Elongated luminaire having a curved section

Abstract

The invention provides a luminaire (1000) comprising an elongated housing (1040) having an elongated light exit window (1050), and a plurality of LED light sources (100) arranged to emit light through the elongated light exit window (1050). The elongated light exit window (1050) comprises a curved section (130) having a central elongation line, CL, extending along a section path length, PL, the curved section (130) being arranged to provide a section light output (140), the curved section (130) having a section shape comprising multiple bends (135) arranged on opposite sides of a section axis SA. The curved section (130) consists of multiple subsections (131), each subsection (131) comprising a subset of the plurality of LED light sources (100). Each subsection (131) of the multiple subsections (131) has a subsection shape with a subsection orientation angle θn and / or a subsection distance Dn to the section axis SA, the subsection orientation angle θn being determined as the angle between the central elongation line CL of the subsection and the section axis SA, the subsection distance Dn being the distance of the central elongation line CL of the subsection measured perpendicular to the section axis SA. Each subsection (131) is arranged to provide a subsection light output (141) having a subsection luminous flux Φn and a subsection angular light distribution. At least one of the subsection luminous flux Φn and the subsection angular light distribution depends on at least one of the subsection orientation angle θn and the subsection distance Dn, so that the section light output varies along the section path length PL.

Description

[0001] ELONGATED LUMINAIRE HAVING A CURVED SECTION

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a luminaire comprising an elongated housing having an elongated light exit window, and a plurality of LED light sources arranged to emit light through the elongated light exit window. The invention further relates to a method for controlling such a luminaire.

[0004] BACKGROUND OF THE INVENTION

[0005] Elongated or long linear LED luminaires are known in the art. For instance, US11371679B1 discloses a linear luminaire including a channel with a bottom and sidewalls that arise from opposite sides of the bottom and a printed circuit board (PCB) including a number of LED light engines mounted in the channel.

[0006] Long linear LED luminaires are often used to illuminate elongated interior spaces, such as hallways, corridors or entrance halls of buildings. To enhance the appearance of such luminaires they may be designed in advanced configurations having irregular shapes. It is desired to improve the aesthetics as well as the optical performance of such elongated luminaires.

[0007] SUMMARY OF THE INVENTION

[0008] Modem luminaires may be configured in irregular shapes. The motivation behind the shape of the luminaire may be dependent on the application of the luminaire. For example, the luminaire may have elongated shapes which may have a decorative effect or which may be routed around furniture, obstacles, or specific locations on the walls and ceilings. Such configurations may have practical advantages in being selective in the location at which light is provided, such as providing more illumination at locations where people move within a space, and less illumination at the walls of the room (in which the luminaire is placed). However, such modem luminaires may extend to significant lengths, spanning entire spaces of multiple meters in length and lighting requirements may vary along the length of the luminaire. Hence, to provide such type of lighting a luminaire of a complimentary geometry having an advanced light output may be used. To this end, a luminaire is provided comprising an elongated housing having an elongated light exit window, and a plurality of LED light sources arranged to emit light through the elongated light exit window. The elongated light exit window comprises a curved section having a central elongation line, CL, extending along a section path length PL, the curved section being arranged to provide a section light output, the curved section having a section shape with multiple bends arranged on opposite sides of a section axis SA. The curved section consists of multiple subsections, each subsection comprising a subset of the plurality of LED light sources, each subsection having a subsection shape with a subsection orientation angle 9nand / or a subsection distance Dnto the section axis SA, the subsection orientation angle On being determined as the angle between the central elongation line CL of the subsection and the section axis SA, the subsection distance Dn being the distance of the central elongation line CL of the subsection measured perpendicular to the section axis SA. Each subsection is arranged to provide a subsection light output having a subsection luminous flux n and a subsection angular light distribution, and at least one of the subsection luminous flux n and the subsection angular light distribution depends on at least one of the subsection orientation angle On and the subsection distance Dn, such that the section light output varies along the section path length PL.

[0009] The above-described luminaire provides a complimentary, free form geometry, suitable for different applications and different spaces. The curved section combines advanced geometry with an adapted light output which is non-constant along the length of the luminaire depending on its geometry. The non-constant, varying light output is configured to cater for different lighting requirements within the space (i.e. configured to provide a desired spatial light distribution in the space).

[0010] The luminaire 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.

[0011] The luminaire comprises a plurality of LED light sources configured within the luminaire. The number of LED light sources comprised by the luminaire and the curved section may vary. The curved section may, in examples, comprise more than 10 LED light sources, more than 50 LED light sources, such as more than 100 LED light sources. The plurality of LED light sources may be configured to generate light. Especially, the light may be light in the visible wavelength range (380-780 nm), such as white light. More especially, the white light may have a correlated color temperature selected from the range of 1800-6500 K and / or a color rendering index of at least 70, such as at least 80. The light may also comprise colored light. However, the plurality of LED light sources may alternatively or additionally be configured to provide light in the infrared wavelength range. This may be useful in embodiments which may be used for local heating or warming purposes. Yet further, the plurality of LED light sources may alternatively or additionally generate light in the ultraviolet wavelength range. This may be useful in embodiments that may be configured to be used for disinfection purposes. The term LED light source may also refer to a plurality of LEDs, such as 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.

