EP4777751A1

EP4777751A1 - Efficient (filament) bulb with an optical filter

Info

Publication number: EP4777751A1
Application number: EP24768011.9A
Authority: EP
Inventors: Martinus Arnoldus Cornelis HEIJMANS; Martinus Petrus Joseph PEETERS; Victoria Eugenia MUNTANER VALBUENA; Aldegonda Lucia WEIJERS
Original assignee: Signify Holding BV
Current assignee: Signify Holding BV
Priority date: 2023-09-14
Filing date: 2024-09-03
Publication date: 2026-07-22
Also published as: WO2025056359A1; CN121816478A

Abstract

The invention provides a light generating system (1000) comprising (i) one or more first light generating devices (110), one or more second light generating devices (120), a light transmissive enclosure (500), and an optical filter (550), wherein: (I) the light transmissive enclosure (500) comprises a light transmissive material (505), wherein the light transmissive enclosure (500) comprises an upstream face (501) and a downstream face (502); wherein the light transmissive enclosure (500) defines an enclosure volume (507); (II) the one or more first light generating devices (110) are at least partly configured in the enclosure volume (507); wherein the one or more first light generating devices (110) are configured to generate first device light (111) having intensity at one or more wavelengths in the visible wavelength range; wherein the one or more first light generating devices (110) comprise one or more LED filaments (115) (and wherein the first device light (111) comprises filament light); (III) the one or more second light generating devices (120) comprise one or more solid state light sources; wherein the one or more second light generating devices (120) are configured to generate second device light (121) having intensity at one or more wavelengths in the visible wavelength range, including at least one or more wavelengths in the blue-green wavelength range; (IV) the optical filter (550) comprises a dichroic filter; wherein the optical filter (550) is configured within the enclosure (500); wherein the optical filter (550) is transmissive for at least part of the first device light (111) and reflective for at least part of the second device light (121) (in the blue-green wavelength range); wherein the one or more second light generating devices (120) are configured such that at least part of the second device light (121) ) (in the blue-green wavelength range) is reflected at the optical filter (550) in a direction away from the one or more first light generating devices (110); and (V) the light generating system (1000) is configured to generate system light (1001) comprising one or more of (i) at least part of the first device light (111), and (ii) at least part of the second device light (121); and wherein the light generating system (1000) is configured such that in a first operational mode of the light generating system (1000) the system light (1001) is white light having a correlated color temperature in a range from 1500K to 6500K.

Description

Efficient (filament) bulb with an optical filter

FIELD OF THE INVENTION

The invention relates to a light generating system. The invention further relates to a lighting device comprising the light generating system.

BACKGROUND OF THE INVENTION

Light generating systems are known in the art. US2012236595A1 describes a light bulb including a base, a light guide having opposed major surfaces between which light propagates by total internal reflection, a light input edge, and two light output regions of different optical characteristics at least one of which is associated with a corresponding one of the major surfaces, and a light source electrically coupled to the base and located adjacent the light input edge. The light source and the light guide are variably positionable relative to one another to vary a location on the light input edge at which light is input to the light guide such that light is emitted from the light guide selectively apportioned between the light output regions so that a characteristic of the light output from the light bulb is modified based on the optical characteristics associated with the light output regions and the relative positioning of the light source and the light guide.

SUMMARY OF THE INVENTION

While solid state light sources may have a high efficiency, the efficiency of light generating systems comprising said solid state light sources may be relatively low. Hence, it is desired to improve the energy efficiency of the light generating system, especially a higher lumen output at a low wattage is desired. Further, it may be desired to control the spectral properties of outcoupled light in the color space with good color rendering. Furthermore, it may be desired to control the brightness/dimmability of the outcoupled light.

Hence, it is an aspect of the invention to provide an alternative light generating system, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. According to a first aspect, the invention provides a light generating system comprising one or more first light generating devices, one or more second light generating devices, a light transmissive enclosure (or “envelope”), and an optical filter. In embodiments, the light transmissive enclosure may comprise a light transmissive material. Further, the light transmissive enclosure may in embodiments comprise an upstream face and a downstream face. Furthermore, in embodiments, the light transmissive enclosure may define an enclosure volume (“first enclosure volume”). In embodiments, the one or more first light generating devices may at least partly be configured in the enclosure volume. Especially, the one or more first light generating devices may be configured to generate first device light having intensity at one or more wavelengths in the visible wavelength range. In further embodiments, the one or more first light generating devices may comprise one or more first light emitting diode (LED) filaments (or one or more phosphor covered LEDs, or one or more (phosphor covered) COBs, or a combination of two or more of LED filaments, (phosphor covered) phosphor covered LEDs, and COBs). Especially, the first device light may comprise filament light. In embodiments, the one or more second light generating devices may comprise one or more solid state light sources. Especially, the one or more second light generating devices may be configured to generate second device light having intensity at one or more wavelengths in the visible wavelength range. More especially, the one or more second light generating devices may be configured to generate second device light comprising one or more wavelengths in the blue-green wavelength range. In embodiments, the optical filter may comprise a dichroic filter. Especially, the optical filter may be configured within the enclosure. Further, the optical filter may in embodiments be transmissive for at least part of the first device light and reflective for at least part of the second device light (in the blue-green wavelength range). In embodiments, the one or more second light generating devices may be configured such that at least part of the second device light (in the blue-green wavelength range) may be reflected at the optical filter in a direction away from the one or more first light generating devices. In embodiments, the light generating system may be configured to generate system light comprising one or more of (i) at least part of the first device light, and (ii) at least part of the second device light. Especially, the light generating system may be configured such that in a first operational mode of the light generating system the system light is white light. More especially, the system light may be white light having a correlated color temperature in a range from 1500- 6500 K, such as 1700 K to 6500 K. In specific embodiments, the invention provides a light generating system comprising one or more first light generating devices, one or more second light generating devices, a light transmissive enclosure, and an optical filter, wherein: (I) the light transmissive enclosure comprises a light transmissive material, wherein the light transmissive enclosure comprises an upstream face and a downstream face; wherein the light transmissive enclosure defines an enclosure volume; (II) the one or more first light generating devices are at least partly configured in the enclosure volume; wherein the one or more first light generating devices are configured to generate first device light having intensity at one or more wavelengths in the visible wavelength range; wherein the one or more first light generating devices comprise one or more first LED filaments (and wherein the first device light comprises filament light); (III) the one or more second light generating devices comprise one or more solid state light sources; wherein the one or more second light generating devices are configured to generate second device light having intensity at one or more wavelengths in the visible wavelength range, including at least one or more wavelengths in the blue-green wavelength range; (IV) the optical filter comprises a dichroic filter; wherein the optical filter is configured within the enclosure; wherein the optical filter is transmissive for at least part of the first device light and reflective for at least part of the second device light in the blue-green wavelength range; wherein the one or more second light generating devices are configured such that at least part of the second device light in the bluegreen wavelength range is reflected at the optical filter in a direction away from the one or more first light generating devices; and (V) the light generating system is configured to generate system light comprising one or more of (i) at least part of the first device light, and (ii) at least part of the second device light; and wherein the light generating system is configured such that in a first operational mode of the light generating system the system light is white light having a correlated color temperature in a range from 1500-6500 K, such as 1700 K to 6500 K.

With such a light generating system a higher energy class (i.e., a higher efficiency) light generating system may be provided. Here, the light generating system may increase the light intensity without a proportional increase in power consumption. Hence, a higher (lumen) output at a lower power wattage may be provided. Further, the present light generating system may tune the hue (or color) of the outcoupled light by using one or more different tunable white and RGB light sources in combination with a white light source. Further, to prevent optical cross-talk, between the blue light sources and the white light generating devices, like in embodiments LED filaments, the optical filter may comprise a material that reflects the blue light. Furthermore, the light generating system may be configured dimmable by dimming the individual light generating devices comprised by the light generating system. Hence, a light generating system with high lumen output to wattage, color tunability and dimmability may be provided. Therefore, in embodiments, the invention may provide an efficient (filament) bulb with an optical filter, such as a dichroic coating, e.g. on the inside of an enclosure.

As mentioned above, in embodiments, the invention provides a light generating system configured to generate system light. In embodiments, the light generating system may comprise one or more first light generating devices, one or more second light generating devices, a first light transmissive enclosure, and an optical filter. Here below, a general description of the invention is provided followed by some embodiments.

In embodiments, the one or more first light generating devices and/or the one or more second light generating devices) may comprise solid state light sources. The solid state light sources are especially configured to generate (solid state) light source light. The one or more first light generating devices and/or the one or more second light generating devices may comprise an LED, especially a phosphor covered LED. In further embodiments, the first light generating device and/or the second light generating device may comprise one or more of: (i) a chip-on-board (COB) light source and (ii) an LED filament. A COB may be a multi LED chip configured together as a single lighting module. See also below.

In specific embodiments, the one or more first light generating devices may comprise one or more first LED filaments. Further, in specific embodiments, the one or more second light generating devices may comprise one or more second LED filaments.

