Light generating system with foldable reflector

Abstract

The invention provides a light generating system (1000) comprising a foldable reflector (200) and a plurality of light generating devices (100), wherein the foldable reflector (200) has (a) a first side (210) comprising first folding elements (215) and (b) a second side (220) comprising second folding elements (225), wherein at least part of the light generating devices (100) are arranged at the first side (210) and are configured to provide device light (101), wherein the first side (210) is reflective for the device light (101), and wherein the first folding elements (215) and the second folding elements (225) are configured to allow folding of the foldable reflector (200), wherein the foldable reflector (200) is switchable between an unfolded configuration (201) and a folded configuration (202), wherein: in the unfolded configuration (201) the foldable reflector (200) has a planar shape; and in the folded configuration (202) the foldable reflector (200) has a 3D shape comprising a repeating structure of parallelogram segments (400), wherein along a first axis (Al) the 3D shape comprises alternating valleys (266) and peak ranges (267) at the first side (210), wherein the valleys (266) and peak ranges (267) extend along a second axis (A2) perpendicular to the first axis (Al), and wherein the valleys (266) and the peak ranges (267) have zigzag shapes.

Description

[0001] Light generating system with foldable reflector

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a light generating system comprising a foldable reflector and a plurality of light generating devices. The invention further relates to a lighting device comprising the light generating system.

[0004] BACKGROUND OF THE INVENTION

[0005] Bendable electronic devices are known in the art. For instance, JP2017220555 A describes an electronic device which can be bent, deformed, and expanded, a plurality of flat plate parts, a bendable hinge part which connects the plurality of flat plate parts, a gap that is provided at an intersection point of both hinge parts, and a neutral surface of the hinge part.

[0006] SUMMARY OF THE INVENTION

[0007] Light generating systems with foldable luminaires may have several advantages over non-foldable luminaires. For instance, a foldable luminaire can be transported in a space-efficient unfolded (e.g., flat) state, yet may provide a suitable 3D structure during use. Further, foldable luminaires may facilitate size adjustments, e.g., to adjust an emitting area to a required size. This may, for instance, be convenient in view of regional deviations in ceiling grid size. Yet further, foldable luminaires may facilitate adjusting a beam shape. A beam width may, for example, be adjusted to a luminaire spacing to balance discomfort glare (UGR score may become worse for wider beams) and illuminance uniformity in a space (illuminance uniformity may improve for wider beams).

[0008] Although foldable diffuse reflector / diffuser optics may be known in the art and may have benefits for transport and late-stage customizable installation, existing solutions may mainly be decorative and unsuitable for professional indoor lighting. For instance, prior art foldable optics may not satisfy the requirements of European workplace standard EN 12464-1.

[0009] 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.

[0010] According to a first aspect, the invention provides a light generating system comprising a foldable reflector and a plurality of light generating devices. The foldable reflector may have (a) a first side comprising first folding elements, such as first grooves, and (b) a second side comprising second folding elements, such as second grooves, wherein the first folding elements and the second folding elements are configured to allow folding of the foldable reflector (at the folding elements). The light generating devices may be configured to provide device light. In embodiments, the foldable reflector may be reflective for the device light, especially at least the first side of the foldable reflector may be reflective for the device light. Further, in embodiments, (at least part of) the light generating devices may be arranged at the first side. The foldable reflector may be switchable (or ‘foldable’) between a folded configuration (or “folded state”) and a (fully) unfolded configuration (or “unfolded state”), especially by (un)folding at the first folding elements and at the second folding elements. In the unfolded configuration, the foldable reflector may have a planar shape, i.e., the foldable reflector may be essentially flat. In the folded configuration, the foldable reflector may have a 3D shape comprising a repeating structure of parallelogram segments. Especially, along a first axis Al the 3D shape may comprise alternating valleys and peak ranges (or “mountain ranges”) at the first side. The valleys and peak ranges may extend along a second axis A2 perpendicular to the first axis Al. In embodiments, the repeating structure may repeat along the first axis Al and along the second axis A2. In further embodiments, the valleys and the peak ranges have zigzag shapes.