[0012] The LED light sources may be configured to generate light having an optical axis, a beam shape, and a spectral power distribution. The term “LED light source” may (thus) refer to a light generating element as such, like e.g. a solid state light source, or e.g. to a package of the light generating element, such as a solid state light source, and one or more of a luminescent material comprising element and (other) optics, like a lens, a collimator. A light converter element (“converter element” or “converter”) may comprise a luminescent material. For instance, a solid state light source as such, like a blue LED, is a LED light source. A combination of a solid state light source (as light generating element) and a light converter element, such as a blue LED and a light converter element, optically coupled to the solid state light source, may also be a LED light source. Hence, a white LED is a LED light source. The luminaire of this invention may similarly operate using OLEDs or laser diodes, for example.

[0013] The plurality of LED light sources may be mounted on a carrier. A carrier may for example be a printed circuit board (PCB) and may be configured to support the plurality of light sources. Hence, the light sources may be physically coupled to the carrier. Further, plurality of light sources may also be electrically connected to the carrier, i.e., the carrier may be configured to provide electricity to the LED light sources. The carrier may have a shape, such as being curved, such as having a shape conform the shape of the curved section. Alternatively, the plurality of LED light sources may be mounted on multiple carriers which may be electrically and / or mechanically connected.

[0014] Each subsection comprises a subset of the plurality of LED light sources, such as at least one LED light source of the plurality of LED light sources. However, a subsection may also comprise more than one LED light source, such as for example more than three LED light sources or more than five LED light sources. A suitable number of subsections may depend on several factors, such as the length of the curved section, the shape of the curved section (e.g. the amount and / or the curvature of the bends). More subsections comprising only one or few LED light sources may allow to better cater to the different lighting requirements within the space.

[0015] The housing of the luminaire comprises an elongated light exit window. The light exit window comprises a curved section. The LED light sources are configured to generate light. The light may escape the luminaire housing via the light exit window. The light exit window may be configured to transmit at least part of the device light (to external of the housing). The light exit window may be configured to refract or redirect (part of) the device light, thus changing an angle or angular light distribution. The elongated light exit window may have properties (e.g. optical or mechanical properties) that vary along the elongation direction. These properties of the elongated light exit window may for example comprise a variable thickness, different (concentrations of) scattering particles, different optical structures that change or vary, or a variable diffusivity, a variable light transmission, or reflectivity. The elongated light exit window may comprise or may be an elongated diffuser, an elongated refractive element, and / or an elongated diffractive element. Different examples and additional details of the light exit window will be described in more detail below.

[0016] The elongated light exit window comprises a curved section having a central elongation line, CL, extending along a section path length PL. Next to the curved section, the luminaire, i.e. the light exit window, may comprise additional sections connecting to the proximal end / or distal end of the curved section. Such additional sections may for example be straight or linear sections. The luminaire, i.e. the light exit window, may also comprise more than one curved section. However, the curved section may also extend to the entire length of the luminaire. The section path length, PL, may in such examples thus be equal to the total length of the luminaire. In examples, the curved section may have a section path length of at least 1 meter, preferably at least 2 meters, more preferably at least 3 meters, most preferably at least 4 meters, such as at least 8 meters. The curved section may have a width, being determined as the width of the light exit window in a direction perpendicular to the section path length. The width of the curved section may be constant along the section path length.

[0017] The central elongation line, CL, extends along the section path length, PL. The section path length extends in the elongation direction of the curved section and thus follows the curved path of the light exit window. The central elongation line, CL, follows the center or centerline of the light exit window along the section path length. The center may be defined as the midpoint defined by a left edge and a right edge of the light exit window. The central elongation line, CL, is thus a curved line.

[0018] The curved section has a section shape with multiple bends arranged on opposite sides of a section axis SA. The multiple bends, curves or turns thus wind around a section axis SA, which may also be described as a central axis or meandering axis. The section axis SA is a straight line extending from the proximate end of the curved section to the distal end of the curved section. The curved section (in particular the multiple bends) intersects, crosses, or contacts the section axis in one or more places. The curved section may have at least 3 bends, at least 5 bends, such as at least 7 bends.

[0019] In other words, the curved section may also be described as having a meandering shape having multiple meander bends winding around a meander axis along a meandering length. The shape of the luminaire may thus be comparable to the meandering shape of a river having a sinuous, or winding, path. The section shape may be characterized by a series of bends or curves that alternate from side to side of the section axis SA.

[0020] The parameters that define the curved or meandering section shape may include the sinuosity index (which is the ratio of the section path length of the curved section PL to the straight-line distance between the section’s proximate and distal ends, thus along the section axis SA), the wavelength (being defined as the distance between two consecutive bends), the amplitude (being the maximum distance of a bend to the section axis), and the degree of curvature or radius of curvature of the bend. Alternatively or additionally, the curved section may also have other shapes, such as a zigzag shape, a sawtooth shape, a sine shape, or an arch shape.

[0021] The curved section consists of multiple subsections such that the multiple subsections together constitute the whole of the curved section. The entire curved section is thus divided into consecutive or contiguous subsections. The subsections may not be physical entities or separate parts of the curved section. The subsections may be understood as different segments of the curved section which may be freely chosen and distributed according to the desired spatial light distribution. To this end, the curved section may consist of at least 5 subsections, such as at least 10 subsections, especially at least 20 subsections. The subsections may have differences in their construction and / or may have differences in the control of the light generated by the subset of the plurality of light sources. The individual subsections may be substantially straight, or the individual subsection may be curved. Different examples are described in more detail below. Each subsection has a subsection shape described by multiple shape parameters of each subsection. These parameters include a subsection orientation angle 0nand / or a subsection distance Dnto the section axis SA.

