Lighting apparatus

The invention relates to a lighting apparatus comprising a laser source (2) for emitting laser light (3). The lighting apparatus further comprises a first laser light modification unit (7) for modifying an optical characteristic of the laser light, which first laser light modification unit (7) is situated at a first location, and a second laser light modification unit (8) for modifying an optical characteristic of the laser light, which second laser light modification unit (8) is situated at a second location. The lighting apparatus further comprises a laser light distribution modification unit (4) for modifying a laser light distribution (5, 6) directed onto at least one of the first and second laser light modification units (7, 8) from a first to a second laser light distribution which is different from the first laser light distribution.

FIELD OF THE INVENTION

The invention relates to a lighting apparatus, a lighting method and a computer program for controlling the lighting apparatus.

BACKGROUND OF THE INVENTION

WO 2006/007301 A1 discloses a lighting apparatus including a light source, a light guide comprising an output surface, emissive material positioned between the light source and the output surface of the light guide, and an interference reflector positioned between the emissive material and the output of the light guide. The light source emits light having a first optical characteristic. The emissive material emits light having a second optical characteristic when illuminated with light having the first optical characteristic. The interference reflector substantially transmits light having the second optical characteristic and substantially reflects light having the first optical characteristic. This lighting apparatus has the drawback that the illumination configuration is fixed and cannot be modified easily.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a lighting apparatus, a lighting method and a computer program for controlling the lighting apparatus, wherein the illumination configuration can be modified more easily.

In a first aspect of the present invention, a lighting apparatus is provided, comprising:a laser source for emitting laser light,a first laser light modification unit for modifying an optical characteristic of the laser light, the first laser light modification unit being situated at a first location,a second laser light modification unit for modifying an optical characteristic of the laser light, the second laser light modification unit being situated at a second location,a laser light distribution modification unit for modifying a laser light distribution directed onto at least one of the first and second laser light modification units from a first laser light distribution to a second laser light distribution which is different from the first laser light distribution.

The invention is based on the recognition that the illumination configuration can be modified easily if laser light of a laser source is directed onto at least one of a first and a second laser light modification unit which are situated at a first and a second location, respectively, and if a laser light distribution modification unit modifies the laser light distribution directed onto at least one of the first and second laser light modification units from a first to a second laser light distribution which is different from the first laser light distribution. For example, the first laser light distribution may correspond to laser light directed onto the first laser light modification unit only, and the second laser light distribution may correspond to laser light directed onto the second laser light modification unit only. Since the first and the second laser light modification unit are situated at a first and a second location, respectively, the illumination configuration is modified by modifying the laser light distribution from the first to the second laser light distribution. Furthermore, since a laser source provides laser light with a laser beam having a high energy density nature, the light energy can be transported to at least one of the first and second laser light modification units over relatively large distances, while the light energy is confined to a very small beam diameter. A small shift in the position of the laser beam, for example, a small shift of a fraction of a millimeter, can be sufficient to modify the laser light distribution directed onto at least one of the first and second laser light modification units. The combination of a laser source, a first laser light modification unit situated at a first location, a second laser light modification unit situated at a second location and a laser light distribution modification unit for modifying the laser light distribution directed onto at least one of the first and second laser light modification units from a first to a second laser light distribution thus allows easy modification of the illumination configuration.

The first and the second location are preferably different. Furthermore, the lighting apparatus may comprise several first and/or several second laser light modification units, and the laser light distribution can be modified to several first and/or several second laser light distributions, i.e. the invention is not limited to only two laser light modification units or to only two laser light distributions.

The first and second laser light modification units are adapted to modify an optical characteristic of the laser light which is directed onto these units. The optical characteristic, which can be modified by the first and/or second laser light modification units is, for example, the spectral distribution of the light, its collimation, direction, intensity and/or beam pattern. The spectral distribution and other properties of the light directed onto at least one of the first and second laser light modification units can be modified, for example, by luminescent material which emits luminescent light if the laser light is directed onto this luminescent material. The spectral and also other characteristics of the laser light can thus be modified by total or partial conversion using luminescent materials such as organic or inorganic phosphors. In one embodiment, a beam pattern, which can be generated by at least one of the first and second laser light modification units is, for example, a picture or a word.

The laser light distribution unit preferably comprises optical elements which allow modification of a laser light distribution directed onto at least one of the first and second laser light modification units from a first to a second light distribution which is different from the first laser light distribution. These optical elements are, for example, beam splitters, mirrors, polarization rotators, etc.

The first and second laser light modification units can be arranged adjacent to each other, such that for a person seeing the light emanating from the first and second laser light modification units, the light seems to be emitted from the same location. In another embodiment, one of the first and second laser light modification units or several first and second light modification units forming a first group can be situated at a first location, and the other of the first and second laser light modification units or another group of first and second laser light modification units can be situated at a second location, wherein the first and the second location are not adjacent to each other so that a person can distinguish between light coming from the first location and light coming from the second location. For example, in one embodiment, the first location is situated in the ceiling of a room above a table for illuminating substantially only this table, and the second location is situated in the ceiling in the middle of the room for illuminating a larger part of this room. The distance between the first and the second location is preferably larger than one centimeter, more preferably larger than ten centimeters and even more preferably larger than one meter. The distance between adjacent laser light modification units is preferably smaller than 1 centimeter, preferably smaller than 0.5 centimeter and preferably smaller than 1 millimeter.