[0011] In specific embodiments, the light generating system may comprise a foldable reflector and a plurality of light generating devices, wherein the foldable reflector has (a) a first side comprising first folding elements and (b) a second side comprising second folding elements, wherein the first folding elements and the second folding elements are configured to allow folding of the foldable reflector, wherein the light generating devices are configured to provide device light, wherein the first side is reflective for the device light, and wherein the light generating devices are arranged at the first side, wherein the foldable reflector is switchable between a folded configuration and an unfolded configuration, wherein: in the unfolded configuration the foldable reflector has a planar shape; and in the folded configuration the foldable reflector has a 3D shape comprising a repeating structure of parallelogram segments, wherein along a first axis Al the 3D shape comprises alternating valleys and peak ranges at the first side, wherein the valleys and peak ranges extend along a second axis A2 perpendicular to the first axis Al, and wherein the valleys and the peak ranges have zigzag shapes.

[0012] With such a light generating system, above-mentioned benefits of a foldable luminaire may be obtained while simultaneously providing an appropriate beam shape for general indoor lighting, e.g., according to EN12464-1 : low glare (UGR<19) for high flux densities and an adjustable FWHM beam width between 2x40 deg and 2x60 deg to provide a high degree of illuminance uniformity. In particular, with a symmetric positioning of light generating devices, a quadrant symmetric beam close to a square symmetry may be provided. The foldable reflector may be particularly suitable for use in combination with a deformable chain of LED filaments, which may provide a smooth beam shape, may allow for simultaneous size / shape adjustment of both light source and reflector optics, and may provide a beam having a beam shape approximating a rotational symmetry. Alternatively, LEDs on a flexible substrate may be used.

[0013] Embodiments with foldable specular reflectors (e.g. ESR foil) may provide narrow beams, which may be particularly suitable for downlighters.

[0014] Hence, the invention may provide a light generating system comprising a foldable reflector and a plurality of light generating devices.

[0015] The foldable reflector may be reversibly foldable, especially between a (fully) folded configuration and a (fully) unfolded configuration, optionally with one or more intermediate folding states in between. In the (fully) unfolded configuration, the foldable reflector may have a planar shape, i.e., the foldable reflector may be substantially elongated in two dimensions relative to a third dimension, especially elongated along the first and second axis relative to along a third axis (see below). In particular, in the unfolded configuration (or “unfolded state”), a thickness of the foldable reflector may be substantially smaller than a length and a width of the foldable reflector.

[0016] The foldable reflector, especially a first side of the foldable reflector, may be configured to reflect light provided by the light generating devices, i.e., the light generating devices may be configured to provide device light, wherein the foldable reflector, especially the first side of the foldable reflector, is configured to reflect (at least part ol) the device light incident on the (first side of the) foldable reflector.

[0017] In embodiments, the foldable reflector may have a first side and a second side. The first side and the second side may especially be opposite sides along a third axis, i.e. opposite across the thickness of the foldable reflector. The third axis may be perpendicular to the first axis Al and to the second axis A2. In embodiments, (at least) the first side of the foldable reflector may be reflective for the device light. In further embodiments, the first side may be configured to reflect at least 60%, such as at least 70%, especially at least 80%, such as at least 90%, more especially at least 95% of the device light received by the first side of the foldable reflector. In further embodiments, the first side of the foldable reflector may be configured to reflect at least 98%, such as at least 99%, including 100%, of the device light received by the first side of the foldable reflector.

[0018] In further embodiments, (at least) the second side of the foldable reflector may be reflective for the device light. In further embodiments, the second side may be configured to reflect at least 60%, such as at least 70%, especially at least 80%, such as at least 90%, more especially at least 95% of the device light received by the second side of the foldable reflector. In further embodiments, the second side of the foldable reflector may be configured to reflect at least 98%, such as at least 99%, including 100%, of the device light received by the second side of the foldable reflector.