[0022] The subsection orientation angle 9nof each subsection is determined as the angle between the central elongation line CL of the subsection and the section axis SA. It may thus be described by the subsection deviation angle from the section axis SA, i.e. how the subsection is aligned or positioned with respect to the section axis. Hence, if a subsection is oriented on or in parallel to the section axis, then its subsection orientation angle is 0°. If a subsection is oriented perpendicular to the section axis, then the subsection orientation angle is 90°. A subsection orientation angle 9nof a subsection having a certain length may be defined as its average orientation angle. An average orientation angle may be determined by the central elongation line, CL, passing through the center of the subsection. The center of the subsection may for example be the geometrical center or the center of the subsection light output.

[0023] The subsection distance Dnis the distance of the central elongation line CL of the subsection measured perpendicular to the section axis SA and is measured as a vector perpendicular to the section axis SA. The subsection distance may be understood as the local amplitude, gap, or spacing of the subsection with respect to the section axis. A subsection may have a subsection distance on either side of the section axis SA. Hence, if a subsection is positioned on the section axis, the subsection distance is zero. The subsection distance Dnof a subsection having a certain length may be defined as its average distance from the section axis. An average distance may be determined by the distance of the central elongation line, CL, passing through the center of the subsection. The center of the subsection may for example be determined as the geometrical center or as the center of the subsection light output.

[0024] Each subsection is arranged to provide a subsection light output. The subsection light output is provided by the subset of the plurality of LED light sources of the subsection. The subsection light output depends on the subsection shape such that the section light output is non-constant, i.e. varies along the section path length, PL. Hence, the section light output is a combination of the subsection light outputs of each subsection. The subsection light output of each subsection is preset depending on the subsection shape and may thus vary between different (e.g. neighboring) subsections. A subsection light output which is preset may also be described as predefined, preconfigured, or fixed. Based on the (intended) shape of the curved section the subsection light output may for example be configured during manufacturing or during installation.

[0025] The subsection light output has a subsection luminous flux n and / or a subsection angular light distribution. Next to these properties the subsection light output may also have other lighting properties such as the color or color temperature of the light or the local beam shape.

[0026] The subsection luminous flux n is defined as the luminous flux per subsection, measured in lumen per section. It may also be described as a local luminous flux or a linear flux density, both measured in lumen per meter, which then depends on the length of the subsection. In other words, the subsection luminous flux may be seen as a local brightness of the light emitted by a subsection.

[0027] The subsection angular light distribution may be described as the pattern of light emitted by the subsection in different directions, especially in the plane perpendicular to the central elongation line. This pattern may typically be measured in terms of the intensity of light emitted at different angles (i.e. relative to the central elongation line of the subsection). The subsection angular light distribution may thus be described as the directionality of the light emitted from subsection.

[0028] The subsection luminous flux n may be configured to be varied at least 20%, preferably at least 30%, more preferably at least 40%, most preferably at least 50% along the section path length PL. The subsection luminous flux n measured along the section path length, PL, may have a plurality of N maxima, wherein N is at least 3, preferably at least 4, more preferably at least 5, most preferably at least 6. The subsection luminous flux On may gradually or stepwise change along the section path length PL. The subsection angular light distribution may gradually or stepwise change along the section path length, PL.

[0029] The subsection luminous flux On and the subsection angular light distribution may be substantially constant within a single subsection, but the subsection light output may change with respect to other subsections in the curved section, for example with respect to neighboring subsections. Thereby manufacturability is safeguarded while providing an improved spatial light distribution. Different applications of the above-described luminaire comprising a curved section can be imagined. In some examples it may be desired to illuminate certain objects distributed in a space. However, in other examples, the aesthetics of a curved section may be appreciated, but it may be desired to have functional light in the center of a space, such as in the center of a hallway. In such examples, a homogeneous spatial light distribution in the space may be desired.

[0030] To this end, the section light output may be configured to create a spatial light distribution in a space which is uniform along the section axis, SA.

[0031] The spatial light distribution describes how the section light output is distributed across a surface. It may thus be understood as the pattern of light intensity across a given surface or area, such as the floor of a space. More especially the floor of the space located along the section axis. The spatial light distribution may be influenced by factors such as the distance between the curved section and the surface and the angle of the light.

[0032] The section light output is the combination of each of the subsection light outputs. The section light output may vary along the section path length PL so as to create a spatial light distribution which is uniform along the section axis. To this end, the subsection luminous flux n may depend on the subsection orientation angle 9nand / or the subsection angular light distribution may depend on the subsection distance D from the section axis SA.

[0033] In examples in which the subsection luminous flux n may depend on the subsection orientation angle 0n, a first subsection may have a first subsection orientation angle 91 and a first subsection luminous flux Oi, and a second subsection may have a second subsection orientation angle 92 and a second subsection luminous flux O2. When | 91| > | 92I then Oi < O2, or when | 9 i| < | 92I then Oi > O2.

[0034] Adapting or correcting the subsection luminous flux to the subsection orientation angle as described above contributes to a more homogeneous, constant, or uniform spatial light distribution along the section axis. Such a uniform spatial light distribution may be achieved when the light intensity incident on the surface is constant along the section axis.

