well lightened. The pattern device which is arranged in between the light source assembly and the projection lens device locally block portions of the light according to the patterns. Because the focal planes of the projection lenses coincide at least partly with the pattern device, the patterns are projected by the projection lenses onto the area. The projected patterns are superposed on the area because the light sources, because they are arranged to the spatial arrangement, which means that about each at least partially light-shaping pattern is related to a single projection lens and that the at least partially light-shaping pattern and the single projection lens are arranged in an equal spatial arrangement.

The patterns locally reduce the amount of light that is transmitted through the pattern device, and, consequently, the patterns are projected as locally less intense lightened regions of the area. Thus, most of the area is lightened which is experienced as comfortable lighting, and at the same moment a pattern is visible as a decorative effect. The pattern may also comprise information, like directional information, or an advertisement of a company logo.

Further, the lighting system may be manufactured relatively compact. The light sources may be relatively small, the pattern device may be arranged at a relatively short distance from the light sources and at a relatively short distance from the projection lens device.

The pattern device may, for example, be a layer of a transparent material on which the patterns are printed. An example is a layer of glass on which at one of its surfaces the patterns are provided with ink or with metal track. The focal planes of the projection lenses coincide with the surface on which the patterns are provided. The pattern device may also be a transparent sheet on which the patterns are printed. The patterns are at least partially light blocking or light-diffusive. When the patterns are at least partly light-blocking this means that the pattern may comprises black lines or black pixels which locally fully block the transmission of light, or the lines or pixels are partially light transmitting such that, for example, a smaller amount of light is transmitted along the whole light emission spectrum of the light sources, or that a portion of the light emission spectrum of the light sources is locally blocked.

Optionally, the at least partially light-shaping patterns extend over a pattern surface. The light sources are arranged over a light surface parallel to the pattern surface and/or the projection lenses are arranged over a lens surface parallel to the pattern surface. The parallel arrangements according to this optional embodiment contribute to a good alignment of the light sources with respect to the at least partially light-shaping patterns, and/or the projection lenses. Optionally, the (at least partially) light-shaping patterns are arranged according to regular pitches and the projection lenses are arranged according to similar regular pitches. Thus, the spatial arrangement of the (at least partially) light-shaping patterns results in equal distances between the neighboring light-shaping patterns and between projection lenses.

Optionally, the light sources are arranged according to similar regular pitches.

Optionally, the number of the at least partially light-shaping patterns is equal or greater than the number of projection lenses.

Optionally, the number of at least partially shaping patterns is equal to or larger than the number of light sources, and/or the number of projection lenses is equal to or larger than the number of the light sources. According to this optional embodiment, all light of the light sources is used for lighting and at least partially shaping pattern and/or for being refracted to the area to be lightened and for projecting the pattern.

Optionally, the light beams emitted by the plurality of light sources have all substantially the same shape and/or have all substantially the same direction. If all light beams are emitted in substantially the same direction and/or have substantially the same shape, the projection lens device may be less complex by using less complex lenses which are, in an embodiment, equal to each other.

Optionally, each the light source forms a sub-lighting system together with a nearest at least partially light-shaping pattern on the pattern device and a nearest project lens of the projection lens device. A sub-optical axis of a sub-lighting system is defined from a line passing through respectively a center of the light source, a reference point of the at least partially light-shaping pattern and a center of the projection lens. The light source assembly, the pattern device and the projection lens device are arranged such that at least a part of the sub-optical axes are parallel to each other.

This means that the light source assembly, the pattern device and the projection lens device are well aligned with respect to each other and that light, which is emitted by the light source, is received by the nearest pattern and is subsequently received by the nearest projection lens. Further, the projection lens of a specific sub-lighting system projects the pattern of the specific sub-lighting system. Furthermore, all lines through centers of entities of the sub-lighting system are at least partially parallel, which means that all patterns are projected in a well-aligned manner; the projected patterns are superposed.

The reference point of the pattern may be the center of the pattern. If the pattern is a non-centered pattern, the reference point is a point of the pattern which forms after projection a center point of the area to be lightened. Thus, the reference point of the pattern is a projected center point of the area to be lightened projected by the nearest projection lens onto the pattern device.

Optionally, an optical axis of each projection lens coincides with the optical axis of the nearest light source, and the optical axis of each projection lens interferes with the nearest pattern in a reference point of the nearest pattern.