In embodiments, a LED filament may comprise an array of a plurality of solid state light sources (such as LEDs) arranged on (a first major surface of) an elongated carrier, wherein an (elongated) encapsulant is covering the plurality of solid state light sources (such as LEDs) and at least part of (said major surface of) said elongated carrier, wherein the encapsulant may comprise the luminescent body. Especially, in embodiments, the luminescent body may be configured as an elongated encapsulant covering the plurality of solid state light sources (such as LEDs) and at least part of the elongated carrier. Especially, the encapsulant may cover essentially the entire elongated carrier.

The luminescent material may especially convert at least a part of the light source light into luminescent material light. Furthermore, a part of the light source light may be transmitted (unconverted) via the luminescent material. Hence, in embodiments, outcoupled LED filament light may comprise the luminescent material light and optionally the (unconverted) light source light. For instance, the luminescent material may convert (a part of) blue light source light into yellow luminescent material light. Here, the outcoupled LED filament light may in embodiments be white light comprising light in the blue wavelength range (from the solid state light source(s)) and yellow wavelength range (from the luminescent material). In general, the luminescent material light may have a spectral power distribution at larger wavelengths than the light source light, which may be referred to as “down-conversion”. The material composition of the luminescent material used in embodiments is described further below.

Further, LED filaments may in embodiments be configured into different shapes. In embodiments, the LED filaments may be rectilinear and elongated in one direction. Additionally or alternatively, the LED filaments may (be elongated, but) also be coiled or comprise a spiral-like shape, such as a helical shape. The advantage of a coiled configuration may be that a coiled filament is longer than a rectilinear filament and hence more light sources (e.g., COB or LED) may be configured on the filament (compared to a rectilinear filament). Furthermore, a relatively large beam angle may be provided, such as a (relatively large) beam angle of the LED filament light.

In embodiments, the one or more first light generating devices may generate the first device light. As can be derived from the above, especially the first device light may comprise first filament light (and/or COB light (i.e. light from a COB). In embodiments, the one or more second light generating devices may generate the second device light. In some embodiments, the second device light may comprise second filament light (and/or COB light (i.e. light from a COB). In embodiments, spectral power distributions of the first device light and the second device light may differ, see also below.

In embodiments, the first light transmissive enclosure may comprise a first enclosure wall. The term “first enclosure wall” especially refer to the wall of the first enclosure. The first light transmissive enclosure (especially the first enclosure wall) may especially comprise a first upstream face and a first downstream face. Note that the terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here especially the first light generating device), wherein relative to a first position within a beam of light from the light generating means (i.e., the first light generating device), a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”. The first light transmissive enclosure may in embodiments (at least partly) define a first enclosure volume. Especially, the first enclosure volume may be defined partly by the first enclosure wall and may comprise a first enclosure opening which may be functionally coupled to a support. The light transmissive enclosure may further comprise a first enclosure edge connecting the first upstream face and the first downstream face. Furthermore, the opening to the first enclosure volume may be bounded by the first enclosure edge.

The term “within” or “inside” the first light transmissive enclosure may refer to a region of space at least partly enclosed by the first light transmissive enclosure. Especially, the one or more elements configured “within” the first light transmissive enclosure may be configured on the support in a position upstream of the first upstream face. Analogously, the term “outside” the first light transmissive enclosure may refer to a region of space not enclosed by the first light transmissive enclosure.

Hence, the light generating system may comprise a support. Especially, the one or more first light generating devices and/or the one or more second light generating devices may be functionally coupled to the support. Especially, the support is configured to support the one or more first light generating devices and/or the one or more second light generating devices. Further, the support may support one or more of a driver, a control system, etc.

Note that, in (certain) embodiments, the first light transmissive enclosure may not enclose the one or more second light generating devices. That is, in embodiments, the one or more second light generating devices may be configured outside the first light transmissive enclosure. However, in some other embodiments, the second light generating devices may (also) be configured within the first light transmissive enclosure, such embodiments are described later.

In embodiments, the first light transmissive enclosure may have a shape/geometry resembling a dome. That is, in embodiments, the first light transmissive enclosure may have a bell-like shape, a bulb-like, a cloche-like shape, a hemispherical shape, etc. In further embodiments, the first light transmissive enclosure may (also) have a tubular shape with one open end and another flat end (or alternatively a tubular shape with one open end and another dome-like shape end). Furthermore, in some embodiments, the first light generating enclosure may form a hermetic seal (i.e., especially substantially watertight, more especially substantially airtight) with the support and thus, protect the light generating device from the ingress of dust, dirt and pollutants. For instance, in embodiments the first light transmissive enclosure together with the support may provide a (first) enclosure volume with an IP44 or higher classification. However, other embodiments may thus also be possible.

The first light transmissive enclosure may in embodiments comprise a first light transmissive material. The term “light transmissive” refers to the optical property of a medium to be transmissive for light incident on said medium. Especially, the first light transmissive enclosure may transmit 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100% of the first device light when perpendicularly incident on the first light transmissive enclosure. Hence, the first light transmissive enclosure may especially be transmissive for incident first device light, and first device light may escape via the first light transmissive enclosure. More especially, in embodiments the first light transmissive enclosure as such (i.e. not taking into account the optical filter) may be transparent for first device light.

In further embodiments, the first enclosure wall may be configured as a light guide. Especially, the first light transmissive material comprised by the first light transmissive enclosure may facilitate light guiding the second device light. To facilitate incoupling of second device light into the first enclosure wall of the first light transmissive enclosure, in embodiments, the second light generating devices may be configured upstream from the first enclosure edge. “Light guiding” may refer to the propagation of light within the enclosure wall, especially by means of total internal reflection. In specific embodiments, the first light transmissive enclosure comprises a first enclosure edge; wherein the first enclosure edge of the first light transmissive enclosure is configured in a light-receiving relationship with the one or more second light generating devices; and wherein the first light transmissive enclosure and the one or more second light generating devices are configured such that at least part of the second device light escapes from the downstream face after multiple reflections within the first light transmissive material (and wherein the one or more second light generating devices are (thus) configured upstream from the first downstream face). Hence, in embodiments the first light transmissive enclosure as such (i.e. not taking into account the optical filter) may be transparent for second device light.

The first enclosure wall may comprise light scattering structures configured to facilitate that (second device) light may escape from the first enclosure wall. Optionally, the second enclosure wall may comprise scattering structures. Scattering structures may comprise one or more of (embedded) scattering particles and surface scattering structures.

In embodiments, the first enclosure wall and/or the second enclosure wall may comprise geometrical surface structures configured to scatter incident light. The surface structures may be configured in or a with a surface of the first light transmissive enclosure. Here, the second device light (and optionally the first device light) may especially be scattered by the surface scattering structures. Hence, in embodiments, the first light transmissive enclosure may comprise light scattering structures (for example scattering dots or indentations) configured on one or more of the first upstream face and the first downstream face. Also in this way, the second device light (and optionally the (diffuse) first device light) may be coupled out from the first enclosure wall.

Further, in embodiments, the first enclosure wall may comprise scattering particles. Especially, the scattering particles may be embedded within the first enclosure wall. Here, the second device light (and optionally the first device light) may especially be scattered by the scattering particles. In embodiments, the light scattering particles may comprise one or more of BaSCU, SiCE, and TiCE. However, (other) particulate (white) pigments may also be applied. The light scattering particles may comprise a difference in the refractive index compared to the host material i.e., the material of the first light transmissive enclosure. In this way, diffuse second device light (and optionally diffused first device light) may especially be outcoupled from the (first) enclosure wall.

As the first light generating device may comprise a luminescent material that may be excited by the second device light of a second light generating device, especially one providing light in the blue wavelength range and/or the green wavelength range, the spectral power distribution of the system light may undesirably be affected. Hence, in embodiments, the light generating system may comprise an optical filter. Especially, the optical filter may be selectively transmissive for at least part of the first device light and reflective (or alternatively absorptive) for at least part of the second device light. Furthermore, in embodiments, the optical filter may at least partially enclose one or more of the first light generating devices. In specific embodiments, the optical filter may be arranged in a tubular configuration, at least partly enclosing the one or more first light generating devices. Alternatively, in embodiments, the optical filter may completely enclose the one or more first light generating devices. In such embodiments, the first device light may only escape (to the external of the optical filter completely enclosing the one or more first light generating devices) via the optical filter. In embodiments, the optical filter may in embodiments be configured within the first light transmissive enclosure. Especially, the optical filter may be configured upstream of the first upstream face or downstream of the first downstream face. More than one optical filter may also be possible. In specific embodiments, the optical filter may be configured within the first light transmissive enclosure at a (predefined) distance di from the first upstream face , wherein the optical filter may at least partially enclose the one or more first light generating devices.

Additionally or alternatively, in embodiments, the optical filter may be configured on at least a part of the first upstream face (in such embodiments, di would be 0). In further embodiments, the optical filter may comprise a coating applied on at least a part of (such as essentially all of) the first upstream face (or the downstream face) of the first light transmissive enclosure. Combinations may also be possible.

Further, it will be apparent to the skilled person that, in embodiments, the light generating system may also comprise a plurality of optical filters (at least partly configured between on the one hand the one or more first light generating devices and on the other hand the one or more second light generating devices).

As mentioned above, the optical filter may be selectively transmissive for at least part of the first device light and reflective (or alternatively absorptive) for at least part of the second device light. Therefore, in embodiments, the optical filter may be configured between the first light generating devices and the second light generating devices.