If, in one embodiment, the lighting apparatus is located in a ceiling of a room, the room preferably comprises an intermediate ceiling forming a space between this intermediate ceiling and a further ceiling located above the intermediate ceiling. The intermediate ceiling preferably comprises tiles which can be opened, and the further ceiling is preferably a concrete ceiling. The lighting apparatus is preferably arranged within the space defined by the intermediate ceiling and the further ceiling so that persons who might be in the room cannot come into contact with the laser light. In particular, the lighting apparatus may comprise a security mechanism which is adapted in such a way that the laser source is switched off if a tile of the intermediate ceiling is opened.

The laser light distribution directed onto at least one of the first and second laser light modification units preferably defines how each of these units is illuminated by the laser light, for example, the laser light can be directed onto a first laser light modification unit only, onto a second laser light modification unit only, or onto a first and a second laser light modification unit.

The first and the second laser light distribution are preferably static laser light distributions, i. e. the laser light distribution is not continuously non-stop modified, for example, a light beam does not continuously scan several pixels as in a display, but the laser light distribution remains in the first or in the second laser light distribution for a predefined time, which is preferably longer than 0.5 seconds, preferably longer than 1 second, preferably longer than 30 seconds and preferably longer than 1 minute.

It is preferred that the first and second laser light modification units are adapted to modify the optical characteristic of the laser light differently. This allows modification of the optical characteristic of the light from at least one of the first and second laser light modification units by modifying the laser light distribution from a first to a second laser light distribution. Further modifications of the illumination configuration can thus be easily achieved.

It is further preferred that at least one of the first and second laser light modification units comprises a luminescent material for emitting luminescent light if the laser light is directed onto the luminescent material. The luminescent light has one or several wavelengths which are different from one or several wavelengths of the laser light. The spectral distribution of the laser light and the luminescent light may correspond to a single wavelength or to several wavelengths.

It is preferred that the first laser light modification unit comprises a first luminescent material for emitting first luminescent light if the laser light is directed onto the first luminescent material, while the second laser light modification unit comprises a second luminescent material for emitting second luminescent light if the laser light is directed onto the second luminescent material, and the spectral distributions of the first and the second luminescent light are different. In particular, the first and the second luminescent light have different colors or different color temperatures. In a preferred embodiment, the lighting apparatus may comprise at least one color unit for generating light having a modifiable color, wherein the color unit comprises at least two luminescent materials of the first and the second luminescent material, and the laser light distribution modification unit is adapted to adjust the ratio of the intensity of the laser light directed onto one of the at least two luminescent materials to the intensity of the laser light directed onto the other of the at least two luminescent materials, while different ratios of intensity of the laser light correspond to different first and second laser light distributions, and the spectral distribution of the luminescent light emitted by one of the at least two luminescent materials is different from that of the luminescent light emitted by the other of the at least two luminescent materials. This allows modification of the color of the light emitted by the color unit by modifying the laser light distribution from a first to a second laser light distribution, particularly by modifying the ratio between the intensity of the laser light directed onto at least one of the first and second luminescent materials and the intensity of the laser light directed onto the other of the first and second luminescent materials. In one embodiment, the ratio between the intensity of the laser light directed onto at least one of the first and second luminescent materials and the intensity of the laser light directed onto the other of the first and second luminescent materials is determined by moving a laser spot formed by the laser light from one to the other luminescent material. During this process, the spot can be located on one of these luminescent materials only or on both. By moving the laser spot, the areas illuminated by the laser light on the first and on the second luminescent material can be modified in order to control the color and/or the color temperature of the light emitted by the color unit.

The laser light distribution modification unit preferably does not comprise absorbing elements. The overall intensity of the laser light generated by the laser source is preferably modified by modifying the power of the laser source only.

It is further preferred that the first laser light distribution comprises an intensity distribution of the laser light directed onto at least one of the first and second laser light modification units, which is different from the intensity distribution of the laser light directed onto at least one of the first and second laser light modification units of the second laser light distribution. Since the intensity distribution can be modified easily, for example, by using polarization direction rotators, half-wave plates in combination with polarizing beam splitters, rotatable reflectors and dielectrics, switchable reflectors with controllable transmission and reflection beam manipulators based on the electro-wetting principle and electrophoretic cells, the laser light distribution can easily be modified from a first to a second laser light distribution by modifying the intensity distribution of the laser light. In a preferred embodiment, the laser light distribution modification unit is adapted to modify only the intensity distribution of the laser light directed onto at least one of the first and second laser light modification units. In another embodiment, the laser light distribution is modified by moving a laser spot directed onto at least two laser light modification units from one to the other laser light modification unit so that the laser spot is located on one of these laser light modification units only or on both, as described above with reference to the color unit.

It is further preferred that the laser light distribution modification unit comprises at least one beam-splitting unit for splitting the laser light into a first beam directed onto the first laser light modification unit and a second beam directed onto the second laser light modification unit, wherein the at least one beam-splitting unit is adapted in such a way that an intensity of at least one of the first and second beams is modifiable. The first and/or the second beam can be directly directed onto the first and/or the second laser light modification unit, respectively, or via at least one optical element such as a redirection element or redirection unit, for example, a mirror. For modifying the intensity of at least one of the first and second beams, the beam-splitting unit preferably comprises an intensity modification element, which is, for example, a polarization converter or polarization rotator. For example, a half-wave plate can be rotated with respect to the direction of polarization of a beam of polarized laser light changing the state of polarization of the laser light and eventually changing the direction of polarization. In this way, laser light incident on a polarizing beam splitter can be sent totally in one or in another of the beam-splitting directions. In an intermediate state, in which light is, for example, elliptically polarized, the ratio between the intensities of the laser light in one of the beam-splitting directions and the laser light in another of the beam-splitting directions can be adjusted. Instead of a half-wave plate, also other elements for modifying the polarization of the laser light can be used, for example, a liquid-crystal cell in an electrical birefringence mode for adjusting the direction and the state of polarization of the laser light. Also a liquid-crystal cell in the twisted-nematic configuration can be used for modifying the polarization. If an intensity-modifying element is used, this element is preferably located in the first and/or in the second beam. By using this beam-splitting unit, the laser light distribution can be easily modified from a first to a second laser light distribution, and the illumination configuration can thus be easily modified.