[0019] Hence, in embodiments, both the first side and the second side of the foldable reflector may be reflective. Such embodiments may provide additional flexibility in selecting the optical properties of the light generating system. For instance, if the foldable reflector has different reflective properties on different sides, the beam shaping possibilities of the foldable reflector are extended. For instance, one side can be white reflective (e.g., using via paint, paper, or plastic) and the other side may be specularly (e.g., using aluminum, silver coating, or an ESR foil). The beam can then be adjusted by placing the light generating devices on the other side and turning around the reflector, or by having light generating devices on both sides and switching on only one side. Hence, in embodiments, the first side and the second side may have different reflective properties for the device light.

[0020] In further embodiments, the first side and the second side may have (essentially) the same reflective properties for the device light. Such embodiments may also provide additional flexibility in selecting optical properties in comparison with embodiments having a single reflective side. For instance, in such embodiments, the light generating devices may be arranged differently on the first side and on the second side, which positioning may affect the beam shapes. In particular, a light generating device arranged in a valley proximate to a valley floor (or “valley bottom”) may produce a more narrow beam than a light generating device arranged remotely from the valley floor.

[0021] Hence, in embodiments, the light generating system may comprise light generating devices. The light generating devices may be configured to provide device light. Especially, the light generating devices may be configured to provide (at least part ol) the device light to the foldable reflector.

[0022] In embodiments, (at least part ol) the light generating devices may be arranged at the first side of the foldable reflector. Especially, the light generating devices (arranged at the first side) may be configured to provide (at least part of) the device light to the first side of the foldable reflector. Hence, the light generating devices may provide device light to the first side of the foldable reflector and the foldable reflector may be configured to reflect (at least part of) the device light incident on the first side.

[0023] In further embodiments, a second group of the light generating devices may be arranged at the second side of the foldable reflector. Especially, the light generating devices of the second group may be configured to provide (at least part of) (second) device light to the second side of the foldable reflector. Hence, the light generating devices (of the second group) may be configured to provide (second) device light to the second side of the foldable reflector. In such embodiments, the foldable reflector may be configured to reflect (at least part of) the device light incident on the second side.

[0024] The foldable reflector may comprise folding elements facilitating the folding of the foldable reflector.

[0025] In particular, in embodiments, the first side may comprise first folding elements. The first folding element may be configured to allow folding of the foldable reflector (at the first folding elements). In particular, the first folding elements may - relative to a (fully) unfolded configuration - be configured to allow folds bringing surfaces on the first side closer together.

[0026] Similarly, in embodiments, the second side may comprise second folding elements. The second folding element may be configured to allow folding of the foldable reflector (at the second folding elements). In particular, the second folding elements may - relative to a (fully) unfolded configuration - be configured to allow folds bringing surfaces on the second side closer together.

[0027] The first folding elements and the second folding elements may, for instance, comprise grooves and / or hinges, especially grooves, or especially hinges. The first folding elements and the second folding elements may especially comprise the same type of folding elements, e.g., both the first folding elements and the second folding elements may comprise grooves, or both the first folding elements and the second folding elements may comprise hinges. In further embodiments, the folding elements may comprise fold lines, especially fold lines formed by (pre-)folding of the foldable reflector.

[0028] In embodiments, the first folding elements and the second folding elements may be configured to allow folding of the foldable reflector, especially between a (fully) folded configuration and a (fully) unfolded configuration. Hence, the foldable reflector may be switchable between (or “foldable between”) a folded configuration and an unfolded configuration, especially by folding at the first folding elements and at the second folding elements.

[0029] In embodiments, the first folding elements and the second folding elements may (both) be hinges.

[0030] In further embodiments, the first folding elements and the second folding elements may (both) be grooves. Especially, the first folding elements and the second folding elements may have groove shapes selected from the group comprising V-shapes (or ‘V- shapes’), U-shapes and rectangular shapes, especially V-shapes. The first folding elements defining the first line segments and the second folding elements defining the second line segments may especially have a (same) segment groove depth ds. Especially, the foldable reflector may have a thickness D in the unfolded configuration, wherein ds / D is selected from the range of 0.05 - 0.99, especially from the range of 0.4 - 0.98, such as from the range of 0.6-0.95. In further embodiments, ds / D is selected from the range of 0.05 - 0.95, such as from the range of 0.1 - 0.9, especially from the range of 0.2 - 0.8.