In embodiments, the optical filter may comprise a dichroic filter. In other embodiments, the optical filter may comprise an absorption filter. Combinations may also be applied.

A dichroic filter may especially be transmissive for light of a certain wavelength range and be reflective for light of another wavelength range. Especially, the dichroic filter may at least be partly reflective for part of the second device light. As blue light, or optionally green light may excite the luminescent material, especially, the dichroic filter may be reflective for second device light comprising light having intensity in the bluegreen wavelength range (especially at least in the blue wavelength range).

An absorption filter may be transmissive for a certain wavelength range and absorptive for light of another wavelength range. Especially, the absorption filter may be configured to absorb at least part of the second device light, especially light in the blue-green wavelength range. That is, the absorption filter may be absorbing for second device light comprising light having intensity in the blue-green wavelength range (especially at least in the blue wavelength range).

The dichroic filter and/or the absorption filter may in embodiments be applied as a coating on the surface of the first light transmissive enclosure. Alternatively, the optical filter (i.e., comprising the dichroic filter and/or the absorption filter) may be a coating applied on a light transmissive material configured in (close) proximity to the first light transmissive enclosure. Especially, the dichroic filter is (essentially) transparent for one or more wavelengths and (essentially) reflective for one or more other wavelengths (in the blue-green wavelength range). Especially, the absorption filter is (essentially) transparent for one or more wavelengths and (essentially) absorbing for one or more other wavelengths (in the bluegreen wavelength range).

The optical filter (comprising the dichroic filter or the absorption filter) may especially provide the advantage of filtering out undesired wavelengths of the second device light from irradiating the first luminescent material. Especially, the optical filter may reflect (or absorb) (at least a part of) the second device light. Thus, preventing the first luminescent material from being irradiated by the second device light that may generate luminescent material light. For example, the first luminescent material may convert light in the blue wavelength range into yellow light and therefore, it may be desirable to filter out blue wavelength range comprised by the second device light. Hence, in further embodiments, the optical filter may be reflective for a part of the wavelength range of the second device light, such as the part of the second device light comprising light selected from the blue-green wavelength range. Additionally or alternatively, in further embodiments, the optical filter may yet be transmissive for a part of the wavelength range of the second device light, such as the part of the second device light comprising light other than in the blue-green wavelength range. For example, in some embodiments, the optical filter may yet be transmissive for second device light in the red-orange wavelength range.

Hence, in embodiments the optical filter may be less-transmissive for a first wavelength range 380 nm - XI and more transmissive for a second wavelength range XI - 780 nm. Defining the transmissiveness as the wavelength averaged transmission over the respective wavelengths, assuming perpendicular irradiation, the optical filter may have a ratio T1/T2, wherein T1 is the wavelength averaged transmission of the optical filter over the wavelength range 380 nm - XI, and wherein T2 is the wavelength averaged transmission of the optical filter over the wavelength range XI - 780 nm. Especially, Tl/T2<0.5. Further, in specific embodiments Tl/T2<0.2, like Tl/T2<0.1. In specific embodiments, T1/T2 may be essentially zero. Further, XI may be selected from the range of 450-550 nm, such as selected from the range of about 470-530 nm. For instance, XI may be selected from the range of 485- 520 nm. In embodiments, XI may be a cut-off wavelength of an optical filter.

Note that, in embodiments, the first device light may be white light and the optical filter may especially filter out a part of the blue-green wavelength range of the first device light (and the second device light). Therefore, assuming the first device light to be cool white light, the first device light transmitted via the optical filter may be (relatively) warm white light. Hence, in specific embodiments, the first device light may have intensity in the blue-green wavelength range, wherein at least one of the one or more first LED filaments and the optical filter may be configured such that in the first operational mode of the light generating system the system light may be white light consisting of first device light.

Herein, the term “blue green” may in embodiments refer to light having a wavelength selected from blue-green wavelength, i.e. selected from the 440-560 nm wavelength range. Such light may in embodiments be blue, green, or comprise both colors. Note that white light may also have spectral intensity in the blue-green wavelength range.

In alternative embodiments, the first device light may be off-white light, having a relatively high blue content. Due to the optical filter, first device light may be reduced in blue content, leading to device light that may be warm white light, or even cool white light. In such embodiments, 0.1<Tl/T2<0.75, such as 0.25<Tl/T2<0.75, like 0.35<Tl/T2<0.5 may be useful, though other values are herein not excluded.

Especially, an optical filter configured between the one or more first light generating devices and the one or more second light generating devices may thus reduce the amount of second device light incident on the first luminescent material. As a result, optical crosstalk may be reduced, wherein the term “optical crosstalk” may refer to emission of first luminescent material light (by the first luminescent material) upon irradiation with (especially blue-green) second device light.

Further, to provide the desired spectral power distribution of the system light, the second device light may be admixed to the transmitted first device light. Hence, in this way, the spectral power distribution (and e.g. CCT and/or color rendering index (CRI) of the system light may especially be controlled in one or more operational modes of the light generating system. Hence, in (other) specific embodiments, the light generating system is configured such that in the first operational mode of the light generating system the system light is white light comprising at least part of the first device light and at least part of the second device light (wherein the second device light comprises intensity in the blue wavelength range). Hence, in one or more operational modes, the ratio of the amount of first device light to the amount of second device light in the system light may be controlled.

The light generating system may be operated in one or more “modes of operation” or “operational modes”. In embodiments, the light generating system may be configured in a first operational mode to generate the system light that is white light. The term “white light” herein, is known to the person skilled in the art. It especially relates to light having a correlated color temperature (CCT) between about 1500 K and 20000 K, such as between 1700 and 20000 K, especially in embodiments 2700-20000 K, for general lighting especially in the range of about 1800 K and 6500 K. Yet further, in embodiments the correlated color temperature (CCT) is especially within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), especially within about 10 SDCM from the BBL, even more especially within about 5 SDCM from the BBL. In embodiments, the light generating system may be configured to provide in the first operational mode of the light generating system, system light having a correlated color temperature selected from the range 1500-6500 K, such as selected from the range of 1500-3000 K, like selected from the range of 1700-2700 K, though other values may also be possible. As indicated above, the system light may comprise first device light, and optionally second device light. In other operational modes, the system light may only comprise second device light.

Hence, the light generating system may generate in one or more operational modes, system light comprising a range of CCTs (i.e., Tl, T2, etc.). In specific embodiments, the light generating system may be configured to provide in the first operational mode of the light generating system, system light having a correlated color temperature selected from the range of Tl - T2. Especially, |Tl-T2|>200 K, such as |Tl-T2|>500 K. In (other) embodiments, especially |T 1 -T2|>1000 K.

The CCT may be controlled in various ways. In embodiments, by controlling a contribution of the second device light to spectral power distribution of the system light, the CCT may be controlled (see also above). Alternatively or additionally, the CCT may be controlled by applying two or more different first light generating devices, wherein at least two of these two or more first light generating devices generate first device light having different CCTs. Hence, by controlling the contribution of the first device light of the different first devices to the spectral power distribution of the system light, the CCT may be controlled. For instance, a primary first device may be configured to generate first device light having a primary CCT Ti and a secondary first device may be configured to generate first device light having a secondary CCT T2, wherein |T 1 -T2|>500 K. In (other) embodiments, especially |T 1 -T2|>1000 K. Hence, in specific embodiments, the one or more first LED filaments are configured to generate first device light having a correlated color temperature selected from the range of 1500-6500 K; wherein the light generating system comprises at least two different types of first LED filaments configured to generate first device light having correlated color temperatures differing at least 500 K (such as in embodiments at least 1000 K).

In further embodiments (see also above), the light generating system may be configured to generate in a second operational mode of the light generating system non-white system light. Especially, the light generating system may be configured to generate (in such second operational mode) colored system light, like one or more of blue, green, yellow, orange, and red light (including e.g. violet light or cyan light, etc).

As indicated above, the one or more first light generating devices may be configured to generate white light. However, especially the one or more second light generating devices may be configured to generate colored light, respectively. However, it is herein in embodiments also possible that a second light generating device is configured to generate white light, or two or more second light generating devices are configured to provide together white light; see further also below.

In embodiments, the light generating system may comprise a first type of second light generating devices configured to generate first type of second device light having a first centroid wavelength in the blue wavelength range. The term “centroid wavelength”, also indicated as c, is known in the art, and refers to the wavelength value where half of the light energy is at shorter and half the energy is at longer wavelengths; the value is stated in nanometers (nm). It is the wavelength that divides the integral of a spectral power distribution into two equal parts as expressed by the formula Ac = X I(k) / (S I( X)), where the summation is over the wavelength range of interest, and 1(A) is the spectral energy density (i.e. the integration of the product of the wavelength and the intensity over the emission band normalized to the integrated intensity). The centroid wavelength may e.g. be determined at operation conditions.

Additionally or alternatively, in embodiments, the light generating system may comprise a second type of second light generating devices configured to generate second type of second light having a second centroid wavelength in the green wavelength range.