Optionally, the lighting system comprises the area on which the pattern is projected. A ratio is defined as the ratio between the mean distance between the at least partially light-shaping patterns and a projection distance between the projection lens device and the area. The ratio is sufficiently small to obtain a relatively sharply projected pattern.

The projection distance is a distance between the lighting system and the area on which the pattern is projected. The projection distance may be measured from the surface of the projection lens device which faces to the area along the shortest line from the lighting system to the area.

This means that, to prevent blur in the superposed projected patterns, the Gauss conditions must be fulfilled - if the Gauss conditions are fulfilled, the projected pattern is not blurry. Thus, if the plurality of patterns are equal to each other, they are projected on top of each other on the area (they are superposed) and the edges of the projected pattern are sharp in the superposed projected pattern. The Gauss conditions are fulfilled for projection a relatively sharp image when the light rays, which enter the projection lens(es), have a relatively low angle with respect to the optical axis of the projection lens(es). An angle is relatively low when the angle is smaller than 25°, and in another embodiment the relatively low angle is smaller than 15°.

It is to be noted that this optional embodiment prevents blur in the pattern, however, because of projection physics there will always be a limited amount of blur at the edges of the projected pattern. The projection lens device of the invention is not complex, which may result in the limited amount of blur at the edges of the projected pattern. In the lighting system a design choice is made to obtain a relatively cheap and not complex lighting system. The skilled person may increase the complexity of the lighting system to obtain a more sharply projected pattern. The skilled person may, for example, use more accurate projection lenses, or combine a plurality of lenses to form a single projection lens.

It is to be noted that, in order to make the lighting system less complex, the Gauss conditions may be relaxed to some extend to voluntarily introduce a limited amount of blur. The lighting system according to the invention has to project at least a suggestion of the patterns of the pattern device to create a more pleasantly lightened area. A projected pattern with a relatively small amount of blur may already result in a pleasantly lightened area.

Optionally, the ratio is equal to, or smaller than, 1/100. If the condition of this optional embodiment is fulfilled in use, Gauss conditions are fulfilled and the patterns are well superposed and sharply projected.

Optionally, the at least partially light shaping patterns of the pattern device are filters or pictures similar to each other. Thus, the pattern is projected several times by superposition and, thus, is the pattern well visible. The pattern is well visible as the result of a relatively high contrast between the lightened portions of the area and the portions of the area forming the pattern.

Optionally, only light shaping patterns of a subset of the plurality of at least partially light shaping patterns are similar to each other. Optionally, the plurality of at least partially light shaping patterns is different from each other. If not all the patterns are equal to each other, the combination of the projected patterns forms the finally projected pattern, and the projected pattern has less contrast with respect to the lightened portions of the lightened area. This allows the creation of a pattern with different intensity levels (and/or different colors). For example, if a specific part of the projected pattern needs to have half of the maximum intensity level of the portions that are fully lightened, only half of the plurality of patterns of the need to have the light shaping feature resulting which results in this specific projected part.

Optionally, the projection lenses comprise poly methyl methacrylate (PMMA). An intrinsic effect of the lighting system is that the presence chromatism at the boundary of each projected pattern due to the dependency of the refractive index of the projection lens material with the wavelength of light. It is noted that this effect may be advantageously used or may be considered as a disadvantage. The effect results in a colored irisation of the boundaries. If it is considered to be disadvantage, the use of PMMA as a material for the projection lenses limits the chromatism effect. The projection lenses may also be made of other materials, such as glass or other transparent polymeric material (e.g. Polycarbonate).

Optionally, the pattern device is a sheet of material interchangeable in the lighting system for allowing the replacement of the pattern device. Thus, if the pattern device can be changed, the lighting system can be modified to project another pattern which is user- friendly.

Optionally, the projection lens device comprises a molded flat base and the projection lenses protrude from a face of the flat base which faces toward the area on which the pattern is to be projected. The projection lenses are made as an integrated part of the fiat base, or are fixed to the fiat base. The flat base is arranged in contact with the pattern device and is sufficiently thick to obtain a predefined distance between the pattern device and the projection lenses. In the optional embodiment there is no air-gap between the projection lens device and the pattern device which is advantageous because refraction is prevented at the interfaces between the air gap and, respectively, the pattern device and the projection lens device. Further, the construction of the lighting system becomes less complex because the projection lens device itself controls the predefined distance between the pattern device and the projection lens device and no other means have to be introduced to control such spacing.