[0035] In other words, the larger the subsection orientation angle of a subsection, the lower the subsection luminous flux of said subsection. The smaller the subsection orientation angle of a subsection, the higher the subsection luminous flux of said subsection. Thus, the subsection luminous flux may be corrected for the difference in subsection path length and the subsection’s length when projected on the section axis. In a more specific example, the subsection luminous flux n may be configured to be varied based on the subsection orientation angle On as a function of cos(On).

[0036] Especially, the subsection luminous flux of one subsection may have a maximum when the subsection orientation angle of said subsection is zero. The subsection luminous flux of another subsection may have a minimum when the subsection orientation angle of said subsection is either 90° or -90° (depending on the direction in which the subsection crosses the section axis).

[0037] The subsection luminous flux n may be configured to be varied by one or more of varying a pitch of the plurality of LED light sources, varying a dimming level of the plurality of LED light sources, and varying a light transmission of the curved section of the elongated light exit window.

[0038] The above-described means or properties are effective ways for varying (i.e. correcting, adjusting, modifying) the subsection luminous flux n, either applied separately or in combination. One or more means may be varied per subsection and / or for each subsection.

[0039] In other words, for small subsection orientation angles the subsection luminous flux may be high, thus the subsection may have a small LED pitch, the subset of the plurality of LED light sources may have high brightness or little to no dimming, and / or the light exit window may have a high light transmission. For large subsection orientation angles the subsection luminous flux may be low, thus the subsection may have a large LED pitch, the subset of the plurality of LED light sources may have low brightness or high dimming, and / or the light exit window may have a low(er) light transmission.

[0040] The pitch of the LED light sources can also be referred to as distance or spacing between at least two of the plurality of LED light sources. Thus, as an example, subsection A may have a pitch A and subsection B may have a pitch B.

[0041] The light transmission of the light exit window (i.e. subsections of the curved section) may be varied per subsection. This may be achieved for example by (gradually) varying the height (or thickness) of the light exit window per subsection. Alternatively or additionally, the light exit window may comprise varying concentrations or different types of scattering particles. Especially, the scattering particles may comprise one or more of inorganic particles (e.g. one or more of the following: TiO2 particles, BaSO4 particles, and A12O3 particles) and silicone particles. The scattering particles may provide the advantage of scattering light incident on them hence, providing diffuse lighting. The scattering particles may have dimensions selected from the range of 10-10000 nm, such as 20-4000 nm, especially 100-2000 nm, especially 150-1000 nm.

[0042] The light exit window (i.e. subsections of the curved section) may be configured to transmit most of the light with minimal change to the optical properties of the light. Alternatively, the curved optical window may provide diffuse light via the second main face (especially when the curved optical window comprises scattering particles). Hence, the subsections of the curved section may be transparent or may be translucent.

[0043] Different subsection of the curved section may be configured to transmit at least 30%, at least 50%, such as 70%, such as 85%, such as 90%, especially 95%, more especially 99% of the light emitted by the respective subsets of the plurality of LED light sources. A fraction of the light incident on the light exit window may be reflected, and another fraction of the light incident on light exit window may be transmitted. Further, the transmitted light may undergo scattering within the curved optical window, especially in the presence of scattering particles.

[0044] As described above, the means for varying the subsection luminous flux n may be implemented in the hardware and the construction of the luminaire. However, alternatively or additionally, the subsection luminous flux n may be controlled electronically by varying the dimming level of the subset of the plurality of LED light sources. To this end, the luminaire may additionally comprise a controller, a LED driver, or other electronic circuits, for controlling the dimming level or brightness of the plurality of LED light sources.

[0045] Alternatively or additionally to varying the subsection luminous flux n based on the subsection orientation angle 0n, the subsection angular light distribution may depend on the subsection distance Dnfrom the section axis SA. In such examples, in a plane perpendicular to SA, the subsection angular light distribution may be symmetrical when Dn=0, and the subsection angular light distribution may be asymmetrical when Dn 0, so as to vary a main light emission direction of the subsection light output to emit light in the direction of SA.

[0046] Adapting or correcting the subsection angular light distribution based on the subsection distance D from the section axis SA so as to emit light towards the section axis contributes to a more homogeneous, constant, or uniform spatial light distribution along the section axis. This may be done separately or may be combined with varying the subsection luminous flux n based on the subsection orientation angle 9nfor optimum performance, The subsection angular light distribution may be described as the intensity of light emitted at different angles relative to the central elongation line of the subsection, determined in the plane perpendicular to said central elongation line.

[0047] A subsection angular light distribution which is symmetrical has a main (such as mean or average) light emission direction which is perpendicular to the central elongation line of the light exit window. In examples in which the luminaire is mounted to the ceiling of a space, the main light emission direction is thus nadir or the vertical down direction from the ceiling to the floor of the space.

[0048] A subsection angular light distribution which is asymmetrical has a main light emission direction which deviates from said perpendicular or vertical down direction. Hence, the main light emission direction is not perpendicular to the central elongation line of the light exit window but is tilted or angled towards the section axis.

[0049] The main optical axis (i.e. the main light emission direction) of the subsection angular light distribution may vary at least 20 degrees, preferably at least 30 degrees, more preferably at least 40 degrees, most preferably at least 50 degrees along the section path length.

[0050] A first subsection may have a first subsection distance Di and a first subsection angular light distribution having a first asymmetry ai, being an angle between a nadir and a first main light emission direction, wherein a second subsection may have a second subsection distance D2 and a second subsection angular light distribution having a second asymmetry a2 being an angle between the nadir and a second main light emission direction (110). When DI < D2 then al < a2, or when DI > D2 then al > a2.