It is further preferred that the laser light distribution modification unit comprises several beam-splitting units for splitting the laser light into a first and a second beam, wherein at least one of the first and second laser light modification units is assigned to at least one of the beam-splitting units, the beam-splitting units being adapted to direct the first beam of at least one of the beam-splitting units to the at least one of the first and second laser light modification units assigned to the at least one beam-splitting unit and to direct the second beam of the at least one beam-splitting unit to another beam-splitting unit, the at least one beam-splitting unit being adapted in such a way that an intensity of at least one of the first and the second beam is modifiable. This allows several of the beam-splitting units to be arranged along a line, wherein the laser light is directed from a first to a second beam-splitting unit, and so forth. Since the intensity of at least one of the first and second beams of at least one beam-splitting unit is modifiable, the laser light distribution directed onto the laser light modification units assigned to the beam-splitting units can be easily modified, thereby modifying the illumination configuration. Each beam-splitting unit is preferably adapted to modify the intensity of at least one of the first and second beams, which allows modification of the laser light distribution between many different first and second laser light distributions. Particularly if the intensity can be modified continuously, the laser light distribution can be modified between a continuum of different laser light distributions which can be regarded as first and second laser light distributions, which are preferably static, i.e. if a desired laser light distribution, i.e. a desired first or second laser light distribution has been reached, the laser light distribution remains unchanged during the above-mentioned predefined time.

It is further preferred that at least one of the first and second laser light modification units comprises a beam-shaping unit for beam-shaping light directed onto the beam-shaping unit. This allows modification of the beam shape by modifying the laser light distribution directed onto at least one of the first and second laser light modification units. Consequently, the beam shape and thus the illumination configuration can be easily modified by modifying the laser light distribution directed onto at least one of the first and second laser light modification units.

It is further preferred that the first laser light modification unit comprises a first beam-shaping unit for beam-shaping light directed onto the first beam-shaping unit, and the second laser light modification unit comprises a second beam-shaping unit for beam-shaping light directed onto the second beam-shaping unit, the first and the second beam-shaping unit being adapted to beam-shape light differently. This allows modification of the shape of the light beam from the first and/or the second laser light modification unit and hence the illumination configuration by modifying the laser light distribution directed onto at least one of the first and second laser light modification units.

It is further preferred that at least one of the first and second laser light modification units comprises a redirection unit for redirecting light directed onto the at least one of the first and second laser light modification units. This allows easy modification of the direction of the light from at least one of the laser light modification units and hence the illumination configuration by modifying the laser light distribution directed onto at least one of the first and second laser light modification units.

In a preferred embodiment, the first laser light modification unit comprises a first redirection unit for redirecting light directed onto the first laser light modification unit, and the second laser light modification unit comprises a second redirection unit for redirecting light directed onto the second laser light modification unit, the first and the second redirection unit being adapted to redirect light in different directions. This allows modification of the direction of the light beam from at least one of the first and second laser light modification units and hence modification of the illumination configuration by modifying the laser light distribution directed onto at least one of the first and second laser light modification units.

The laser light distribution modification unit is preferably adapted in such a way that it can adjust the ratio between the intensity of laser light directed onto the first laser light modification unit and the intensity of laser light directed onto the second laser light modification unit in such a way that a first laser light modification unit is illuminated in a first laser light distribution only, a second laser light modification unit is illuminated in a second laser light distribution only, and that two or more first and second laser light modification units are illuminated simultaneously in a further laser light distribution, wherein the ratio between the intensity of the laser light directed onto a first laser light modification unit and the intensity of the laser light directed onto a second laser light modification unit can be modified. Different ratios preferably correspond to different laser light intensity distributions.

It is further preferred that the lighting apparatus comprises a laser light modification unit sensor for determining the position of at least one of the first and second laser light modification units, and a control unit for controlling the laser light distribution modification unit in such a way that laser light of the first and second laser light distributions meets at least one of the first and second laser light modification units, using the determined position. This allows, for example, manual modification of the position of at least one of the laser light modification units, in which position the lighting apparatus is still operable.

In a preferred embodiment, the lighting apparatus further comprises a person presence sensor for determining whether a person is present in the vicinity of the lighting apparatus, and a control unit for controlling the lighting apparatus in dependence on the determination whether a person is present in the vicinity of the lighting apparatus. It is further preferred that the person presence sensor is adapted to determine whether or not a person is moving in the vicinity of the lighting apparatus, in which case the control unit is adapted to control the lighting apparatus in dependence on the determination whether a person is moving in the vicinity of the lighting apparatus. The lighting apparatus is located in, for example, a room in which the vicinity of the lighting apparatus is, for example, an area within the room close to this lighting apparatus, or the whole room is regarded as being the vicinity of the lighting apparatus. This allows adaptation of the illumination configuration to the movement or presence of a person in the vicinity of the lighting apparatus, particularly in a room in which the lighting apparatus is located.