In further embodiments, the light generating system may comprise both the first type of second light generating devices and the second type of second light generating devices. Analogously, in embodiments, the optical filter may be reflective (or absorptive) for one or more of the first type of second device light and the second type of second device light. Whether or not the optical filter should also filters out at least part of the second type of second device light, i.e. especially at least part of the green light, may depend upon the luminescent material. Some luminescent materials may essentially only absorb light in the blue wavelength range, and not in the green wavelength range. Hence, then a cut-off wavelength of the optical filter (see also above) may be at smaller wavelengths than when a luminescent material is available that may also absorb light in at least part of the green wavelength range. Hence, in specific embodiments, the light generating system comprises one or more of (i) a first type of second light generating devices configured to generate first type of second device light having a first centroid wavelength in the blue wavelength range, wherein the optical filter is reflective for at least part of the first type light (wherein the second device light comprises the first type of second device light), and (ii) a second type of second device light generating devices configured to generate second type of second device light having a second centroid wavelength in the green wavelength range, wherein the optical filter is optionally reflective for at least part of the second type of second device light (wherein the second device light comprises the second type of second device light).

In further embodiments, the light generating system may comprise a third type of second light generating device configured to generate third type of second device light. Especially, the third type of second device light may have a third centroid wavelength in the orange-red wavelength range (i.e. 590-780 nm wavelength range). Furthermore, in embodiments, the optical filter may be transmissive for at least part of the third type of second device light. Hence, in embodiments, the light generating system comprises a third type of second light generating devices configured to generate third type of second device light having a third centroid wavelength in the orange-red wavelength range (wherein the optical filter is transmissive for at least part of the third type of second device light, wherein the second device light comprises the third type of second device light). A combination of the first type of a second device, the second type of a second device and the third type of a second device may provide in embodiments an RGB light source. Further, the addition of one or more of the first type of second device light, the second type of second device light and the third type of second device light to the light generated by the one or more first light generating devices may improve the color gamut of the system light. It will be apparent to the skilled person that additional types of second light generating devices may be configured in the light generating system to further improve the color rendering of system light.

As mentioned above, in embodiments, the one or more first light generating devices (and optionally the one or more second light generating devices) may comprise LED filaments. Yet, in embodiments the third type of light generating devices may comprise LED filaments.

The terms “violet light” or “violet emission” especially relates to light having a wavelength in the range of about 380-440 nm. The terms “blue light” or “blue emission” especially relates to light having a wavelength in the range of about 440-495 nm (including some violet and cyan hues). The terms “green light” or “green emission” especially relate to light having a wavelength in the range of about 495-570 nm. The terms “yellow light” or “yellow emission” especially relate to light having a wavelength in the range of about 570- 590 nm. The terms “orange light” or “orange emission” especially relate to light having a wavelength in the range of about 590-620 nm. The terms “red light” or “red emission” especially relate to light having a wavelength in the range of about 620-780 nm. The term “pink light” or “pink emission” refers to light having a blue and a red component. The term “cyan” may refer to one or more wavelengths selected from the range of about 490-520 nm. The term “amber” may refer to one or more wavelengths selected from the range of about 585-605 nm, such as about 590-600 nm. The phrase “light having one or more wavelengths in a wavelength range” and similar phrases may especially indicate that the indicated light (or radiation) has a spectral power distribution with at least intensity or intensities at these one or more wavelengths in the indicate wavelength range. For instance, a blue emitting solid state light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-495 nm wavelength range.

Here below, some embodiments of the light generating system are described. Embodiments of the light generating system may comprise additional elements that facilitate the operation of the light generating system.

In embodiments, the light generating system may comprise a second light transmissive enclosure. Especially, the second light transmissive enclosure may (at least partly) define a second enclosure volume. Especially, the second enclosure volume may be bounded by a combination of the second light transmissive enclosure and the support. In embodiments, the second enclosure volume may be defined by a second enclosure wall and a second enclosure edge. In embodiments, the second light transmissive enclosure may have a shape resembling a dome. Further, in embodiments, the second light transmissive enclosure may have a bell-like shape, a bulb-like, a cloche-like shape, a hemispherical shape, etc.

In embodiments, the second light transmissive enclosure may especially at least partly enclose the first light transmissive enclosure. Alternatively, in embodiments, the first light transmissive enclosure may at least partly enclose the second light transmissive enclosure. Basically, in embodiments the first enclosure always encloses at least partly the one or more first light generating devices, but may optionally enclose at least partly the one or more second light generating devices. The first light transmissive enclosure may in embodiments thus also be transmissive for at least a part of the second device light.

In embodiments wherein the first enclosure does not (also) at least partly enclose the one or more second light generating devices, optionally a second enclosure may enclose at least partially the one or more second light generating devices and the first enclosure. This may especially be relevant when the one or more second light generating devices comprise LED filaments.

However, as indicated above, in (other) embodiments wherein the first enclosure does not at least partly enclose the one or more second light generating devices, the one or more second light generating devices may be configured to edge-light the edge of the first enclosure.

Yet, in embodiments the second light transmissive enclosure may at least partly enclose the one or more first light generating devices. In further embodiments, the second light transmissive enclosure may (also) at least partly enclose the one or more second light generating devices. Further, the one or more second light generating devices may at least partly be configured external from the first enclosure volume but at least partly within the second enclosure volume. In specific embodiments, the second light transmissive enclosure may at least partly enclose the first light transmissive enclosure, wherein the one or more first light generating devices may be at least partly configured in the first enclosure volume, and wherein the one or more second light generating devices may be at least partly configured external from the first enclosure volume but at least partly within the second enclosure volume.

In embodiments, the second light transmissive enclosure may especially comprise a second light transmissive material. Especially, the second light transmissive material may transmit 90% or higher, such as 95% or higher, especially 99% or higher, more especially 99.5% or higher, including 100% of the first device light and the second device light when perpendicularly incident on the second light transmissive enclosure. Hence, the second light transmissive enclosure may especially be transmissive for incident second device light (and the first device light), and the second device light (and the first device light) may escape via the first light transmissive enclosure. Hence, in embodiments the second light transmissive enclosure may be transparent for the first device light and for the second device light.

In embodiments, the second light transmissive material may comprise the same material as the first light transmissive material. Alternatively, in embodiments, the second light transmissive material may comprise a different material compared to the first light transmissive material.

Further, in embodiments, the second light transmissive enclosure (especially the second enclosure wall) may especially comprise a second upstream face and a second downstream face. The second enclosure edge may especially connect the second downstream face to the second upstream face.

In further embodiments, the second enclosure wall may (also) be configured as a light guide, similarly as described above in relation to the first enclosure (wall).

In yet further embodiments, the second light transmissive enclosure may enclose (one or more of, especially) all of the first light generating devices, the second light generating devices (and optionally the first light transmissive enclosure). Furthermore, in some embodiments, the second light generating enclosure may form a hermetic seal (i.e., especially watertight, more especially airtight) with the support and thus, protect the light generating device from the ingress of dust, dirt, and pollutants. In embodiments the second light transmissive enclosure together with the support may provide a (second) enclosure volume with an IP44 or higher classification. However, other embodiments may thus also be possible.

In further embodiments, the second light transmissive enclosure may comprise scattering particles embedded within the second enclosure wall. Hence, the system light may especially be diffuse light. Additionally or alternatively, in embodiments, the second light transmissive enclosure may comprise light scattering structures (for example scattering dots) configured on or more of the second upstream face and the second downstream face. Hence, the first device light and/or the second device light transmitted via the second light transmissive enclosure (especially via the second enclosure wall) may especially be scattered.

In embodiments, the optical filter may be configured in a plurality of different configurations. As mentioned before, the optical filter may be configured upstream of the first upstream face and/or downstream of the first downstream face. In further embodiments, the second light transmissive enclosure may comprise the optical filter. That is, in embodiments, the optical filter may also be configured upstream of the second upstream face and/or downstream of the second downstream face. Yet further, in embodiments, the optical filter may also be configured as a coating on (at least a part of) the second upstream face and/or the second downstream face.

Note that, while the optical filter (partly) transmissive for the first device light, it may also absorb a part of the first device light. Therefore, to increase the amount of first device light escaping from the light generating system, the optical filter may be configured such that the optical filter (only) partly encloses the one or more first light generating devices. In further embodiments, the optical filter may comprise an optical filter arrangement of a plurality of optical filter parts. Especially, the optical filter parts may be spatially separated by light transmissive parts. In some embodiments, gaps may be present between the one or more optical filter parts (defining intermediate light transmissive parts). In other embodiments, the light transmissive part may comprise light transmissive material configured between the one or more optical filter parts. In embodiments, a part of the first device light may escape via the one or more light transmissive parts and a part of the second device light may be reflected via the one or more optical filter parts (or be absorbed). In specific embodiments, the optical filter may comprise an optical filter arrangement of a plurality of optical filter parts spatially separated by light transmissive parts, wherein the optical filter arrangement is configured such that at least part of the second device light (in the blue-green wavelength range) is reflected at the optical filter parts in a direction away from the one or more first light generating devices, whereas another part of the second device light (in the blue-green wavelength range) is transmitted via the light transmissive parts (without irradiating the one or more first light generating devices).