[0031] In further embodiments, the first folding elements defining the first zigzag lines and the second folding elements defining the second zigzag may have a (same) zigzag groove depth dz. In such embodiments, the foldable reflector may have a thickness D in the unfolded configuration, wherein dz / D is selected from the range of 0.4 - 0.98, such as from the range of 0.6-0.95.

[0032] Especially, in further embodiments, dz:dsmay be selected from the range of 0.5 - 2.0, such as from the range of 0.75 - 1.5, especially from the range of 0.9 - El. In further embodiments, dz and ds may be (about) the same.

[0033] As mentioned above, in the unfolded configuration the foldable reflector may have a planar shape. In particular, in the unfolded configuration, the foldable reflector may define a plane (or “have a planar shape parallel to a plane”). The plane may herein also be referred to as an ‘unfolded reflector plane’. The first folding elements and the second folding elements may especially be configured to allow folding (at the folding elements) between adjacent parallelogram segments (of the parallelogram segments) to provide an angle between the parallelogram segments and the plane. In particular, in the folded configuration (or “folded state”), the parallelogram segments may be arranged at (about) a smallest angle 0 to the plane, i.e., each parallelogram segment may define a parallelogram plane arranged at (about) a smallest angle 0 to the plane. In embodiments, the smallest angle 0 may be (independently) selected from the range of 45° - 75°, such as from the range of 50° - 70°, especially from the range of 55° - 65°. In particular, for small folding angles, e.g., smaller than 4°, there may be too much light at large angles with respect to the vertical and the UGR may be too high (the luminaire may be glary). In contrast, for large folding angles, e.g., angles above 75°, the beam may be relatively narrow, i.e., many luminaires may be needed to create a uniform illumination of the space, which may be not economical. Furthermore, the optical efficiency of a reflector with a high folding angle may be rather low (most light needs multiple reflections to escape in that case). Smallest folding 0 in the range of 55° - 65° may provide particularly suitable lighting properties. In further embodiments, the parallelogram segments may vary at most 10% in the smallest angle 0, such as at most 5%, especially at most 2%, including 0%.

[0034] Hence, in the unfolded configuration the foldable reflector may define a plane, wherein the first folding elements and the second folding elements are configured to allow folding between adjacent parallelogram segments such that in the folded configuration the parallelogram segments are arranged at a smallest angle 0 to the plane, wherein 0 is (independently) selected from the range of 50° - 70°, especially from the range of 55° - 65°.

[0035] The phrase “A may be arranged at a smallest angle 0 to B” and similar phrases herein indicate that 0 is the smallest angle between A and B. For instance, two planes may make angles of 45° and 135° relative to one another, and 0 may correspond to the 45° angle.

[0036] In embodiments, the smallest angle 0 may especially be (essentially) the same angle for the majority of the parallelogram segments. In particular, in further embodiments, for at least 70% of (a total number ol) the parallelograms segments may apply that in the folded configuration the parallelogram segment is arranged at the smallest angle 0 with the plane, such as for at least 80%, especially for at least 90%, such as for at least 95%, including 100%.

[0037] In further embodiments, in the folded configuration, the parallelogram segments may vary in their smallest angle 0 to the plane. Especially, each parallelogram segment may have a smallest angle 0 to the plane independently selected from the range of 45° - 75°, such as from the range of 50° - 70°, especially from the range of 55° - 65°. In both the folded and in the unfolded configurations the parallelogram segments may be (essentially) flat (or “planar”), i.e., the individual parallelogram segments may be essentially unbent. In particular, the foldable reflector may be folded at the first and second folding elements without providing a substantial force on the parallelogram segments.

[0038] In specific embodiments, in the folded configuration applies that: each parallelogram segment is flat; and at least 95% of the parallelograms segments are arranged at the (same) smallest angle 0 with the plane, especially wherein the smallest angle 0 is selected from the range of 45° - 75°, such as from the range of 50° - 70°, especially from the range of 55° - 65°.