Optionally, the light sources comprise a solid state light emitter. Solid state light emitters are relatively compact, and, thus, result in a relatively small lighting system. Further, solid state light emitters are relatively efficient, and, consequently, result in a relatively efficient lighting system. Examples of solid state light emitters are Light Emitting Diodes (LEDs), Organic Light Emitting diode(s) (OLEDs), or, for example, laser diodes.

Optionally, the light sources may comprise further optical for obtaining the light beam. If light beams emitted by light emitters of the light sources have not the shape to be emitted by the light sources, reflectors, or light source lenses may be provided to shape the light beam emitted by the light emitter into the light beam to be emitted by the light source.

According to a second aspect of the invention, a luminaire is provided which comprises the lighting system according to the first aspect of the invention. Such a luminaire is, for example, an outdoor lighting luminaire such as a street-lamp.

The luminaire according to the second aspect of the invention provides the same benefits as the lighting system according to the first aspect of the invention and has similar embodiments with similar effects as the corresponding embodiments of the system.

Optionally, the luminaire is configured for outdoor lighting. The skilled person knows which features need to be added to a luminaire such that is may be used in an outdoor lighting system. It should, for example, be weather proof.

Optionally, the luminaire comprises a mast and a light head and the lighting system is provided in the light head. The light head is arranged to light an area below the light head and project an image of the at least partially light- shaping patterns downward in the area.

Optionally, the distances between the at least partially light-shaping patterns are chosen to create various luminances of the light head of the luminaire when a viewer is looking directly to the light head. These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.

It will be appreciated by those skilled in the art that two or more of the above- mentioned options, implementations, and/or aspects of the invention may be combined in any way deemed useful.

Modifications and variations of the system, which correspond to the described modifications and variations of the system, can be carried out by a person skilled in the art on the basis of the present description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

Fig. 1 schematically shows a cross-section of a first embodiment of a

lighting system according to the first aspect of the invention,

Fig. 2 schematically shows a cross-section of a second embodiment of the lighting system,

Fig. 3 schematically shows an exploded view of a third embodiment of the lighting system,

Fig. 4 schematically shows a cross-section of fourth embodiment of the lighting system,

Fig. 5 schematically shows a luminaire comprising a lighting system

according to the first aspect of the invention, and

Fig. 6 schematically shows an exploded view of a basic embodiment of the lighting system.

It should be noted that items denoted by the same reference numerals in different Figures have the same structural features and the same functions, or are the same signals. Where the function and/or structure of such an item have been explained, there is no necessity for repeated explanation thereof in the detailed description.

The Figures are purely diagrammatic and not drawn to scale. Particularly for clarity, some dimensions are exaggerated strongly.

DETAILED DESCRIPTION

Fig. 1 schematically shows a cross-section of a first embodiment of a lighting system 100 according to the first aspect of the invention. The lighting system 106 comprises a light source assembly 1 10 which comprises a plurality of light source 116. Each light source 116 comprises a light emitter 112 and an optional reflector 114. The light sources 116 emit a light beam 118. Optionally, each light beam 118 has substantially the same direction and the same shape - however, some tolerances are accepted: directions of different light source 116 may slightly vary and shapes of the different light beams 118 may also slightly vary.

The lighting system 100 also comprises a pattern device 104. The light beams 118 are emitted by the light sources 116 towards the pattern device 104. The pattern device 104 is made of a transparent material, such as, for example, glass or a transparent synthetic material such as poly methyl methacrylate (PMMA) or poly carbonate. The pattern device 104 may be a flexible sheet of the transparent material or a solid layer of the transparent material. The pattern device 104 comprises a plurality of patterns being at least a partially light blocking pattern arranged on a surface of the pattern device 104 or being arranged in the material of the pattern device 104.

The lighting system 100 further comprises a projection lens device 106. The projection lens device 106 is arranged to receive light from the light source assembly 110 via the pattern device 104. The projection lens device 106 is configured to refract the light beams emitted by the light source 116 to an area 122, which is to be lightened, and the projection lens device 106 is configured to project the patterns of the pattern device in the area 122 to be lightened. The projection lens device 106 comprises a plurality of projection lenses.