[0051] In other words, the larger the subsection distance to the section axis, the larger the asymmetry of the subsection angular light distribution. A subsection having a relatively large distance to the section axis may thus have an angular light distribution with a larger deviation angle from the nadir, thus from the vertical down direction. In examples in which a uniform spatial light distribution is desired, the asymmetry of the angular light distribution (i.e. the main light emission direction) may be directed towards the section axis for all subsections.

[0052] Additionally, an asymmetry an of the angular light distribution may gradually increase with an increasing subsection distance Dn to the section axis SA. The other way around, an asymmetry an of the angular light distribution may gradually decrease with a decreasing subsection distance Dn to the section axis SA. In other words, a difference in the asymmetry of the angular light distribution of each of the individual subsections may be proportional to the difference in subsection distance Dn of each of the individual subsections, especially with respect to neighboring subsections.

[0053] Such a gradually (for example linearly) increasing or decreasing angular light distribution contributes to a pleasant spatial light distribution having an improved homogeneity.

[0054] The subsection angular light distribution may be configured to be varied by one or more of

[0055] (i) varying an angular orientation of the plurality of LED light sources with respect to the elongated light exit window,

[0056] (ii) varying one or more optical features of the curved section of the elongated light exit window.

[0057] The above-described means or properties are effective ways for varying the subsection angular light distribution, either applied separately or in combination. One or more means may be varied per subsection and for each subsection.

[0058] In other words, an asymmetrical angular light distribution may be achieved by either moving the subset of the plurality of light sources with respect to the light exit window, or by varying optical features of the curved section of the elongated light exit window. To this end, the luminaire (i.e. the curved section) may comprise additional optical elements to create asymmetric optics. Such optical elements or facets of such optical elements may be tilted or translated while keeping the subset of the plurality of LED light sources at the symmetric position with respect to the elongated light exit window. The elongated light exit window may comprise a plurality of optical structures arranged along the path length, e.g. wherein the optical structures vary along the path length. The optical features or optical structures may comprise, refractive structures, diffractive structures, light scattering structures and / or light reflective structures. For example, the optical features may differ in length, width, diameter and / or height / thickness.

[0059] The section light output may be configured to create a spatial light distribution in a space which is uniform along the section axis, SA, and a first subsection distance may be larger than 0.5m and a second subsection distance may be larger than -0.5m.

[0060] The total width of the curved section measured perpendicular to the section axis SA may thus be larger than Im while the spatial light distribution created by the curved section may still be uniform along the section axis. The curved section has a section shape which may have at least 4 bends, a first subsection distance may be larger than 0.5m, and the curved section may comprise varying refractive and / or diffractive structures.

[0061] The above-described luminaire may be especially beneficial for luminaires comprising a curved section with 4 or more bends and subsection distances of more than 0.5m in combination with using refractive and / or diffractive structures for varying the subsection angular light distribution.

[0062] The curved section may have a section shape having at least four bends, a first subsection distance Di may be larger than 0.5m, and the curved section may comprises different refractive and / or diffractive structures.

[0063] The section shape may be configured to be modified at one or more positions along the section path length PL.

[0064] The section shape of the luminaire may be determined during the design phase, but that is not always possible or desired when the application or the space in which the luminaire will be installed is yet unknown. Late-stage configuration at the factory or configuration of the luminaire during installation may be desired. To this end, it may be desired to modify the section shape of the curved section to a specific space or application.

[0065] A section shape configured to be modified may be achieved by for example a housing comprising a flexible or bendable material, a housing comprising one or more joints, or a housing comprising elements movable with respect to each other.

[0066] The luminaire may further comprise a controller for dynamically modifying the section light output at one or more positions along the section path length, PL.

[0067] A modifiable section shape may require an modifiable section light output.

[0068] The section light output (i.e. the subsection luminous flux and / or the subsection angular light distribution) may need to be varied to follow the modification made to the section shape to still be able to achieve the desired spatial light distribution. The term “dynamically” in this context needs to be understood as following a modification in the section shape.

[0069] The controller may be one or more of a mechanical controller, an electromechanical controller, and an electronic controller. The section light output may thus be configured to be modified by one or more of mechanical means, electromechanical means, and electronic means.

[0070] Multiple different types of controllers for modifying the section light output may be imagined. The section light output may for example be modified by a mechanical controller using mechanical means, or an electromechanical controller which may include (electro)mechanical sliders, switches, or means for translations or rotations of the plurality of LED light sources, or of optical elements with respect to the plurality of LED light sources. These means may be modified manually or may be modified electromechanically.

[0071] An electronic controller may use electronic control means which may include digital means, lighting control, (remote) control, applications on e.g. a smartphone or tablet, control systems. The electronic means may make use of sensor input or camera input to determine the (modifications in) section shape. Such modifications may be made as late-stage configuration in the factory or manually during installation.

[0072] In a second aspect, a method for controlling the above-described luminaire is provided. The method comprises obtaining shape information indicative of the section shape and the subsection shape of the multiple subsections, obtaining light distribution information indicative of a desired spatial light distribution, determining, based on the shape information and the light distribution information, the subsection luminous flux n and / or the subsection angular light distribution for each of the multiple subsections, and controlling each subsection based on the determined subsection luminous flux n and / or the subsection angular light distribution.

[0073] Shape information may be obtained for example by a user input, by a sensor input or by a camera input. Light distribution information may be obtained from a user input or may be pre-programmed to be a uniform spatial light distribution.