[0039] In such embodiments, in the unfolded configuration the first folding elements and the second folding elements may especially be V-shaped grooves having internal angles 0v, especially wherein 0v is (approximately) 2*0. In embodiments, 0vmay be (independently) selected from the range of 90° - 150°, such as from the range of 100° - 140°, especially from the range of 110° - 130°.

[0040] In further embodiments, the foldable reflector may be collapsable. In particular, in embodiments, the foldable reflector may be switchable between the unfolded configuration and a fully collapsed configuration, especially via the folded configuration. In the fully collapsed configuration the foldable reflector may have a 3D shape comprising a repeating structure of parallelogram segments, wherein surfaces of adjacent parallelogram segments (400) abut each other.

[0041] In the folded configuration, the foldable reflector may have a 3D shape comprising a repeating structure of parallelogram segments. In particular, the foldable reflector may have a 3D shape defined by a plurality of parallelogram segments. Hence, the first folding elements and the second folding elements may be configured to facilitate folding of the foldable reflector to provide a plurality of parallelogram segments.

[0042] The term “parallelogram” may herein refer to a four-sided rectilinear figure with parallel opposing sides.

[0043] The parallelogram segments may have a segment thickness (essentially) equal to the thickness of the thickness of the foldable reflector in the (fully) unfolded configuration (along the third axis A3). Further, the parallelogram segments may be essentially flat. In particular, the foldable reflector may be bent between the parallelogram segments, while the parallelogram segments are (essentially) unstrained.

[0044] As mentioned above, the 3D shape may have a repeating pattern. In particular, at the first side and along a first axis Ai the 3D shape may comprise alternating valleys and peak ranges (or “mountain ranges”). The valley and peak ranges may essentially correspond to “valley folds” and “mountain folds”, i.e., as seen from the first side the peak ranges may be pointing out of the foldable reflector whereas the valleys may be receded into the foldable reflector. It will be clear to the person skilled in the art that the valleys of the first side may correspond to peak ranges at the second side and, analogously, that the peak ranges of the first side may correspond to valleys at the second side.

[0045] In embodiments, the valleys and peak ranges may extend along a second axis A2, wherein the second axis A2 is perpendicular to the first axis Ai. In particular, the valleys and the peak ranges may have zigzag shapes, wherein the zigzag shapes extend along the second axis. The term “zigzag shape” may herein refer to a line comprising alternating opposing turn comers, especially wherein each turn has the same turn internal angle, e.g., alternating -40° and 40° turn comers. In particular, after two turn comers the net turn angle may be (essentially) 0°. The turn comers may especially be “sharp” (or “abrupt”) as opposed to smooth bends. For instance, a zigzag shape may approximate the following pattern:

[0046] In embodiments, in the unfolded configuration, the first folding elements and the second folding elements may together define a folding element pattern. In particular, in the unfolded configuration, the first folding elements and the second folding elements may together define the folding element pattern in a superposition of the first side and the second side, i.e., a superposition along the third axis A3.

[0047] The folding pattern may especially indicate the fold lines, including the side on which the fold lines are located. The folding element pattern may especially comprise a plurality of parallelly arranged straight lines and a plurality of zigzag lines. Together, the straight lines and the zigzag lines may define a tessellation of parallelogram segments.

[0048] The term “tessellation” may herein especially refer to a pattern of (repeated) shape, that fit together closely without gaps or overlapping. Herein, the tessellation may especially be of parallelograms separated by the straight lines and the zigzag lines.

[0049] In embodiments, the parallelogram segments may vary, e.g., vary in size. However, generally, the parallelogram segments may be congruent, i.e., the parallelogram segments may have the shape and size as one another.

[0050] The straight lines and the zigzag lines may extend in perpendicular directions. In particular, the straight lines may be arranged parallel to the first axis Al and the zigzag lines may extend along the second axis A2, i.e., when moving from an folded configuration to an unfolded configuration, the straight lines may remain aligned with the first axis Al and the zigzag lines, which may correspond to the valley and peak ranges, may remain essentially arranged along the second axis A2.