The plurality of light sources 106 are arranged in an imaginary plane at a predefined pitch p. The light sources 116 may be arranged in columns and rows such that the distance between the columns and rows is the distance p. The light sources 116 may also be arranged in a honeycomb-like-structure, wherein light sources which are not arranged at the edge of the structure have 6 neighboring light sources 116 and a distance between the centers of neighboring light sources 116 is equal to the pitch p.

The at least partially light blocking patterns 102 of the pattern device 104 are also arranged at the same pitch p as the light sources 116. This means that, if the light sources 116 are arranged in a matrix with the distance p between the rows and columns, that the patterns 102 are also arranged in such a matrix. If the light sources 116 are arranged in a honeycomb-like-structure, than the patterns 102 are also arranged in such a structure. The plane of the pattern device 104 is arranged parallel to the imaginary plane in which the light sources 116 are arranged. Optionally, the number of patterns 102 is at least the number of light source 116. The at least partially light blocking patterns 102 are drawn schematically by means of the dotted rectangles in Fig. 1. In practice the pattern device 104 comprises partially light blocking ink or structures on a surface of the pattern device 104 or comprises partially light blocking structures within the transparent material of the pattern device 104. In an embodiment, the at least partially light blocking patterns 102 are equal to each other and arranged in the same orientation on the pattern device 104 to obtain a well superposition of the projection of each one of the at least partially light blocking patterns 102. At least partially light blocking means that the pattern may locally transmit a portion of the light, meaning that along the whole spectrum emitted by the light sources 116 a portion of the light is blocked, or that some specific wavelengths are blocked in order to obtain a projected pattern of a specific color.

The projection lens device 106 comprises a plurality of projection lenses 108. Optionally, the number of projection lenses 108 is at least equal to the number of light sources 116. The projection lenses 108 are arranged in an imaginary plane which is parallel to the pattern device 104 and are arranged at the same pitch p as the light sources 116 are arranged. Thus, if the light sources 116 are arranged in a matrix arrangement, the projection lenses 108 are also arranged in a matrix. If the light sources 116 are arranged in a

honeycomb-like-structure, the projection lenses 108 are also arranged in such a structure. It is to be noted that the at least partially light blocking patterns 102 are arranged in the focal planes of the projection lenses 108. Thus, as indicated in Fig. 1, the distance between the center of the projection lenses 108 and the at least partially light blocking patterns 102 is the distance /being the focal distance of the projection lenses.

The projections lenses 108 of the projection lens device 106 are made of a transparent material which advantageously refracts light. For example, glass can be used. In another embodiment, the material poly methyl metacrylate (PMMA) is used for the projection lenses 108 resulting in the advantage that the presence of chromatism in the projected pattern 120 is limited.

The projection lens device 106 refracts the light of the light sources such that the area 122 is illuminated. In Fig. 1 the projected pattern 120 is schematically indicated with the thin black rectangles which indicate that locally less light is projected by the lighting system 100. The projected pattern 120 is a superposition of different projected patterns which originate from the different at least partially light blocking patterns 102 of the pattern device 104. The distance between the lighting system 100 and the lightened area is indicated in Fig. 1 by the distance d. The ratio between the pitch p and the distance d is such that the different projected patterns are well superposed to prevent blurring of the projected pattern 120. In general this means that the Gauss conditions have to be fulfilled. However, a designer of the lighting system 100 of Fig. 1 has a choice to make the lighting system 100 less complex and/or less expensive at the cost of some blurriness of the projected pattern 120. In specific applications, a relatively small amount of blur can be accepted, such as, for example, lighting an uneven outdoor surface. In an embodiment the ratio between p and d is smaller than or equal to 0.01.

Fig. 2 schematically shows a cross-section of a second embodiment of the lighting system 200. The lighting system 200 is similar to the lighting system 100, however, some aspects are different: The lighting system 200 comprises a housing 202 which has a light exit window at which the projection lens device 106 is provided. The projection lens device 106 has the same function and same possible structures as discussed previously in the context of Fig. 1. The housing 202 further has a closable opening 204 which can be used to pull or push 206 the pattern device 104 out or in the housing 202. The pattern device 104 has the same function and same possible structures as discussed in the context of Fig. 1. The closable opening 204 allows interchanging the pattern device 104 with another pattern device to project another pattern to the lightened area 122. Further, inside the housing 202 a plurality of light sources 212 are arranged opposite the light exit window of the housing 202. Each light source 212 comprises a reflector 114 for creating a light beam 118 towards the pattern device 104. Other optical elements to shape the light beams 118 may be used as well.