In a further aspect of the present invention, a lighting method is provided, comprising the steps of:emitting laser light from a laser source,directing the laser light onto at least one of a first and a second laser light modification unit, the first laser light modification unit being situated at a first location and adapted to modify an optical characteristic of the laser light, the second laser light modification unit being situated at a second location and adapted to modify an optical characteristic of the laser light,modifying, by means of a laser light distribution modification unit, a laser light distribution directed onto at least one of the first and second laser light modification units from a first to a second laser light distribution which is different from the first laser light distribution.

In a further aspect of the present invention, a computer lighting program is provided, comprising program code means for causing a lighting apparatus as defined in claim1to carry out the steps of the lighting method as defined in claim14, when the computer program is run on a computer controlling the lighting apparatus.

It is to be noted that the lighting apparatus of claim1, the lighting method of claim14and the lighting computer program of claim15have similar and/or identical preferred embodiments as defined in the dependent claims.

It is also to be noted that a preferred embodiment of the invention may be alternatively any combination of the dependent claims with the respective independent claim.

DESCRIPTION OF EMBODIMENTS

FIG. 1shows schematically, by way of example, an embodiment of a lighting apparatus1comprising a laser source2for emitting laser light3. The lighting apparatus1further comprises a first laser light modification unit7situated at a first location and adapted to modify an optical characteristic of the laser light in such a way that modified light is generated. For example, if the first laser light modification unit7comprises a first luminescent material, first luminescent light9is emitted if the laser light3,5is directed onto the first luminescent material, wherein the spectral distribution of the first luminescent light9is different from the spectral distribution of the laser light3,5.

The lighting apparatus1further comprises a second laser light modification unit8situated at a second location and adapted to modify an optical characteristic of the laser light in such a way that modified light10is generated. For example, if the second laser light modification unit8comprises a second luminescent material, second luminescent light10is emitted if the laser light3,6is directed onto the second luminescent material8, wherein the spectral distribution of the second luminescent light10is different from the spectral distribution of the laser light3,6.

The lighting apparatus1further comprises a laser light distribution modification unit4for modifying the laser light distribution, which is indicated inFIG. 1by two arrows5,6, directed onto at least one of the first and second laser light modification units7,8from a first to a second laser light distribution which is different from the first laser light distribution. In this embodiment, the first and second laser light distributions are static laser light distributions.

The spectral distributions of the first modified light9and the second modified light10are preferably different. This allows modification of the color of the light9,10transformed by the first and second laser light modification units7,8, and, in particular, emitted by the first and second luminescent materials, by modifying the ratio of the intensity of the laser light5,6directed onto the first and second laser light modification units7,8. The combination of the laser light distribution modification unit4and the first and second laser light modification units7,8comprising, in particular, the first and second luminescent materials can thus be regarded as a color unit for generating light having a modifiable color.

FIG. 2shows schematically, by way of example, another embodiment of a lighting apparatus801according to the invention.

In addition to the laser source2, the laser light distribution modification unit4and the first and second laser light modification units7,8, the lighting apparatus801comprises a laser light modification unit sensor802for determining the position of at least one of the first and second laser light modification units7,8, a control unit803for controlling the laser light distribution modification unit in such a way that the laser light of the first and second laser light distributions meets at least one of the first and second laser light modification units7,8using the determined position, and a person presence sensor804for determining whether a person is present in the vicinity of the lighting apparatus801. In this embodiment, the control unit803is also adapted to control the lighting apparatus, in particular, the laser source2and/or the laser light distribution modification unit4, in dependence on the determination whether or not a person is present in the vicinity of the lighting apparatus.

In this embodiment, the position of at least one of the laser light modification units7,8can be altered, for example, by hand, wherein the new position of at least one of the laser light modification units7,8can be determined by the laser light modification unit sensor802. The laser light distribution modification unit4can be controlled by the control unit803in such a way that the laser light distribution is modified from a first to a second laser light distribution, wherein light of the second laser light distribution still meets at least one of the first and second laser light modification units7,8in the altered position. The position of a laser light modification unit can thus be identified and tracked by the laser light distribution modification unit which is coupled to the laser light modification unit sensor803, so that laser light tracks and is incident on the laser light modification unit.

The laser light modification unit sensor is, for example, an infrared (IR) sensor, a Lidar sensor, an ultrasonic sensor and/or a radio frequency identification (RFID) sensor for determining the position of a laser light modification unit.

The person presence sensor804is adapted to determine whether a person is present in the vicinity of the lighting apparatus, in particular, in a room, in which the lighting apparatus is located. The person presence sensor804can also be adapted to determine whether a person is moving in the vicinity of the lighting apparatus. This allows modification of the illumination configuration in dependence on the presence of a person or a certain action of the person. The lighting apparatus802can thus be used as an ambient intelligent lighting system.

FIG. 3shows schematically, by way of example, another embodiment of a lighting apparatus101according to the invention.

The lighting apparatus101comprises a laser source2for emitting laser light4. The lighting apparatus101further comprises two beam-splitting units11for splitting the laser light4into at least a first and a second beam. The light from the beam-splitting units11is directed onto laser light modification units82,94. An example of a beam-splitting unit11is schematically shown inFIG. 4in more detail.

InFIG. 4, the laser light3is directed onto a beam splitter17which splits the laser light3into a first beam20and a second beam19. The first beam20is directed onto a laser light modification unit82,94, which can be regarded as a first laser light modification unit or a second laser light modification unit and is assigned to the respective beam-splitting unit11. The laser light modification unit82or94emits modified light15if the first light beam20is directed onto the laser light modification unit82or94, respectively. The second beam19is directed onto another beam-splitting unit11or onto a redirection unit12which directs the second light beam onto a further laser light modification unit18. Alternatively, the second light beam19can be directly directed onto another laser light modification unit.