[0074] Based on the obtained shape information and light distribution information, the subsection luminous flux n and / or the subsection angular light distribution is determined for each of the multiple subsections. Each subsection is controlled based on the determined subsection luminous flux n and / or the subsection angular light distribution.

[0075] The control may comprise directly controlling the plurality of LED light sources or electromechanical means for modification of the section light output. It may also comprise giving instructions to a user on modifications necessary to mechanical means to achieve the desired light distribution.

[0076] To this end, the luminaire may comprise a controller or control system which may be configured to control (or operate in a mode of operation), the plurality of LED light sources and / or electromechanical means for modification of the section light output.

[0077] 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.. 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 control system and luminaire 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.

[0078] The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system but may be (temporarily) functionally coupled to the lighting system.

[0079] Hence, in embodiments the control system may (also) be configured to be controlled by an App on a remote device. The lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

[0080] The luminaire 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 luminaire 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.

[0081] However, 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 also refer to a luminaire, which can only operate in a single operation mode (i.e. “on”, without further tunability).

[0082] 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:

[0083] Fig. 1 schematically depicts aspects of a luminaire according to the invention;

[0084] Fig. 2 schematically depicts aspects of the curved section;

[0085] Fig. 3 schematically depicts aspects of a first subsection and a second subsection;

[0086] Figs. 4a-4c schematically depict examples of subsection angular light distributions;

[0087] Figs. 5a-5b show examples of creating asymmetric subsection angular light distributions;

[0088] Fig. 6 schematically depicts an example of a spatial light distribution; and Fig. 7 shows a flow chart of a method to control the luminaire.

[0089] The schematic drawings are not necessarily to scale.

[0090] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0091] Fig. 1 schematically depicts an embodiment of the luminaire 1000 in which the luminaire is suspended from a fastening surface, such as a ceiling in a space. The luminaire 1000 comprises an elongated housing 1040 and a plurality of LED light sources 100. The elongated housing 1040 comprises an elongated light exit window 1050. The plurality of LED light sources 100 are configured to generate light 101 (having a wavelength in the visible wavelength range). The light exit window 1050 is configured to transmit at least part of the light 101 (to external of the housing 1040).

[0092] The luminaire 1000, i.e. the elongated light exit window 1050, comprises a curved section 130. The elongated light exit window 1050 of the curved section 130 is curved. Other elements of the luminaire 1000, i.e. the elongated housing 1040, may be similarly curved so as to follow the section shape of the curved section 130. The elongated housing 1040 may alternatively have a rectangular, oval, or other shape, which may not be curved as the curved section 130. The curved section 130 consists of multiple subsections 131, each subsection 131 comprising a subset of the plurality of LED light sources 100. The curved section 130 is arranged to provide a section light output 140, and each subsection 131 is arranged to provide a subsection light output 141. The subsection light output 141 is generated by the subset of the plurality of LED light sources 100 comprised by the subsection 131. The section light output 140 is thus a combination of the subsection light outputs 141 of each subsection 131.

[0093] Fig. 2 schematically depicts an example and aspects of the curved section 130 as comprised by the luminaire 1000. The curved section 130 has a central elongation line, CL, extending along the section path length, PL. The curved section 130 has a section shape comprising multiple bends 135 arranged on opposite sides of the section axis, SA.

[0094] The section path length, PL, follows the curved path of the light exit window 1050 and the central elongation line, CL, follows the centerline of the light exit window 1050 along the section path length, PL. The section axis, SA, is a straight line extending from the proximate end 138 of the curved section 130 to the distal end 139 of the curved section 130.

[0095] The central elongation line, CL, may thus be longer than the section axis, SA. CL may be at least 1.5 times longer, such as at least 2 times longer, especially at least 3 times longer than SA.

[0096] The curved section has a section shape with multiple bends 135 arranged on opposite sides of the section axis, SA. The section shape may be defined by parameters such as the amplitude A of each bend, the degree of curvature or radius of curvature, r, of the bend.

[0097] The curved section 130 consists of multiple subsections 131 together constituting the curved section 130. Each subsection 131 comprises a subset of the plurality of LED light sources 100. The subsections 131 may each comprise different numbers of LED light sources 100, such as a single LED light source 100, two LED light sources 100, five LED light sources 100, or ten LED light sources. Each subsection 131 may have a different length measured along the section path length, PL. However, the curved section 130 may also comprise subsections 131 which are all of equal length and each comprising the same number of LED light sources 100.

[0098] Fig. 3 depicts aspects of a first subsection 1311 and a second subsection 1312, in particular aspects of the subsection shape and how the subsection light output 141 depends on the subsection shape such that the section light output is non-constant, i.e. varies along the section path length, PL. For illustrative purposes the first subsection 1311 and the second subsection 1312 are not consecutive subsections but have been selected for their different subsection shape parameters. Hence, there may be one or more other subsections 130 located in between the first subsection 1311 and the second subsection 1312, which are not depicted in Fig. 3. The first subsection 1311 has a first subsection shape described by parameters including a first subsection orientation angle 0i and / or a first subsection distance Di to the section axis, SA. The second subsection 1312 has a second subsection shape described by parameters including a second subsection orientation angle 02 and / or a second subsection distance D2 to the section axis, SA.

[0099] The subsection orientation angle 0nof each subsection may be described by how the subsection 131 is aligned or positioned with respect to the section axis, SA. In Fig. 5, the first subsection 1311 is oriented in parallel to the section axis, SA, such that the subsection orientation angle is 0i is 0°. The second subsection 1312 is oriented at an angle 02 to the section axis, SA, which is in this example around 45°.