Further, each light source 212 comprises a Light Emitting Diode (LED) 210 which emits light. The LEDs are a specific type of a solid state light emitter. Other solid state light emitters may be used as well, such as laser diodes or Organic LEDs. Furthermore, the embodiments of the light emitter are not limited to solid state light emitters. Traditional incandescent lamps, or light tubes may be used as well. Moreover, the LEDs may also comprise luminescent material to convert light emitted by the LEDs towards light of another color.

In Fig. 2 imaginary optical axes 208 are drawn. The imaginary optical axes 208 are the optical axes of the projection lenses 108 and a single optical axis 208 is also a central axis of the light beam 118 emitted by the nearest light source 212 and is going through a reference point of the nearest at least partially light blocking pattern 102. Thus, each light source 212 forms together with its nearest at least partially light blocking pattern 102 and its nearest projection lens 108 a 3-turple and an imaginary optical axis 208 optically aligns the three elements of the 3 -tuple such that the at least light blocking pattern 102 of the 3-turple is well projected on the lightened area 122. The imaginary optical axes 208 are arranged parallel to each other such that all projected patterns are well superposed. The 3-tuple is a group of three entities (E_{l s} E₂, E₃), wherein Ei is an instance of a light source, E₂ is an instance of a pattern being nearest to the light source E_{l s} and E₃ is an instance of a projection lens being nearest to the light source Ei.

Fig. 3 schematically shows an exploded view of a third embodiment of the lighting system 300. The basis of the lighting system is a box 310 in which three light sources 308 are provided. The light sources 308 are arranged in a triangular spatial arrangement and the distance between two neighboring light sources 308 is the pitch distance p. The light sources 308 are, for example, LEDs. The pitch distance p is, for example, in the range of 10 to 50 millimeter. In a specific embodiment, the pitch distance is 16 millimeter.

At a distance dl from the light sources a pattern device 304 is provided. The distance dl is, for example, 10 millimeter. The pattern device is, for example, a transparent sheet on which three light blocking patterns 302 are arranged in a similar triangular spatial arrangement. The distance between each pair of two neighboring light blocking patterns 302 is also the pitch distance p. The light blocking patterns 302 are, seen in the drawn projection of Fig. 3, on top of the light sources 308. The light blocking pattern 302 comprises a plurality of black lines which are printed on the transparent sheet. The lines are, for example, at least 0.05 millimeter wide.

The lighting system 300 further comprises a projection lens device 306 which is arranged parallel to the pattern device 304 and a distance between the projection lens device 306 and the pattern device 304 is the focal distance / of the plurality of projection lenses 108 of the projection lens device 306. The projection lenses 108 are also arranged in a similar triangular spatial arrangement and pairs of neighboring projection lenses 308 have the pitch distance p between the centers of the projection lenses 308. The projection lenses are, seen in the drawn projection of Fig. 3, placed exactly above the light sources 308 and the light blocking patterns 302. The focal distance /is, for example, a value in the range from 5 to 30 millimeter. Furthermore, the projection lenses 108 are as large as possible to catch as much as possible light to refract a significant amount of light to the area 322 to be lightened. The diameter of the projection lenses 108 are, for example, between 10 and 40 millimeter. The projection lens 108 thickness should remain within the limits of manufacturability of the projection lenses 108, for example, when the projection lens device 306 is made of a transparent synthetic material and is manufactured by injection molding, the projection lens 108 should still be injectable. The positioning of the projection lenses 108 with respect to the light sources 308 is such that, given a certain focal distance of the projection lenses 108 and given a certain light beam emitted by the light source 308, that a full lighting of the area 322 to be lightened is obtained.

The lighting system 300 lightens an area 322 at a relatively large distance d2 away from the lighting system. The distance d2 may, for example, be 5 meters and the lightened area has, for example, a size of 10 by 10 meters. On the area 322 is projected the pattern 320 which is a superposition of the three patterns 302 of the pattern device 304. The light blocking patterns 302 of the pattern device 304 are enlarged by the projection lenses 108 and projected sharply on the area 322.