InFIG. 4, the beam-splitting unit11further comprises an adjustable half-wave plate16for modifying the relative intensity of the first and second light beams with respect to each other. This is, for example, achieved by using the adjustable half-wave plate located in front of the polarizing beam splitter17, so that the light traverses the half-wave plate before impinging upon the beam splitter. In this embodiment, the intensity of the first and the second beam relative to each other can be modified by modifying or adjusting the state or direction of polarization of the light by means of the half-wave plate. Instead of the half-wave plate, another polarization converter or polarization rotator can be used.

Instead of the polarizing beam-splitting mirror17, another polarizing beam-splitting element can be used, such as a beam-splitting cube or a switchable mirror.

An embodiment of a redirection unit12is schematically shown by way of example inFIG. 5.

In this embodiment, the redirection unit12comprises a redirection element80which redirects the incoming laser light81without splitting it, which, in this embodiment, is a second light beam of a beam-splitting unit11, onto a laser light modification unit18which generates modified light13and in particular emits luminescent light if the laser light is directed onto the laser light modification unit18, and which is assigned to the redirection unit12. The mirror80can be replaced by another redirection element such as a reflecting prism. In another embodiment, the redirection element80can be omitted and the incoming laser light81can be directed directly onto the luminescent material82for emitting luminescent light13.

In other embodiments, the redirection element may be a rotating mirror which, for example, can be rotated so that the reflecting angle of the light is changed. An example of a rotating mirror is schematically shown inFIG. 6. In a further embodiment, the redirection element may be a rotating glass plate, an example of which is schematically shown inFIG. 7and which can be rotated in such a way that the direction of the light and/or a parallel shift of the light is modified. The redirection element may also be a liquid crystal element, an example of which is schematically shown inFIG. 8. This redirection element is obtained by placing a wedge-shaped transparent layer92and a liquid crystal material93between transparent substrates90,91provided with transparent electrodes (not shown). Upon application of an electric field, the orientation of the liquid crystal molecules can be altered, thereby changing the effective refractive index of the liquid crystal for changing the direction of the light.

The distribution of the laser light directed onto the laser light modification units can be modified by modifying the relative intensity in at least one of the beam-splitting units11, thereby modifying the illumination configuration of the lighting apparatus101. In this embodiment, the beam splitter17is a polarizing beam splitter which splits the light in dependence on the polarization of the laser light incident on the beam splitter. The intensity of one of the first and second beams can thus be modified relative to the intensity of the other of the first and second beams by modifying the state or direction of polarization of the light impinging upon the beam splitter by means of the half-wave plate16or another optical element, which allows modification of the polarization of the light. The different laser light modification units18,82,94preferably modify the light differently, for example, different laser light modification units may comprise different luminescent materials emitting different luminescent light. For example, the luminescent materials can emit light having different wavelengths. The beam-splitting units11and optionally the redirection unit12can be used for modifying the laser light distribution directed onto the laser light modification units. The beam-splitting units11and optionally the redirection unit12thus constitute a laser light distribution modification unit.

The half-wave plate16is preferably modified by electrical and/or mechanical means which can be used for controlling the half-wave plate automatically, in particular, for modifying the laser light distribution between different predefined laser light distributions in accordance with a predefined schedule, or manually.

Although the lighting apparatus, particularly the laser light modification unit comprises several beam-splitting units11and a redirection unit12in the embodiment described above and illustrated with reference toFIG. 3, the lighting apparatus may comprise only one beam-splitting unit and/or only one redirection unit in other embodiments. Furthermore, in another embodiment, the lighting apparatus may comprise a different number of beam-splitting units and/or redirection units.

The beam-splitting units11and/or the redirection unit12may comprise a casing in which the respective components of the beam-splitting units and the redirection unit are arranged and preferably mounted.

FIG. 9shows schematically, by way of example, another embodiment of a lighting apparatus201.

The lighting apparatus201comprises a laser source2emitting laser light3which is directed onto several beam-splitting units11and a redirection unit12. The laser light3is directed onto several optical switches40, with several laser light modification units95,96,97being assigned to each optical switch40. In this embodiment, each laser light modification unit95,96,97comprises a luminescent material24,25,26and a beam shaper21,22,23, respectively. The luminescent materials24,25,26are preferably materials that absorb the laser light having a certain spectral distribution and emit luminescent light with a spectral distribution which is different from the spectral distribution of the laser light. In other embodiments, the luminescent materials24,25,26can be replaced by transparent materials which do not change the spectral distribution of the laser light. However, the transparent materials may change the direction of the laser light, for example, by scattering. In a further embodiment, the luminescent materials and also the transparent materials are not present in the laser light modification units. The optical switch40is adapted to redirect the laser light3onto one, several or all of the laser light modification units95,96,97assigned to the respective optical switch. Furthermore, the optical switch40is preferably adapted to modify the ratio of the intensities of the laser light directed onto at least one of the laser light modification units95,96,97.

In this embodiment, the beam shapers21,22,23shape the light beam emitted by the respective luminescent material differently. In particular, the beam shaper21generates a beam shape having the smallest divergence, the beam shaper22generates a beam shape having a middle divergence and the beam shaper23generates a beam shape having the largest divergence. The laser light32is directed onto the luminescent material24in such a way that the luminescent light emitted by the luminescent material24has a beam shape with a relatively small divergence. The laser light33is directed onto the luminescent material25in such a way that the beam shaper22generates a beam shape having a middle divergence, and the laser light34is directed onto the luminescent material26in such a way that the beam shaper23generates a beam shape29having the largest divergence. On the right-hand side inFIG. 9, laser light35and laser light36are directed simultaneously onto the luminescent materials24and26in such a way that a beam shape of the luminescent light is generated, which is a combination of the beam shape having a small divergence and the beam shape having a large divergence. The beam shape can thus be modified by directing the laser light onto one or several of the beam shapers21,22,23directly or via luminescent or transparent materials, which may scatter the laser light.