[0100] The subsection distance Dnis the distance of the central elongation line CL of the subsection measured perpendicular to the section axis SA and is measured as a vector perpendicular to the section axis SA. The first subsection 1311 is located on one side of the section axis and has a first subsection distance Di. The second subsection 1312 is location on the opposite side of the section axis and has a second subsection distance D2. The first subsection angular light distribution depends on DI and the second subsection angular light distribution depends on D2.

[0101] The subsection luminous flux n may depend on the subsection orientation angle 0n. The first subsection 1311 has a first subsection orientation angle 01 and a first subsection luminous flux l, and a second subsection 1312 has a second subsection orientation angle 02 and a second subsection luminous flux 2. 01 is smaller than 02, thus 1 may be larger than 2. The subsection luminous flux of the first subsection 1311 and the second subsection 1312 may be corrected for their difference in length LI, L2 when projected on the section axis, SA.

[0102] Figs. 4a-4c schematically depict examples of subsection angular light distributions, in particular how the subsection angular light distribution depends on the subsection distance D from the section axis, SA.

[0103] Fig. 4b shows an example in which D=0, the subsection 131 thus being essentially located on the section axis, SA. The subsection angular light distribution is symmetrical when D = 0. Hence, the main light emission direction 110 is perpendicular to the light exit window 1050 or parallel to a normal vector of the light exit window 1050. In this example, the main light emission direction 110 is thus in the vertical down direction (i.e. parallel to the nadir 3000) from the ceiling to the floor of the space. Fig. 4a and Fig. 4c show examples in which D 0 and hence the subsection angular light distribution may be asymmetrical and deviate from the nadir 3000 or vertical down direction. The main light emission direction is varied to be tilted or angled towards the section axis SA.

[0104] In Fig. 4a a first subsection 1311 has a first subsection distance Di and a first subsection angular light distribution having a first asymmetry ai, being the angle between the nadir 3000 and the first main light emission direction 110. In Fig. 4c a second subsection 1312 has a second subsection distance D2 and a second subsection angular light distribution having a second asymmetry 012, being the angle between the nadir 3000 and the second main light emission direction 110. Di is larger than D2 and therefore then ai is larger than 012. The first subsection 1311 thus has a first angular light distribution with a larger deviation from the nadir 3000 or vertical down direction. The second subsection 1312 has a second angular light distribution with a smaller deviation from the nadir 3000 or vertical down direction. In this example, a uniform spatial light distribution is desired. Hence, the main light emission direction is directed towards the section axis, SA, for all subsections.

[0105] Figs. 5a-5b show two examples of how subsection angular light distributions may be created which have an asymmetry. The asymmetry of the subsection angular light distribution may be varied by one or more of varying an angular orientation of the plurality of LED light sources 100 with respect to the elongated light exit window 1050 and varying one or more optical features of the curved section 130 of the elongated light exit window 1050.

[0106] Fig. 5a shows a first subsection 1311 having a first angular light distribution having a first asymmetry. The asymmetry may be varied per subsection 131 by varying optical elements (i.e. optical features or optical structures) 1055 of the elongated light exit window 1050. Such optical elements 1055 or facets of such optical elements 1055 may be tilted or translated while keeping the subset of the plurality of LED light sources 100 at the symmetric position (which may be the central elongation line CL) the with respect to the elongated light exit window 1050. Optical elements 1055 may include e.g. diffusing structures, refractive structures, or diffractive structures.

[0107] Fig. 5b shows a second subsection 1312 having a second angular light distribution having a second asymmetry. The second asymmetry is in this example equal to the first asymmetry. It is however achieved by different means, being by moving (translating and / or rotating) the subset of the plurality of LED light sources 100 to vary an angular orientation with respect to the light exit window 1050. Fig. 6 schematically depicts an example of a luminaire 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system comprised by or functionally coupled to the luminaire 1000. In examples, the curved section 130 may be configured provide a section light output 140 creating a spatial light distribution 2100 on one or more surfaces in a space 2000. Especially, the curved section 130 may illuminate the walls, or the floor, or the ceiling, in a space 2000. The section light output 140 may be corrected based on the section shape so as to create a spatial light distribution 2100 in a space 2000 which is uniform along the section axis, SA.

[0108] Fig. 7 schematically shows a method for controlling the above-described luminaire comprising a curved section, the method comprising: obtaining shape information S10 indicative of the section shape and the subsection shape of the multiple subsections, obtaining light distribution information S20 indicative of a desired spatial light distribution, determining S30, based on the shape information and the light distribution information, the subsection luminous flux n and / or the subsection angular light distribution for each of the multiple subsections, controlling S40 each subsection based on the determined subsection luminous flux n and / or the subsection angular light distribution.

[0109] 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.

[0110] 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.

[0111] Aspects of the invention may be implemented in a computer program product, which may be a collection of computer program instructions stored on a computer readable storage device which may be executed by a computer. The instructions of the present invention may be in any interpretable or executable code mechanism, including but not limited to scripts, interpretable programs, dynamic link libraries (DLLs) or Java classes. The instructions can be provided as complete executable programs, partial executable programs, as modifications to existing programs (e.g. updates) or extensions for existing programs (e.g. plugins). Moreover, parts of the processing of the present invention may be distributed over multiple computers or processors or even the ‘cloud’.