In Fig. 3 the light sources 308, the light blocking patterns 302 and the projection lenses 108 are all arranged in a similar spatial arrangement. It is to be noted that they may be arranged in other spatial arrangement as long as the spatial arrangement of the light blocking patterns 302 is similar to the spatial arrangement of the projection lenses. It is optional to have a similar spatial arrangement between the light sources 308 and the light blocking patterns 302.

Fig. 4 schematically shows a cross-section of fourth embodiment of the lighting system 400. The lighting system 400 is similar to previously discussed embodiments. The lighting system 400 comprises a base 412 of a solid material. On top of the base 412 is provided a housing 414 for the light sources 418. The housing 414 is made of a light reflective material and comprises recesses 416 in which light sources 418 are provided. The light sources 418 are, for example, Light Emitting Diodes (LEDs). The light sources 418 emit light toward the light exit window of the recesses 416 into the direction of a pattern device 408. The light reflective material of the housing 414 reflects light which impinges on the walls to prevent the absorption of light. The pattern device 408 is provided on top of the light source 418 housing 414. The pattern device 408 comprises partially light blocking patterns 404 at the light exit windows of the recesses 416. On top of the pattern device 408 is provided a projection lens device 406 which comprises a layer of a transparent material which has at one side a plurality of projection lenses 402. The projection lenses 402 are aligned with its nearest light source 418 and nearest partially light blocking pattern 404. The projection lens device 406 is fastened with crews 410 into the base 412. The pattern device 408 is clamped between the projection lens device 406 and the housing 414. Thus, the pattern device 408 may be interchanged with other pattern devices to allow the projection of different patterns. It is to be noted that Fig. 4 presents a cross-section of the lighting system 400. The lighting system 400 may have a disk shape or a box shape. Furthermore, the light sources 418, the partially light blocking patterns 404 and the projection lenses 402 may be arranged in a matrix or in a honeycomb-like-structure.

Fig. 5 schematically shows an outdoor luminaire 502 comprising a lighting system 504 according to the first aspect of the invention. The outdoor luminaire 502 is, for example, a street-lamp. The luminaire 502 is arranged near a public footpath 506 and lightens the area 508 of the footpath. The luminaire comprises a lighting system 504 according to the first aspect of the invention, and the plurality of light diffusive patterns on the pattern device of the lighting system 504 are a symbolic drawing of an atom. As such, the projected pattern 510 is a superposition of the plurality of light beams as shaped or modified by light diffusive patterns. A projection of a pattern 510 on the public footpath 506 makes the lightened area more attractive for people walking on the footpath.

Fig. 6 schematically shows a basic embodiment of the lighting system according to the invention. The lighting system is the same as shown in Fig. 3 and same reference numbers are used to indicate the same features, but in which the projection lens device is absent in the lighting device, and that d2 is now representing the distance between the pattern device 304 and the illuminated area 322. The superpositioning of the patterns 302 that form the image pattern 320 therefore is less optimal than is the case for the lighting system of Fig. 3. Contrary to what is the case in the lighting system of Fig. 3, in which the pitch p between the patterns 302 is corrected by the projection lens device, this correction does not occur in the lighting system of Fig. 6 but said pitch p is readily transferred to the illuminated area, resulting in a somewhat less sharper image pattern 320 (said effect is not shown in Fig.6). The lighting system as shown in Fig. 6 enables a much more convenient exchange of pattern device 104 compared to the exchange of the pattern device in the lighting device comprising the projection lens device as alignment of the patterns 302 with (only) the light sources 308 is both simpler and less critical than the alignment of the image pattern 302 with both the light sources 308 and the lenses 108.

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 from the scope of the appended claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. 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.

Claims

CLAIMS:

1. A lighting system (100, 200, 300, 400, 504) comprising:

a light source assembly (110, 310, 414) comprising a plurality of light sources (116, 212, 308, 418) according to a determined spatial arrangement, each light source (116, 212, 308, 418) providing a light beam (118),

a pattern device (104, 304, 408) of a material being at least partially transparent, the pattern device (104, 304, 408) comprising a plurality of light-shaping patterns (104, 302, 404) according to the determined spatial arrangement,

during operation of the lighting system, the light source is to issue the light beams (118) via the pattern device to lighten an area (122, 508) for projecting an image pattern (120) of the light-shaping patterns (104, 302, 404) in the area (122, 508).