[0051] Each straight line of the parallel straight lines may comprise a plurality of line segments. The line segments may especially be separated by zigzag lines, more especially by turn comers of the zigzag lines. In particular, for each straight line may apply that its line segments are altematingly first line segments and second line segments, i.e., excluding outer line segments, each first line segment is arranged between two second line segments and each second line segment is arranged between two first line segments.

[0052] Similarly, the zigzag lines may altematingly be first zigzag lines and second zigzag lines. Especially, the zigzag lines may altematingly be first zigzag lines and second zigzag lines in a direction parallel to the straight lines, e.g., in a direction along the first axis AE

[0053] In embodiments, each parallelogram segment may have a first segment side, a second segment side, a first zigzag side, and a second zigzag side. In particular, the first line segments may define the first segment sides (of the parallelogram segments). Similarly, the second line segments may define the second segment sides (of the parallelogram segments). Further, the first zigzag lines may define the first zigzag sides (of the parallelogram segments). Yet further, the second zigzag lines may define the second zigzag sides (of the parallelogram segments). Hence, each parallelogram segment may have four parallelogram sides, one of which is defined by a first line segment, one of which is defined by a second line segment, one of which is defined by a first zigzag line, and one of which is defined by a second zigzag line.

[0054] Each parallelogram segment may further have an obtuse interior angle cto between the first segment side and the first zigzag side. Given the symmetry of a parallelogram, the parallelogram segment may thus also have the obtuse interior angle cto between the second segment side and the second zigzag side. The term “obtuse angle” may herein refer to an angle larger than 90°. For instance, in embodiments, the obtuse angle cto may be selected from the range of 110° - 140°, such as from the range of 115° - 135°, especially from the range of 120° - 130°.

[0055] By extent, each parallelogram segment may have an acute interior angle aabetween the first segment side and the second zigzag side. Similarly, each parallelogram segment may further have the acute interior angle aabetween the second segment side and the first zigzag side. In particular, aa+ cto = 180°. In further embodiments, the acute interior angle aamay be selected from the range of 40° - 70°, such as from the range of 45° - 65°, especially from the range 50° - 60°. Foldable reflectors with parallelogram angles in these ranges may be particularly suitable for providing a symmetric beam shape. In particular, small acute interior angles aa. e.g., of 30°, may result in high intensities at large angles in a first plane (CO plane) along an optical axis of the light generating system, whereas large acute interior angles ota, e.g., of 75°, may result in high intensities at large angles in a second plane (C90) along the optical axis of the light generating system. In particular, the CO plane may be parallel to the first axis Ai and to the third axis A3, whereas the C90 plane may be parallel to the second axis A2 and to the third axis A3. Acute interior angles aain the range of 45° - 65° may provide a symmetric beam (good in both the CO and C90 planes). In particular, the unified glare ratio (UGR) score may be lower with an acute interior angle aain the range of 45° - 65° compared to smaller and larger angles. Values around 55° appear to result in particularly good (low) UGR scores.

[0056] In embodiments, the first folding elements may define the first line segments and the first zigzag lines. Similarly, the second folding elements may define the second line segments and the second zigzag lines.

[0057] As the first folding elements are arranged on the first side of the foldable reflector and as the second folding elements are arranged on the second side of the foldable reflector, each parallelogram segment may have two parallelogram sides defined on the first side of the foldable reflector and two parallelogram sides defined on the second side of the foldable reflector.

[0058] Hence, in specific embodiments, in the unfolded configuration applies that: in a superposition of the first side and the second side, the first folding elements and the second folding elements together define a folding element pattern, wherein the folding element pattern comprises a plurality of parallelly arranged straight lines and a plurality of zigzag lines, wherein the straight lines and the zigzag lines define a tessellation of the parallelogram segments, wherein: each straight line comprises a plurality of line segments separated by zigzag lines, wherein the line segments are altematingly first line segments and second line segments; the zigzag lines are altematingly first zigzag lines and second zigzag lines; each parallelogram segment has a first segment side, a second segment side, a first zigzag side, a second zigzag side, and an obtuse interior angle a0between the first segment side and the first zigzag side; the first line segments define the first segment sides; the second line segments define the second segment sides; the first zigzag lines define the first zigzag sides; and the second zigzag lines define the second zigzag sides; the first folding elements define the first line segments and the first zigzag lines; and the second folding elements define the second line segments and the second zigzag lines.