[0112] The term “plurality” refers to two or more.

[0113] 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%.

[0114] The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’.

[0115] 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".

[0116] 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.

[0117] 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.

[0118] 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”.

[0119] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0120] 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.

Claims

CLAIMS:

1. A luminaire (1000) comprising an elongated housing (1040) having an elongated light exit window (1050), and a plurality of LED light sources (100) arranged to emit light (101) through the elongated light exit window (1050), wherein the elongated light exit window (1050) comprises a curved section (130) having a central elongation line, CL, extending along a section path length, PL, the curved section (130) being arranged to provide a section light output (140), the curved section (130) having a section shape comprising multiple bends (135) arranged on opposite sides of a section axis SA, wherein the curved section (130) consists of multiple subsections (131), each subsection (131) comprising a subset of the plurality of LED light sources (100), wherein each subsection (131) of the multiple subsections (131) has a subsection shape having a subsection distance Dn to the section axis SA, the subsection distance Dn being the distance of the central elongation line CL measured perpendicular to the section axis SA, wherein each subsection (131) is arranged to provide a preset subsection light output (141) having a preset subsection angular light distribution, wherein each subsection angular light distribution is configured depending on the respective subsection distance Dn such that, in a plane perpendicular to the section axis SA:(i) the subsection angular light distribution is symmetrical when Dn=0, and(ii) the subsection angular light distribution is asymmetrical having a main light emission direction oriented towards the section axis SA when Dn 0.

2. The luminaire (1000) according to claim 1, wherein a first subsection (1311) has a first subsection distance Di and a first subsection angular light distribution having a first asymmetry ai, the first asymmetry ai being an angle between a nadir (3000) and a first main light emission direction (110), wherein a second subsection (1312) has a second subsection distance D2 and a second subsection angular light distribution having a second asymmetry 012,the second asymmetry a? being an angle between the nadir (3000) and a second main light emission direction (110), and wherein(i) when Di < D2 then ai < 012, or(ii) when Di > D2 then ai > 012.

3. The luminaire (1000) according to claim 2, wherein the asymmetry an of the angular light distribution gradually increases with an increasing subsection distance Dn of a subsection (131) to the section axis SA and wherein the main light emission direction of the subsection angular light distribution is configured to vary at least 30 degrees along the section path length.

4. The luminaire (1000) according to any one of the preceding claims, wherein the subsection angular light distribution of each subsection is configured to be set by one or more of(i) an angular orientation of the plurality of LED light sources (100) with respect to the elongated light exit window (1050) of each subsection,(ii) one or more optical features of the curved section (130) of the elongated light exit window (1050) of each subsection.

5. The luminaire (1000) according to any one of the preceding claims, wherein the subsection shape further comprises a subsection orientation angle On, the subsection orientation angle On being determined as the angle between the central elongation line CL of the subsection and the section axis SA, wherein the subsection light output (141) further has a preset subsection luminous flux n, and wherein each subsection luminous flux n is configured depending on the respective subsection orientation angle On.

6. The luminaire (1000) according to claim 5, wherein a first subsection (1311) has a first subsection orientation angle 01 and a first subsection luminous flux Ol, wherein a second subsection (1312) has a second subsection orientation angle 02 and a second subsection luminous flux 2, and wherein(i) when | 0 i| > | 02I then i < 2, or(ii) when | 0 i| < | 02I then i > 2.

7. The luminaire (1000) according to any one of claims 5-6, wherein the subsection luminous flux n is configured to be set based on the subsection orientation angle On as a function of cos(On).

8. The luminaire (1000) according to any one claims 5-7, wherein the subsection luminous flux n of each subsection is configured to be set by one or more of(i) a pitch of the plurality of LED light sources (100) of each subsection,(ii) a dimming level of the plurality of LED light sources (100) of each subsection,(iii) a light transmission of the curved section (130) of the elongated light exit window (1050) of each subsection.

9. The luminaire (1000) according to any one of the preceding claims, wherein the section light output (140) is configured to create a spatial light distribution (2100) in a space (2000), wherein the spatial light distribution (2100) is uniform along the section axis, SA, and wherein a first subsection distance is larger than 0.5m and a second subsection distance is larger than -0.5m.

10. The luminaire (1000) according to any one of the previous claims, wherein the curved section (130) has a section shape having at least four bends, wherein a first subsection distance Di is larger than 0.5m, and wherein the curved section (130) comprises different refractive and / or diffractive structures.

11. The luminaire (1000) according to any one of the preceding claims, wherein the curved section (130) has a section path length of at least 1 meter, and wherein the curved section (130) consists of at least 5 subsections (131).

12. The luminaire (1000) according to any one of the preceding claims, wherein the section shape is configured to be modified at one or more positions along the section path length, PL.

13. The luminaire (1000) according to claim 12, further comprising a controller configured to modify the section light output (140) at one or more positions along the section path length, PL, based on the modified section shape.

14. The luminaire (1000) according to claim 13, wherein the controller is one or more of a mechanical controller, an electromechanical controller, and an electronic controller.

15. A method for controlling the luminaire according to any one of claims 12-14, comprising: obtaining shape information (S10) indicative of the section shape and the subsection shape of the multiple subsections, obtaining light distribution information (S20) indicative of a desired spatial light distribution, determining (S30), based on the shape information and the light distribution information, the subsection angular light distribution for each of the multiple subsections, and controlling (S40) each subsection based on the determined subsection angular light distribution.

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