The beam shapers are preferably micro beam-shaping elements.

The collimation of the light can be modified by using the beam shapers.

In one embodiment, the combination of an optical switch40, optionally of the luminescent materials assigned to the respective optical switch and the beam shapers optionally attached to the luminescent materials can be regarded as a single unit within the lighting apparatus. In another embodiment, the lighting apparatus comprises only one of these units. Laser light can be directed directly onto one or several of the optical switches40via the beam-splitting units11and the redirection unit12as schematically shown by way of example inFIG. 9, or via other beam-splitting units and redirection units comprising beam splitters and mirrors. In a further embodiment, the lighting apparatus comprises several of these units, whose number may differ from the number shown inFIG. 9. A single unit or several units can be arranged within a single casing or several casings.

The beam-splitting units11, the redirection unit12and the optical switches40form a laser light distribution modification unit for modifying a laser light distribution directed onto at least one of the laser light modification units95,96,97which can be regarded as several first and second laser light modification units.

FIG. 10shows schematically, by way of example, a further embodiment of a lighting apparatus301.

The lighting apparatus301comprises a light source2emitting laser light3which is directed onto optical switches40via beam-splitting units11and a redirection unit12. Three laser light modification units44,45,46, which are three luminescent materials44,45,46in this embodiment, are assigned to each optical switch40which is adapted in such a way that the laser light can be directed onto one, several or all of these laser light modification units44,45,46. In particular, each luminescent material44,45,46is addressable by using the optical switch40. The different luminescent materials44,45,46emit luminescent light having different colors, i.e. different spectral distributions, particularly different wavelengths. Different colors can be generated by modifying the laser light distribution onto these luminescent materials44,45,46by the optical switch40, wherein the laser light is directed onto one, several or all of the luminescent materials44,45,46. In particular, the optical switch40is adapted to modify the ratio of the intensities of laser light directed onto at least two luminescent materials which are assigned to the same optical switch40. In this embodiment, a beam shaper47for shaping the luminescent light emitted from the luminescent materials44,45,46is attached to a group of three luminescent materials44,45,46, i.e. of three laser light modification units. The light beam41is directed onto the luminescent material44, the light beam42is directed onto the luminescent material45and the light beam43is directed onto the luminescent material46in such a way that, in the laser light distribution shown inFIG. 10, three different light beams having three different colors are emitted. Preferably any color or color temperature of the light emitted by the luminescent materials can be obtained by modifying the laser light distribution, particularly by adjusting the intensities of the laser light incident on the luminescent materials.

The optical switch can be based on at least one of the following components to be arranged in a manner well known to a person skilled in the art so as to provide a desired optical switch: a liquid crystal, an electrical and/or mechanical means such as shutters, beam splitters, mirrors, etc. A beam shaper is, for example, a conical tube having an inner side which is reflecting, particularly totally reflecting for the light, and in which the cone angle corresponds to the collimation of the generated beam shape. A beam shaper may also comprise a parabolic reflector which can produce desired beam shapes with a desired collimation.

The combination of an optical switch, the luminescent materials assigned to the respective optical switch and optionally a beam shaper assigned to the luminescent materials can be regarded as a single color unit. In one embodiment, the lighting apparatus comprises only one of these color units. In a further embodiment, the lighting apparatus may comprise several color units whose number may differ from the three color units shown inFIG. 10. The components of a color unit can be arranged within a color unit casing.

The beam-splitting units11, the redirection unit12and the optical switches40can be regarded as a laser light distribution modification unit which is adapted to modify the laser light distribution directed onto at least one of the laser light modification units44,45,46which can be regarded as first and second laser light modification units. Instead of the beam-splitting units11and the redirection unit12, other beam-splitting elements and redirection elements can be used, for example, simple mirrors and beam splitters. In one embodiment, the laser light distribution modification unit may comprise only a single optical switch40which is directly illuminated by laser light from the laser source2.

A further embodiment of a lighting apparatus is schematically shown by way of example inFIG. 11.

The lighting apparatus401comprises a light source2emitting laser light3which is directed onto optical switches40via beam-splitting units11and a redirection unit12. The lighting apparatus401further comprises several laser light modification units51,52comprising, in this embodiment, luminescent materials51,52assigned, in this embodiment, to each optical switch40, wherein the luminescent material51emits luminescent light having a different color temperature T1than a color temperature T2of the luminescent light emitted by the luminescent material52. The light beam56, which is directed onto the luminescent material51, emits luminescent light53having the color temperature T1. The light beam57, which is directed onto the luminescent material52, emits luminescent light54having the color temperature T2. On the right-hand side inFIG. 11, light beam58is directed onto the luminescent materials51,52simultaneously, thereby generating luminescent light55. The optical switch40is adapted to modify the ratio of the intensities of the light directed onto the luminescent materials assigned to the same optical switch40so that any color temperature between T1and T2can be obtained. In this embodiment, a beam shaper47for shaping the luminescent light generated by the luminescent materials is attached to each combination of the two luminescent materials51,52. This beam shaper47can be omitted.

InFIG. 11, the light beams56,57,58are shown at certain locations. In a preferred embodiment, the optical switch40is adapted to continuously shift the light beams from one location to another location, wherein, in this case, the ratio of the areas on the first luminescent material51and the second luminescent material52illuminated by the light beam from the optical switch40determines the color temperature of the light emitted by the laser light modification units, i.e. the luminescent materials51,52.