2. A lighting system (100, 200, 300, 400, 504) according to claim 1, wherein it further comprises a projection lens device (106, 306, 406) arranged to receive light from the light source assembly (110, 310, 414) via the pattern device (104, 304, 408) for refracting the light beams (118) to lighten the area (122, 508) and for projecting the image pattern of the light-shaping patterns (104, 302, 404) in the area (122, 508), the projection lens device (106, 306, 406) comprising a plurality of projection lenses (108, 402) arranged according to the spatial arrangement, wherein the focal planes of the plurality of projection lenses (108, 402) at least partially coincide with the pattern device (104, 304, 408).

3. A lighting system (100, 200, 300, 400, 504) according to claim 1, wherein the light-shaping patterns (104, 304, 408) extend over a pattern surface, wherein the light sources (116, 212, 308, 418) are arranged over a light surface parallel to the pattern surface.

4. A lighting system (100, 200, 300, 400, 504) according to claim 2, wherein the light-shaping patterns (104, 304, 408) extend over a pattern surface, wherein the light sources (116, 212, 308, 418) are arranged over a light surface parallel to the pattern surface and/or the projection lenses are arranged over a lens surface parallel to the pattern surface.

5. A lighting system (100, 200, 300, 400, 504) according to claim 1 or 3, wherein the light-shaping patterns (104, 304, 408) are arranged according to regular pitches (p).

6. A lighting system (100, 200, 300, 400, 504) according to claim 2 or 4, wherein the light-shaping patterns (104, 304, 408) are arranged according to regular pitches (p) and wherein the projection lenses are arranged according to similar regular pitches (p).

7. A lighting system (100, 200, 300, 400, 504) according to claim 5 or 6, wherein the light sources (116, 212, 308, 418) are arranged according to similar regular pitches.

8. A lighting system (100, 200, 300, 400, 504) according to claim 1 or 2, wherein the light beams (118) emitted by the plurality of light sources (116, 212, 308, 418) have all substantially the same shape and/or have all substantially the same direction.

9. A lighting system (100, 200, 300, 400, 504) according to claim 1, wherein each light source (116, 212, 308, 418) forms a sub-lighting system together with a nearest light-shaping pattern (104, 302, 404) on the pattern device (104, 304, 408), a sub-optical axis (208) of a sub-lighting system being defined from a line passing through respectively a center of the light source and a reference point of the light-shaping pattern (104, 302, 404).

10. A lighting system (100, 200, 300, 400, 504) according to claim 2, wherein each light source (116, 212, 308, 418) forms a sub-lighting system together with a nearest light-shaping pattern (104, 302, 404) on the pattern device (104, 304, 408) and a nearest projection lens (108, 402) of the projection lens device (106, 306, 406), a sub-optical axis (208) of a sub-lighting system being defined from a line passing through respectively a center of the light source, a reference point of the light-shaping pattern (104, 302, 404) and a center of the projection lens (108, 402), wherein the light source assembly (116, 212, 308, 418), the pattern device (104, 304, 408) and the projection lens device (106, 306, 406) are arranged such that at least a part of the sub-optical axes (208) are parallel to each other.

11. A lighting system (100, 200, 300, 400, 504) according to claim 1 or 2, wherein the light shaping patterns (104, 302, 404) are filters or pictures similar to each other.

12. A lighting system (100, 200, 300, 400, 504) according to claim 1 or 2, wherein the pattern device (104, 304, 408) is a layer of the material and the pattern device (104, 304, 408) is arranged interchangeable in the lighting system (100, 200, 300, 400, 504) for allowing the replacement of the pattern device (104, 304, 408).

13. A lighting system (100, 200, 300, 400, 504) according to claim 2, wherein the projection lens device (106, 306, 406) comprises a molded flat base and the projection lenses protruding from a face of the flat base, the projection lenses (108, 402) being made integral with or fixed to the flat base, the flat base is arranged in contact with the pattern device (104, 304, 408) and is sufficiently thick to obtain a predefined distance between the pattern device (104, 304, 408) and the projection lenses (108, 402).

14. A lighting system (100, 200, 300, 400, 504) according to claim 1 or 2, wherein the light sources (116, 212, 308, 418) comprise further optics (114) for obtaining the light beam (118).

15. A luminaire (502) comprising the lighting system (100, 200, 300, 400, 504) according to claim 1 or 2.