In embodiments, the second light transmissive enclosure may enclose the first light transmissive enclosure. In such embodiments, the optical filter arrangement may be configured upstream of (and in contact with or not in contact with) the first upstream face or downstream of (and in contact with or not in contact with) the first downstream face (though the optical filter should at least partly be configured between the one or more first light generating devices and the one or more second light generating devices). In (other) embodiments, the first light transmissive enclosure may enclose the second light transmissive enclosure. In such embodiments, the optical filter arrangement may be configured upstream of (and in contact with or not in contact with) the second upstream face or downstream of (and in contact with or not in contact with) the second downstream face (though the optical filter should at least partly be configured between the one or more first light generating devices and the one or more second light generating devices).

In further embodiments, the optical filter may be configured on one or more first parts of the first upstream face, and may not be configured on one or more second parts of the first upstream face. In such embodiments, the optical filter configured on the first parts may (at least partly) absorb the second device light and thus prevent a part of the second device light from being incident on the one or more first light generating devices. Especially, the second device light may be attenuated by the optical filter. Here, attenuation refers to the gradual loss of flux intensity of the second device light as it passes through the optical filter. Hence, in some embodiments, a reduced flux of the second device light may yet reach the first device light. However, in such embodiments, the amount of second device light reaching the one or more first light generating devices may be minimal such as at most 5%, especially at most 2%, more especially at most 1%. Note that in embodiments, the optical filter may also completely prevent the second device light from reaching the one or more first light generating devices. In specific embodiments, the optical filter is configured on one or more first parts of the upstream face, and is not configured on one or more second parts of the upstream face, wherein the one or more first parts and the one or more second parts are configured to prevent at least part of the second device light reaching the one or more first light generating devices. Hence, in this way, the amount of first device light outcoupled by the light generating system may be increased while still (at least partly) preventing irradiation of the first light generating device with the second device light.

Note that, the one or more (light transmissive) second parts may be configured such that a beam of light may enter and exit the first light transmissive enclosure via two second parts without irradiating the first light generating devices. Hence, in some embodiments, the second light generating devices may be configured such that the second device light may enter and exit the first light transmissive enclosure via the second parts (without being incident on the first light generating devices). The first parts may be light absorbing or reflective.

The spectral properties of the system light, especially the CCT and the CRI of the system light may be further controlled by means of additional types of light generating devices. In further embodiments, the light generating system may comprise a plurality of different types of second light generating devices.

The one or more second light generating devices (and the one or more first light generating devices) may comprise solid state light sources. Here, the term “light generating device” may also refer to a plurality of light generating devices which may provide device light having essentially the same spectral power distributions. In (other) specific embodiments, the term “light generating device” may also refer to a plurality of light generating devices which may provide device light having different spectral power distributions. The term “light source” may especially refer to an LED (light emissive diode). In a specific embodiment, the light source comprises a solid state LED light source (such as an LED or laser diode (or “diode laser”)). The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources. Hence, the term LED may also refer to a plurality of LEDs. Further, the term “light source” may in embodiments also refer to a so-called chip-on-board (COB) light source. The term “COB” especially refers to LED chips in the form of a semiconductor chip that is neither encased nor connected but directly mounted onto a substrate, such as a PCB. Hence, a plurality of light emitting semiconductor light source may be configured on the same substrate. In embodiments, a COB is a multi LED chip configured together as a single lighting module.

The term “light source” may also refer to a chip scaled package (CSP). A CSP may comprise a single solid state die with provided thereon a luminescent material comprising layer. The term “light source” may also refer to a midpower package. A midpower package may comprise one or more solid state die(s). The die(s) may be covered by a luminescent material comprising layer. The die dimensions may be equal to or smaller than 2 mm, such as in the range of e.g. 0.2-2 mm. Hence, in embodiments the light source comprises a solid state light source. Further, in specific embodiments, the light source comprises a chip scale packaged LED. Herein, the term “light source” may also especially refer to a small solid state light source, such as having a mini size or micro size. For instance, the light sources may comprise one or more of mini LEDs and micro LEDs. Especially, in embodiment the light sources comprise micro LEDs or “microLEDs” or “pLEDs”. Herein, the term mini size or mini LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm - 1 mm. Herein, the term p size or micro LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm and smaller.

Further, the term “light source” may refer to a semiconductor light-emitting device, such as a light emitting diode (LEDs), a laser diode, a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSELs), an edge emitting laser (EEL), a photonic crystal surface emitting laser (PCSEL), a vertical external cavity surface emitting laser (VECSEL), etc... The term “light source” may also refer to an organic light-emitting diode (OLED), such as a passive-matrix (PMOLED) or an active-matrix (AMOLED). In a specific embodiment, the light source comprises a solid-state light source (such as an LED or laser diode). In an embodiment, the light source comprises an LED (light emitting diode). The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED). The term LED may also refer to a plurality of LEDs. The term “light source” may also relate to a plurality of (essentially identical (or different)) light sources, such as 2- 2000 solid state light sources. In embodiments, the light source may comprise one or more micro-optical elements (array of micro lenses) downstream of a single solid-state light source, such as an LED, or downstream of a plurality of solid-state light sources (i.e. e.g. shared by multiple LEDs). In embodiments, the light source may comprise an LED with on- chip optics. In embodiments, the light source comprises pixelated single LEDs (with or without optics) (offering in embodiments on-chip beam steering).

In specific embodiments, the light source may be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source may comprise an LED.

The phrases “different light sources” or “a plurality of different light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from at least two different bins. Likewise, the phrases “identical light sources” or “a plurality of same light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from the same bin.

The term “solid state light source”, or “solid state material light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, or a superluminescent diode. The term “laser light source” especially refers to a laser. Such laser may especially be configured to generate laser light source light having one or more wavelengths in the UV, visible, or infrared, especially having a wavelength selected from the spectral wavelength range of 200-2000 nm, such as 300-1500 nm. The term “laser” especially refers to a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. Especially, in embodiments the term “laser” may refer to a solid-state laser. In specific embodiments, the terms “laser” or “laser light source”, or similar terms, refer to a laser diode (or diode laser). The term “solid state light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, or a superluminescent diode.

As mentioned above, one or more of the first light generating devices (and/or the one or more second light generating devices) may comprise a luminescent material. The term “luminescent material” may especially refer to a material that can convert first radiation, especially one or more of UV radiation and blue radiation, into second radiation. In general, the first radiation and second radiation have different spectral power distributions. Hence, instead of the term “luminescent material”, also the terms “luminescent converter” or “converter” may be applied. In general, the second radiation has a spectral power distribution at larger wavelengths than the first radiation, which is the case in so-called down-conversion. In specific embodiments, however the second radiation has a spectral power distribution with intensity at smaller wavelengths than the first radiation, which is the case in so-called up- conversion. In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and/or infrared light. For instance, in embodiments the luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. The luminescent material may in specific embodiments also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material emits radiation. In general, the luminescent material will be a down converter, i.e. radiation with a smaller wavelength is converted into radiation with a larger wavelength (Xex<Xem), though in specific embodiments the luminescent material may comprise up-converter luminescent material, i.e. radiation with a larger wavelength is converted into radiation with a smaller wavelength ( x> m). In embodiments, the term “luminescence” may refer to phosphorescence. In embodiments, the term “luminescence” may also refer to fluorescence. Instead of the term “luminescence”, also the term “luminescent material light” or “emission” may be applied. Hence, the terms “first radiation” and “second radiation” may refer to excitation radiation and emission (radiation), respectively. Likewise, the term “luminescent material” may in embodiments refer to phosphorescence and/or fluorescence. The term “luminescent material” may also refer to a plurality of different luminescent materials. Examples of possible luminescent materials are indicated below. Hence, the term “luminescent material” may in specific embodiments also refer to a luminescent material composition. Instead of the term “luminescent material” also the term “phosphor” may be applied. These terms are known to the person skilled in the art.

In embodiments, luminescent materials are selected from garnets and nitrides, especially doped with trivalent cerium or divalent europium, respectively. The term “nitride” may also refer to oxynitride or nitridosilicate, etc. Alternatively or additionally, the luminescent material(s) may be selected from silicates, especially doped with divalent europium.

In specific embodiments, the luminescent material may at least comprise a luminescent material of the type AsBsOn Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc; and wherein the device light may comprise blue device light. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium (Y) or lutetium (Lu) and wherein B comprises at least aluminum (Al). Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B may comprise aluminum (Al); however, in addition to aluminum, B may also partly comprise gallium (Ga) and/or scandium (Sc) and/or indium (In), especially up to about 20% of B, more especially up to about 10 % of B (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and/or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Yi- _xLu_x)3B50i2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1. The term “:Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. For instance, in the case of (Yi-xLux^ALOn Ce, part of Y and/or Lu is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.sgCeo.o sALOn. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

In embodiments, the herein described luminescent material(s) may comprise one or more luminescent materials selected from the group of divalent europium comprising oxynitride type luminescent material, divalent europium comprising nitride type luminescent material, trivalent cerium comprising garnet type luminescent material, and tetravalent manganese comprising hexa-fluoride type luminescent material. Hence, the one or more first LED filaments (and/or the one or more second LED filaments) comprise one or more luminescent materials selected from the group of divalent europium comprising oxynitride type luminescent material, divalent europium comprising nitride type luminescent material, trivalent cerium comprising garnet type luminescent material, and tetravalent manganese comprising hexa-fluoride type luminescent material. Hence,

The term “luminescent material” herein especially relates to inorganic luminescent materials. Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and/or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc..