The optical switch, the laser light modification units comprising the luminescent materials assigned to the optical switch and optionally also the beam shaper assigned to the luminescent materials define a color unit. The lighting apparatus may comprise only one or several of these color units whose number may differ from the number of three shown inFIG. 10. The components of the color unit can be arranged within a color unit casing.

The beam-splitting units11, the redirection unit12and the optical switches40constitute a laser light distribution modification unit for modifying a laser light distribution directed onto at least one of the laser light modification units which, in this embodiment, comprise the luminescent materials51,52and can be regarded as first and second laser light modification units. In other embodiments, the laser light can be directed directly onto the optical switch40in such a way that this switch can be regarded as a laser light distribution modification unit. In another embodiment, the lighting apparatus may comprise a different number of beam-splitting units, optional redirection units, optical switches and laser light modification units, i.e. luminescent materials51,52.

FIG. 12shows schematically, by way of example, another embodiment of a lighting apparatus.

The lighting apparatus501comprises a light source2emitting laser light3which is directed onto optical switches40via beam-splitting units11and a redirection unit12. The lighting apparatus501further comprises laser light modification units37,38,39each comprising a luminescent material62,63or65and a redirection element61,64or66, respectively. The laser light modification units37,38,39are assigned to the optical switches40adapted to direct the laser light onto one, several or all of the laser light modification units37,38,39, particularly of the luminescent materials62,63,65. A redirection element61,64,66is assigned to several of the luminescent materials62,63,65, in particular, to each luminescent material62,63,65, while different redirection elements are assigned to different luminescent materials62,63,65assigned to the same optical switch so that luminescent light emitted from different luminescent materials of different laser light modification units37,38,39assigned to the same optical switch is directed into different directions. For example, luminescent light emitted by the luminescent material62is directed into the direction72by the redirection element61, luminescent light emitted by the luminescent material63is directed into the direction73by the redirection element64, and luminescent light emitted by the luminescent material65is directed into the direction74by the redirection element66. The light beam67is directed onto the luminescent material62which is directed into the direction72by the redirection element61. The light beam68is directed onto the luminescent material63which emits luminescent light directed into the direction73by the redirection element64, and the light beam69is directed onto the luminescent material65which emits luminescent light directed into the direction74by the redirection element66. On the right-hand side inFIG. 11, the optical switch40directs light beams70and71simultaneously onto luminescent materials so that luminescent light is emitted, which is directed into a combined direction by the redirection elements61and66assigned to the luminescent materials62,65onto which the light beams70,71are directed. The direction of the luminescent light emitted by the luminescent materials can be modified by modifying the laser light distribution directed onto the laser light modification units by means of the laser light distribution modification unit which, in this embodiment, is constituted by the optical switch40, the beam-splitting units11and the redirection unit12. The optical switch40can direct the laser light onto one, several or all luminescent materials of the laser light modification units assigned to the respective optical switch. Furthermore, the optical switch is adapted to modify the ratio of the intensities of the light beams directed onto at least two luminescent materials of the laser light modification units assigned to the same optical switch, in order to modify the direction of the luminescent light emitted by at least two of the luminescent materials61,63,65.

Instead of or in addition to the luminescent materials, the laser light modification units may comprise another material or no material at all, the other material being preferably a non-absorbing material. It is further preferred that this other material is a light-scattering material which changes the direction of the laser light by scattering it.

The combination of an optical switch, the luminescent materials assigned to the optical switch and the redirection elements assigned to the luminescent materials can be regarded as a single redirection unit. The lighting apparatus may comprise only one or several of these redirection units whose number may differ from that shown inFIG. 12. The components of the single redirection unit or of several redirection units can be arranged within a redirection unit casing.

The beam-splitting units11, the redirection unit12and the optical switches40constitute a laser light distribution modification unit for modifying the laser light distribution directed onto at least one of the laser light modification units37,38,39which can be regarded as first and second laser light modification units. If, in other embodiments, the laser light3is directed directly onto the optical switch40, this switch can be regarded as a laser light distribution modification unit. Instead of the beam-splitting units11and/or the redirection unit12, other elements for beam-splitting and redirecting a beam can be used, for example, mirrors and/or beam splitters. The example of the lighting apparatus501schematically shown inFIG. 12may comprise a different number of beam-splitting units11, redirection units12, optical switches40, laser light modification units37,38,39, luminescent materials and redirection elements within a laser light modification unit.

A further embodiment of a lighting apparatus601is schematically shown by way of example inFIG. 13.

The lighting apparatus601comprises a laser source2emitting laser light3which is directed onto optical switches40via beam-splitting units11and a redirection unit12. The optical switches40are adapted to direct the laser light onto at least one of several laser light modification units98,99,100each comprising one of several luminescent materials91,92,93and one of several beam shapers80,81,82directed into different directions and preferably attached to the luminescent materials91,92,93. In particular, a beam shaper80,81,82is assigned and preferably attached to each luminescent material91,92,93. If the light beam76is directed onto the luminescent material92, the beam shaper81shapes the beam and directs the same into the direction83. If the optical switch40directs the light77onto the luminescent material91, the luminescent light is shaped and directed by the beam shaper80into the direction84, and if the light beam78is directed onto the luminescent material93, luminescent light is generated, which is shaped by the beam shaper82and directed into the direction85. On the right-hand side inFIG. 12, the optical switch40directs the laser light onto three luminescent materials91,92,93simultaneously, generating luminescent light which is directed into the direction86. The optical switch40can direct the laser light onto one, several or all luminescent materials of the laser light modification units assigned to the respective optical switch. Furthermore, the optical switch40is adapted to modify the ratio of the intensities of the laser light directed onto at least two different luminescent materials. The optical switch40, which can be regarded as a component of the laser light distribution modification unit, can thus modify the laser light distribution, and the shape and/or direction of the luminescent light emitted by the luminescent materials can be modified by modifying this laser light distribution.