As mentioned above, the light generating system may comprise a control system configured to control the operation of the first light generating devices (and/or the second light generating devices) in one or more operational modes. In embodiments, the control system may be configured to control a spectral power distribution of the system light. The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and/or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface.

The system, or apparatus, or device may execute an action in a “mode” or “operation mode” or “mode of operation” or “operational mode”. The term “operational mode may also be indicated as “controlling mode”. Likewise, in a method an action or stage, or step may be executed in a “mode” or “operation mode” or “mode of operation” or “operational mode”. This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and/or after executing the mode one or more other modes may be executed. However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode. Would other modes be available, the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible. The operation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability).

Hence, in embodiments, the control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. The term “timer” may refer to a clock and/or a predetermined time scheme. The light generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting. The light generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems.

In yet a further aspect, the invention also provides a lamp or a luminaire comprising the light generating system as defined herein. The luminaire may further comprise a housing, optical elements, louvres, etc. etc... The lamp or luminaire may further comprise a housing enclosing the light generating system. The lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may escape from the housing. In yet a further aspect, the invention also provides a projection device comprising the light generating system as defined herein. Especially, a projection device or “projector” or “image projector” may be an optical device that projects an image (or moving images) onto a surface, such as e.g. a projection screen. The projection device may include one or more light generating systems such as described herein. Hence, in an aspect the invention also provides a lighting device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of elements of the light generating system.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Fig. 1 A-1C schematically depicts cross-sectional views of the light generating system 1000. Fig. 2 schematically depicts another cross-sectional view of the light generating system 1000.

Fig. 3 A-3B depicts the intensity variation and the transmittivity of device light as a function of wavelength.

Fig. 4 schematically depicts an embodiment of the lighting device 1200 comprising the light generating system 1000.

The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 A schematically depicts a cross-sectional view (e.g. perpendicular to the support 700) of an embodiment of the light generating system 1000. In embodiments, the light generating system may comprise one or more first light generating devices 110, one or more second light generating devices 120, a light transmissive enclosure 500, and an optical filter 550. In embodiments, the light generating system 1000 may further comprise a support 700. In embodiments, the light transmissive enclosure 500 may comprise a light transmissive material 505. The light transmissive enclosure 500 may comprise an upstream face 501 and a downstream face 502. In further embodiments, the light transmissive enclosure may comprise a first enclosure edge 508 connecting the upstream face 501 to the second face 502. Especially, the light transmissive enclosure 500 may (at least partly) define an enclosure volume 507. The enclosure volume 507 may especially be defined by the light transmissive enclosure 500 and the support 700. In embodiments, the first light transmissive enclosure 500 may have a shape resembling a dome. Further, in embodiments, the first light transmissive enclosure 500 may have a bell-like shape, a bulb-like, a cloche-like shape, a hemispherical shape, etc (see Fig. 1C, I-V). In further embodiments, the first light transmissive enclosure 500 may (also) have a tubular shape with a flat end on one side (or alternatively a tubular shape with a dome-like shape on one end).

In embodiments, the one or more first light generating devices 110 may at least partly be configured in the enclosure volume 507. In further embodiments, the one or more second light generating devices 120 may (also) be configured in the enclosure volume 507 (see Fig. 1C IV). Yet, as schematically depicted in Fig. 1 A, the one or more second light generating devices 120 may edge light the first enclosure edge 508, see also below.

In embodiments, the one or more first light generating devices 110 may be configured to generate first device light 111 having intensity at one or more wavelengths in the visible wavelength range. Furthermore, the one or more second light generating devices 120 may be configured to generate second device light 121 having intensity at one or more wavelengths in the visible wavelength range. Especially, the second device light 121 may include at least one or more wavelengths in the blue-green wavelength range. In further embodiments, the second device light 121 may comprise one or more wavelengths in the red wavelength range. The second device light may be selected in dependence of the desired color gamut (of the system light). Furthermore, the color temperature of the system light 1001 may be tuned in dependence of the second device light 121 (in combination with the first device light 111).

Further, in embodiments, the light transmissive material 505 may facilitate the propagation of the second device light 121 (and/or the first device light 111) within the light transmissive enclosure 500. Especially, the second device light 121 (and/or the first device light 111) may undergo one or more reflections at either the upstream face 501 and the downstream face 502, and subsequently be outcoupled in a downstream direction.

Further, in the depicted embodiment, the first enclosure edge 508 may be configured in a light-receiving relationship with the second light generating devices 120. In the depicted embodiment, the first enclosure edge 508 is configured in a downstream direction with respect to the second light generating devices 120.

In embodiments, the one or more first light generating devices 110 may comprise one or more first LED filaments 115 (see e.g. also Fig. IB or Fig. 1C). Especially, the first device light 111 may comprise filament light. Furthermore, the one or more second light generating devices 120 may in embodiments comprise one or more solid state light sources.

The optical filter 550 may in embodiments be arranged at least partly enclosing the one or more first light generating devices 110. In the depicted embodiment, the optical filter 550 is arranged upstream of the upstream face 501, such that the optical filter 550 is contact with the upstream face 501. In further embodiments, the optical filter 550 may (also) be applied as a coating on (at least part of) the upstream face 501. Alternatively, in embodiments, the optical filter 550 may be configured at some distance of the upstream face 501 and not in contact with the upstream face 501 (see e.g. also Fig. 1C, III). Note that the directions upstream and downstream may be defined in relation to the first device light 111.

In embodiments, the optical filter 550 may have an analogous shape to the light transmissive enclosure 500 such as a bell-like shape, a bulb-like, a cloche-like shape, a hemispherical shape, etc. Alternatively, the optical filter 550 may have a tubular shape and may be arranged in a tubular configuration, at least partly enclosing the one or more first light generating devices 110 (see Fig. 1C, III and IV).

In embodiments, the optical filter 550 may comprise a dichroic filter. In the embodiment depicted, the optical filter 550 is configured within the enclosure 500. In embodiments, the optical filter 550 (comprising the dichroic filter) may be transmissive for at least part of the first device light 111 and reflective for at least part of the second device light 121. Alternatively, in embodiments, the optical filter 550 may comprise an absorption filter, and may be transmissive for at least part of the first device light 111 and absorptive for at least part of the second device light 121. Especially, the optical filter 550 may be reflective or absorptive for the second device light in the blue-green wavelength range.

In embodiments, the optical filter 550 may (at least partly) be transmissive for the first device light 111. Hence, the first device light 111 generated by the one or more first generating device 110 (at least partly enclosed by the optical filter 550) may be transmitted via the optical filter 550. Furthermore, the one or more second light generating devices 120 may be configured such that at least part of the second device light 121 may be reflected at the optical filter 550 in a direction away from the one or more first light generating devices 110. Alternatively, the second device light 121 incident on the optical filter 550 may be absorbed by the optical filter 550. Hence, the optical filter 550 may facilitate outcoupling the first device light 111 in the downstream direction and prevent (or reduce the amount of) the second device light 121 from travelling upstream of the optical filter 550. Especially, the optical filter 550 may reduce or completely prevent the second device light 121 from being incident on the one or more first light generating devices 110.

Further, in embodiments, the light transmissive enclosure 500 may comprise light outcoupling elements configured to alter the direction of the outcoupled system light 1001. In embodiments, the light outcoupling elements may be configured within the light transmissive material 505, or alternatively on the upstream face and/or the downstream face (of the first light transmissive enclosure 500). In embodiments, the light outcoupling elements may comprise scattering particles 509 embedded in the light transmissive material 505. Hence, the light generating system 1000 may especially outcouple diffuse system light 1001.

In embodiments, the light generating system 1000 may be operated in one or more operational modes. In further embodiments, the light generating system 1000 may comprise a control system 300. The control system 300 may especially control the mode of operation of the light generating system 1000. Especially, the control system 300 may control the spectral power distribution of the system light 1001. In embodiments, in the first operational mode of the light generating system 1000, the system light 1001 may be white light consisting of first device light 111. In further embodiments, the light generating system 1000 may be configured such that in the first operational mode of the light generating system 1000 the system light 1001 may be white light comprising at least part of the first device light 111 and at least part of the second device light 121. Hence, the second device light 121 may in embodiments have a color point more than 10 SDCM from the BBL, or even more than 15 SDCM from the BBL. Further, in embodiments, the light generating system 1000 may be configured to generate in a second operational mode of the light generating system 1001 nonwhite (i.e., colored) system light 1001.

In embodiments, the first light generating devices 110 comprising the first LED filaments 115 may be configured to generate first device light 111 having a correlated color temperature selected from the range of 1500-6500 K. In further embodiments, the light generating system 1000 may comprise at least two different types of first LED filaments 115 configured to generate first device light 111 having correlated color temperatures differing e.g. at least 1000 K. Hence, the light generating system 1000 may be configured to provide in the first operational mode of the light generating system 1000 system light 1001 having a correlated color temperature selected from the range of 1500-6500 K. In further embodiments, the light generating system 1000 may be configured to provide in the first operational mode of the light generating system 1000 system light 1001 having a correlated color temperature selected from the range of T1 - T2, wherein |Tl-T2|>1000K.