The laser light modification units98,99,100may comprise another material or no material instead of the luminescent materials91,92,93. For example, materials which do not change the spectral distribution of the laser light but rather change, for example, its direction, for example, by scattering can be used instead of the luminescent materials.

The combination of an optical switch and the laser light modification units, which preferably comprise the luminescent materials and the beam shapers assigned to the optical switch, constitutes a single beam-shaping and redirection unit, in which the lighting apparatus may comprise one or several of these beam-shaping and redirection units, and in which the number of beam-shaping and redirection units may differ from that shown inFIG. 13. The components of a single beam-shaping and redirection unit or of several beam-shaping and redirection units can be arranged within a beam-shaping and redirection unit casing.

In this embodiment, the beam-splitting units11, the redirection unit12and the optical switches44constitute a laser light distribution modification unit for modifying the laser light distribution directed onto at least one of the laser light modification units98,99,100which can be regarded as first and second laser light modification units. If, in other embodiments, the laser light is directed directly onto the optical switches, this switch is regarded as the laser light distribution modification unit. In one embodiment, the laser light distribution modification unit comprises only the optical switch40for modifying the laser light distribution directed onto at least one of several laser light modification units. In further embodiments, the number of beam-splitting units11, redirection unit12, optical switches40, laser light modification units98,99,100and the number of luminescent materials91,92,93and beam-shaping and redirection elements80,81,82may differ from the numbers shown inFIG. 13. These numbers, which may be different from those shown inFIG. 13, may also be zero.

An embodiment of a lighting method will now be described by way of example with reference to a flowchart shown inFIG. 14.

In step701, laser light3is emitted by a laser source2.

In step702, the laser light is directed onto at least one of a first and a second laser light modification unit, the first laser light modification unit7being situated at a first location and adapted to modify the optical characteristic of the laser light. It preferably comprises a first luminescent material for emitting first luminescent light9if the laser light3,5is directed onto the first laser light modification unit. The spectral distribution of the first luminescent light9is different from that of the laser light3,5. The second laser light modification unit8is situated at a second location and is adapted to modify an optical characteristic of the laser light. It preferably comprises a second luminescent material for emitting second luminescent light10if the laser light3,6is directed onto the second laser light modification unit8. The spectral distribution of the second luminescent light10is different from that of the laser light3,6.

In step703, a laser light distribution defined by the laser light directed onto at least one of the first and second laser light modification units7,8is modified by the laser light distribution modification unit4from a first to a second laser light distribution which is different from the first laser light distribution.

The luminescent materials are preferably phosphor materials, in particular, organic and/or inorganic phosphor materials. The luminescent materials are preferably materials which can be excited by blue and/or violet light, in particular by light having a wavelength within a range of 405 to 470 nm. The luminescent materials preferably convert the laser light into white light or light having a different color. The luminescent materials are preferably supported on a supporting element, which is preferably a supporting plate and is transmissive to the luminescent light emitted by the luminescent materials. The supporting plate is preferably a glass plate. The supporting element is preferably also a part of the lighting apparatus. The luminescent material is preferably provided as a luminescent layer on the supporting element.

If the components of the lighting apparatus, i.e. at least the laser source, the laser light modification units and the laser light distribution modification unit, are located substantially within the same plane, the above-described modification of the direction of the luminescent light by modifying the laser light distribution is preferably performed in such a way that the direction of the luminescent light can be modified between a total edge emission, a top emission and a bottom emission, the top and bottom emissions defining a light emission outside plane in which the components of the lighting apparatus are substantially located, and the total edge emission defining a direction of the luminescent light within this plane.

Certain optical elements such as mirrors, beam splitters, half-wave plates etc. are used in the embodiments described above. In other embodiments, other optical elements such as a diaphragm can be used alternatively or in addition, while the aperture diameter of the diaphragm can be modified so as to modify the diameter of the laser light directed onto at least one of the first and second laser light modification units. The half-wave plates may be passive or active half-wave plates, and polarizing reflectors may be used, for example, to modify the intensity of the light directed onto the luminescent materials. The optical elements can be arranged in a micro-electromechanical system (MEMS) on a substrate or on a chip.

The laser light distribution modification unit can be adapted in such a way that it only comprises non-moving elements which are preferably based on liquid crystals as schematically shown by way of example inFIG. 8. The use of non-moving elements only allows modification of the laser light distribution from a first to a second laser light distribution without moving an element of the laser light distribution modification unit. The liquid crystals are based on, for example, wedge-shaped liquid crystal elements or elements in which a refractive index gradient is formed within the liquid crystal.

The light source may be any source that emits laser light, particularly usable for exciting luminescent materials in such a way that they emit luminescent light. The light source is preferably a laser which emits blue and/or violet light.

All components of the lighting apparatus are preferably arranged within a casing.

The luminescent material is preferably arranged in points or dots.

Although the lighting apparatus comprises a certain number of optical elements, different units such as beam-splitting units or redirection units, or luminescent materials in the embodiment described above, the number of optical elements, units, luminescent materials and other components of the lighting apparatus may be different in other embodiments.

In the claims, use of the verb “comprise” and its conjugations does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.