Fig. IB schematically depicts a cross-section of the first light generating device 110. Especially, the first light generating device may comprise a first LED filament 115. In embodiments, the second light generating device 120 may (also) comprise a second LED filaments 125 (see Fig. 1C (IV)). The second LED filament 125 may in embodiments be the same type of LED filament as the first LED filament. For brevity, (only) a drawing of the first LED filament is provided, but equally well this may apply to the second LED filament.

The first LED filament 115 may especially comprise a plurality of first light sources 10 configured to generate the first light source light 11. The light sources 10 are configured on an elongated support 750, at one of the main faces 751,752, or only one of these main faces 751,752 (here both faces are provided with the light sources 10). As depicted in the figure, the one or more first light sources 10 may be encapsulated in luminescent material 200. Luminescent material 200 may especially convert at least a part of the incident light (i.e., the first light source light 11) into luminescent material light 201. Note that, a part of the first light source light 11 may be transmitted via the luminescent material 200 without undergoing conversion to luminescent material light 201. The outcoupled first device light 111 may especially comprise the first light source light 11 and the luminescent material light 201. Note that other light (i.e., light other than the first light source light 11) incident on the luminescent material 200 may also undergo conversion to luminescent material light 201. In specific embodiments, the one or more first LED filaments 115 comprise one or more luminescent materials selected from the group of divalent europium comprising oxynitride type luminescent material, divalent europium comprising nitride type luminescent material, trivalent cerium comprising garnet type luminescent material, and tetravalent manganese comprising hexa-fluoride type luminescent material.

Fig. 1C schematically depicts cross-sectional views of embodiments I-V of the light generating system 1000. Especially, a cross-sectional view perpendicular to the support 700 is provided.

The first light transmissive enclosure 500 in embodiment I has a tubular shape (i.e., cylindrical walls) and a dome shaped end. The first light generating devices 110 comprise elongated straight first LED filaments 115. Especially, the first LED filaments 115 may protrude into the first enclosure volume 507. The optical filter 550 is configured on the upstream face 501 of the first light transmissive enclosure 500. Furthermore, the one or more second light generating devices 120 are configured aligned (or in proximity to) the light transmissive window 500, such as below the first light transmissive edge 508. Especially, the first enclosure edge 508 may be configured to receive (more than 95% of) the second device light 121. As mentioned above, the light transmissive enclosure 500 may be configured to guide the incoupled second device light 121 (and/or the incoupled first device light 111) within the light transmissive enclosure 500.

Embodiment II of Fig. 1C schematically depicts another embodiment of the light generating system 1000. In embodiments, the one or more of the first light generating devices 110 further comprise LED filaments 115. Especially, the LED filaments 115 may comprise a coiled shape. Furthermore, the light transmissive enclosure 500 may especially have a bulb-like shape (i.e., a shape resembling an incandescent light bulb). In embodiments, the optical filter 550 may be configured on the upstream face 501 of the first light transmissive enclosure 500 and may also have a bulb-like shape.

Embodiment III schematically depicts another embodiment of the light generating system 1000. In the depicted embodiment, in contrast to embodiments I and II, the optical filter 550 may be configured at a certain predefined distance upstream of the upstream face 501 of the first light transmissive enclosure 500. Furthermore, the optical filter 550 may comprise a tubular shape. In embodiments, the optical filter 550 may be configured at least partly enclosing the one or more first light generating devices 110. Note that the optical filter may form an enclosure 1500 but may also comprise an open end, like a cylindrical shaped optical filter 550.

Embodiment IV depicts a cross-section of the light generating system 1000. In the depicted embodiment, the first light transmissive enclosure 500 has a bulb-like shape. Especially, the first light transmissive enclosure encloses both the first light generating devices 110 and the second light generating devices 120. Furthermore, in the depicted embodiment the optical filter 550 has a tubular shape with a flat (top) end (but other shapes may also be possible). The optical filter 550 may at least partly be configured between the first light generating devices 110 and the second light generating devices 120. In the schematically depicted embodiment, the second light generating devices 120 are configured downstream of the optical filter 550 (such that the optical filter 550 is configured between the first light generating devices 110 and the second light generating devices 120). Furthermore, in embodiments, the one or more second light generating devices 120 further comprise second optical filaments 125.

Embodiment V depicts a light generating system 1000 comprising the first light transmissive enclosure 500 and a second light transmissive enclosure 1500. The second light transmissive enclosure 1500 may define a second enclosure volume 1507. In the depicted embodiment, the second light transmissive enclosure 1500 encloses the first light transmissive enclosure 500. Note that, in embodiments, the second light transmissive enclosure 1500 can enclose the first light transmissive enclosure 500, and in other embodiments, the first light transmissive enclosure 500 encloses the second light transmissive enclosure 1500. In embodiments, the second light transmissive enclosure 1500 may comprise a second light transmissive material 1505. Further, the second the light transmissive enclosure 1500 may comprise a second upstream face 1501 and a second downstream face 1502. In the embodiment depicted, the optical filter 550 is configured on the first upstream face 501.

Further, in the depicted embodiment, the one or more first light generating devices 110 may at least partly be configured in the first enclosure volume 507. Especially, the one or more second light generating devices 120 may at least partly be configured external from the first enclosure volume 507 but at least partly within the second enclosure volume 1507. That is, in embodiments, the one or more second light generating devices 120 may be configured downstream from the first downstream face 502.

Fig. 2 schematically depicts in another cross-sectional view (e.g. in embodiments parallel to a support 700 (not depicted in this Figure)), embodiments I-IV of the light generating system 1000. In embodiment I, the light generating system 1000 only comprises the first light transmissive enclosure 500. The optical filter 550 is configured on the upstream face 501 of the light transmissive window 500. In the depicted embodiment, the first light generating devices 110 further comprises first LED filaments 115. Especially, the optical filter 550 may at least partly enclose the one or more first light generating devices 110. Furthermore, the one or more first light generating devices 110 may be configured upstream of the first upstream face 501 (and the optical filter 550). The one or more second light generating devices 120 may be configured downstream of the optical filter 550. Note that in embodiments, the optical filter 550 may comprise the dichroic filter. The dichroic filter may especially be transmissive for the first device light 111 and reflective for the second device light 121. Hence, the first device light 111 may be transmitted in a downstream direction via the optical filter 550. Additionally, a part of the second device light 121 may be transmitted in the downstream direction. Furthermore, the part of the second device light 121 transmitted in an upstream direction may be reflected by the optical filter 550 in a downstream direction. Alternatively, in embodiments, the optical filter 550 may comprise the absorption filter. The absorption filter may especially be transmissive for the first device light 111 and absorptive for the second device light 121. Hence, preventing the second device light 121 from exciting the first luminescent material.

Embodiment II of Fig. 2 schematically depicts an embodiment of the light generating system 1000 comprising a second light transmissive enclosure 1500 enclosing the first light transmissive enclosure 500. Here, the optical filter 550 is configured on the first upstream face 501 of the first light transmissive enclosure 500. Further, the optical filter 550 is configured enclosing four first light generating devices 100. Especially, the one or more first light generating devices 110 may be configured upstream of the optical filter 550. Additionally, the one or more second light generating devices 120 may be configured downstream of the optical filter 550. In the depicted embodiment, the second light transmissive enclosure 1500 encloses both the first light generating devices 110 and the second light generating devices 120, and the first light transmissive window 500 encloses only the first light generating devices 110. Embodiment III of Fig. 2 schematically depicts yet another embodiment of the light generating system 1000. In the depicted embodiment, the light generating system 1000 may comprise one or more of (i) a first type of second light generating devices 1210 configured to generate first type of second device light 1211 having a first centroid wavelength in the blue wavelength range and (ii) a second type of second light generating devices 1220 configured to generate second type of second device light 1221 having a second centroid wavelength in the green wavelength range. Furthermore, the light generating system 1000 may comprise a third type of second light generating devices 1230 configured to generate third type of second device light 1231 having a third centroid wavelength in the orange-red wavelength range.

Further, in embodiments, the optical filter 550 may be reflective for at least part of the first type light 1211. Especially, the second device light 121 may comprise the first type of second device light 1211. Further, the optical filter 550 may be optionally reflective for at least part of the second type of second device light 1221. Especially, the second device light 121 comprises the second type of second light 1221. Additionally, the optical filter 550 may be transmissive for at least part of the third type of second device light 1231. Especially, the second device light 121 may comprise the third type light 1231.

Further, in the depicted embodiment, the optical filter 550 may comprise an optical filter arrangement of a plurality of optical filter parts spatially separated by light transmissive parts. Especially, the optical filter arrangement may be configured such that at least part of the second device light 121 (in the blue-green wavelength range) may be reflected at the optical filter parts in a direction away from the one or more first light generating devices 110. Whereas, in another part of the light generating system 1000 the second device light 121 (in the blue-green wavelength range) may also be transmitted via two light transmissive parts without irradiating the one or more first light generating devices 110.

In further embodiments, the optical filter 550 may be configured on one or more first parts 5011 of the upstream face 501 and may not be configured on one or more second parts 5012 of the upstream face 501. Especially, the one or more first parts 5011 and the one or more second parts 5012 may be configured to prevent at least part of the second device light 121 reaching the one or more first light generating devices 110.

Embodiment IV schematically depicts yet another embodiment of the light generating system 1000. In the depicted embodiment, the second light transmissive enclosure 1500 is at least partly enclosing the first light transmissive enclosure 500. In the depicted embodiment, the optical filter 550 is configured on one or more first parts 5011 of the first downstream face 502 and may not be configured on one or more second parts 5012 of the first downstream face 1502. In the depicted embodiment, four first light generating devices 110 are configured within the first enclosure volume 507. Herein, first device light 111 may escape via the one or more second parts 5012 and via optical filter 550 configured on one of the first parts 5011. Further, the depicted embodiment comprises four second light generating devices 120 configured within the second enclosure volume 1507. The second light generating devices 120 are configured downstream of the optical filter 550 configured on the one or more first parts 5011. In this embodiment, system light 1001 may comprise: (i) (unfiltered) first device light 111 outcoupled via the second parts 5012, (filtered) device light via the first parts 5011, and (iii) the second device light 121 reflected (by the optical filter 550) at the first parts 5011.

Fig. 3 A-3B depict some aspects. In Fig. 3 A, on the left vertical axis the intensity of the wavelengths of the first device light 111 and (blue) second device light 121 (especially the first type of the second device light 1211) is depicted. As mentioned before, the first device light 111 may especially comprise a combination of (converted) luminescent material light 201 and the first light source light 11. Hence, the first device light 111 (corresponding to the part comprising the first light source light 11) may especially have peak or high intensity in the blue wavelength range (corresponding to the first peak from the left). Additionally, the second peak from the left corresponds to (converted) luminescent light 201 which may have a high intensity for example in the yellow wavelength range. Hence, the first device light 111 comprising a combination of light in the blue wavelength range and the yellow wavelength range may especially be white light. Further, in embodiments, the second device light 121 (especially the first type of second device light 1211) may especially have a peak intensity in the blue wavelength range.

The right vertical axis indicates the transmittivity of the optical filter 550. Lines A and B correspond to the choice of one among two different optical filters 550 that may in embodiments be configured in the light generating system 1000. Optical filter A may have very limited transmittivity for light in the blue wavelength range and may have relatively high transmissivity for the other (higher) wavelength range of light. Optical filter B may have a higher transmissivity for blue light compared to optical filter A. Essentially, both optical filter A and optical filter B may facilitate controlling the amount of blue light outcoupled via the optical filter 550. Note that system light 1001 may comprise a combination of the first device light 111 and the second device light 121. In Fig. 3B, the intensity of the device light as a function of wavelength is provided. In embodiments, the first device light 111 may comprise a combination of the first light source light 11 and the converted luminescent light 201. Especially, in some embodiments, a relatively large amount (more 85%) of the first light source light 11 may undergo conversion to luminescent material light 201. Hence, the first device light 111 comprising a relatively larger amount of luminescent material light 201 compared to first light source light 11 may exhibit a relatively shallow peak (corresponding to the first peak from the left) in the blue wavelength range and a relatively larger peak (corresponding to the second peak from the left) at a higher wavelength range.

The one or more second light generating devices 120 may emit second device light in a plurality of different wavelength ranges. Furthermore, the second device light may further comprise the first type of second light generating devices 1210, the second type of second light generating devices 1220, and a third type of third light generating devices 1230. Especially, the second device light 121 comprising the first type of second device light 1211 may especially have peak intensity in the blue wavelength range. Further, in embodiments, the second device light 121 comprising the second type of second device light 1221 may especially have peak intensity in the green wavelength range. Furthermore, in embodiments, the second device light 121 comprising the third type of second device light 1231 may especially have peak intensity in the orange-red wavelength range.

Fig. 4 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the light generating system 1000. Fig. 4 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000. Hence, Fig. 4 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, or an optical wireless communication device. Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001, and may in specific embodiments thus be system light 1001. Reference 1300 refers to a space, such as a room. Reference 1305 refers to a floor and reference 1310 to a ceiling; reference 1307 refers to a wall. Lighting device 1200 may be a LED filament lamp. In embodiments, it may have a retro shape.

The term “plurality” refers to two or more. The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’. The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species". Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.

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. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system 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. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments of) the method as described herein.

The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

CLAIMS:

1. A light generating system (1000) comprising one or more first light generating devices (110), one or more second light generating devices (120), a first light transmissive enclosure (500), and an optical filter (550), wherein: the first light transmissive enclosure (500) comprises a light transmissive material (505); wherein the first light transmissive enclosure (500) comprises a first upstream face (501) and a first downstream face (502); wherein the first light transmissive enclosure (500) defines a first enclosure volume (507); the one or more first light generating devices (110) are at least partly configured in the first enclosure volume (507); wherein the one or more first light generating devices (110) are configured to generate first device light (111) having intensity at one or more wavelengths in the visible wavelength range; wherein the one or more first light generating devices (110) comprise one or more first LED filaments (115); the one or more second light generating devices (120) comprise one or more solid state light sources; wherein the one or more second light generating devices (120) are configured to generate second device light (121) having intensity at one or more wavelengths in the visible wavelength range, including at least one or more wavelengths in the blue-green wavelength range; the optical filter (550) comprises a dichroic filter; wherein the optical filter (550) is configured within the first light transmissive enclosure (500); wherein the optical filter (550) is transmissive for at least part of the first device light (111) and reflective for at least part of the second device light (121) in the blue-green wavelength range; wherein the one or more second light generating devices (120) are configured such that at least part of the second device light (121) ) in the blue-green wavelength range is reflected at the optical filter (550) in a direction away from the one or more first light generating devices (110); and the light generating system (1000) is configured to generate system light (1001) comprising one or more of (i) at least part of the first device light (111), and (ii) at least part of the second device light (121); and wherein the light generating system (1000) is configured such that in a first operational mode of the light generating system (1000) the system light (1001) is white light having a correlated color temperature in a range from 1500 K to 6500 K.

2. The light generating system (1000) according to claim 1, wherein the optical filter (550) is configured on at least part of the upstream face (501).

3. The light generating system (1000) according to any one of the preceding claims, wherein the one or more first LED filaments (115) are configured to generate first device light (111) having a correlated color temperature selected from the range of 1500- 6500 K; wherein the light generating system (1000) comprises at least two different types of first LED filaments (115) configured to generate first device light (111) having correlated color temperatures differing at least 1000 K.

4. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprise one or more of (i) a first type of second light generating devices (1210) configured to generate first type of second device light (1211) having a first centroid wavelength in the blue wavelength range, wherein the optical filter (550) is reflective for at least part of the first type light (1211), and (ii) a second type of second light generating devices (1220) configured to generate second type of second device light (1221) having a second centroid wavelength in the green wavelength range, wherein the optical filter (550) is optionally reflective for at least part of the second type of second device light (1221).

5. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprise a third type of second light generating devices (1230) configured to generate third type of second device light (1231) having a third centroid wavelength in the orange-red wavelength range.

6. The light generating system (1000) according to any one of the preceding claims 1-5, wherein the light transmissive enclosure (500) comprises a first enclosure edge (508); wherein the first enclosure edge (508) of the first light transmissive enclosure (500) is configured in a light-receiving relationship with the one or more second light generating devices (120); and wherein the first light transmissive enclosure (500) and the one or more second light generating devices (120) are configured such that at least part of the second device light (121) escapes from the first downstream face (502) after multiple reflections within the light transmissive material (505).

7. The light generating system (1000) according to claim 6, further comprising scattering particles (509) embedded in the first light transmissive material (505) and/or surface scattering structures.

8. The light generating system (1000) according to any one of the preceding claims 1-5, wherein the one or more second light generating devices (120) are configured downstream from the first downstream face (502).

9. The light generating system (1000) according to claim 8, wherein one or more second light generating devices (120) comprise second LED filaments.

10. The light generating system (1000) according to any one of the preceding claims 1-9, wherein the first device light (111) has intensity in the blue-green wavelength range; wherein at least one of the one or more first LED filaments (115) and the optical filter (550) are configured such that in the first operational mode of the light generating system (1000) the system light (1001) is white light consisting of first device light (111).

11. The light generating system (1000) according to any one of the preceding claims 1-9, wherein the light generating system (1000) is configured such that in the first operational mode of the light generating system (1000) the system light (1001) is white light comprising at least part of the first device light (111) and at least part of the second device light (121).

12. The light generating system (1000) according to any one of the preceding claims, wherein the optical filter (550) is configured on one or more first parts (5011) of the first upstream face (501), and is not configured on one or more second parts (5012) of the first upstream face (501), wherein the one or more first parts (5011) and the one or more second parts (5012) are configured to prevent at least part of the second device light (121) reaching the one or more first light generating devices (110).

13. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) is configured to generate in a second operational mode of the light generating system (1001) non-white system light (1001).

14. The light generating system (1000) according to any one of the preceding claims, further comprising a control system (300) configured to control a spectral power distribution of the system light (1001).

15. A lighting device (1200) selected from the group of a lamp (1), a luminaire (2), a projector device (3), a disinfection device, a photochemical reactor, an automotive lighting device, and an optical wireless communication device, comprising the light generating system (1000) according to any one of the preceding claims.