[0059] In further embodiments, for each parallelogram segment may apply that a length ratio between neighboring sides is selected from the range of 0.33 - 3, especially from the range of 0.5 - 2, such as from the range of 0.67 - 1.5. Hence, for each parallelogram segment may apply that a length ratio between the first segment side and the first zigzag side is selected from the range of 0.33 - 3, especially from the range of 0.5 - 2, such as from the range of 0.67 - 1.5.

[0060] As described above, the light generating device may comprise a plurality of light generating devices. In embodiments, the light generating system may comprise a first set of the light generating devices. The light generating devices of the first set may especially (all) be arranged on the first side of the foldable optics.

[0061] In the folded configuration, the light generating devices of the first set may especially be arranged within the valleys of the 3D shape. In particular, for each light generating device of a first set of the light generating devices may apply that the light generating device is arranged at a (closest) edge-to-edge distance duo from a valley bottom.

[0062] In embodiments, in the folded configuration the foldable reflector has a height H along the third axis A3. Especially, in such embodiments, the edge-to-edge distances duo may be (independently) selected from the range of 0 - 0.5*H, such as from the range of 0 - 0.25*H, especially from the range of 0 - 0.1*H, i.e., dno / H< 0.5, such as < 0.25, especially < 0.1.

[0063] In further embodiments, (at least part ol) the light generating devices of a first set of the light generating devices may be arranged aligned with the valley bottom. In particular, the light generating devices (of the first set) may be aligned with the valley bottom in a direction parallel to the third axis. In further embodiments, each light generating device of a first set of the light generating devices may be aligned with the valley bottom. In particular, each light generating device (of the first set) may be aligned with the valley bottom in a direction parallel to the third axis.

[0064] Especially, in embodiments, the valleys may comprise turn comers (or “turns”). In further embodiments, (at least part ol) the light generating devices of the first set may be aligned with a (respective) turn comer, especially in a direction parallel to the third axis. In further embodiments, each light generating device of the first set may be aligned with a turn comer, especially in a direction parallel to the third axis. Due to the zigzag patterns of the valleys, the valleys contain turn comers facing a first direction and turn comers facing a second direction. For a symmetric beam, it may be preferable for light sources to be similarly distributed among the turn comers facing different directions. Hence, in embodiments, the turn comers may comprise first turn comers and second turn comers, wherein the first turn comers and the second turn comers face opposite directions along the first axis Al. In such embodiments, m first turn comers may be aligned with a light generating device (along the third axis A3) and second turn comers may be aligned with a light generating device (along the third axis A3), especially wherein ni / n2 is selected from the range of 0.67 - 1.5, such as from the range of 0.8-1.25, especially from the range of 0.9-1.1.

[0065] In further embodiments, (at least part ol) the light generating devices of the first set may be arranged between adjacent turn comers (of a respective valley), especially arranged centrally between adjacent turn comers. In particular, the valleys may contain valley stretches between adjacent turn comers and, in embodiments, at least part ol) the light generating devices of the first set may be arranged along valley stretches, especially arranged centrally in valley stretches.

[0066] Due to the zigzag patterns of the valleys, the valley stretches may be oriented in a first stretch direction and in a second stretch direction. For a symmetric beam, it may be preferable for light sources to be similarly distributed among the valley stretches arranged along different directions. Hence, in embodiments, the valley stretches may comprise first valley stretches and second valley stretches, wherein the first valley stretches and the second valley stretches are arranged at an angle (or “are non-parallel”). In such embodiments, ns light generating device may be arranged along first valley stretches and light generating devices may be arranged along second valley stretches may be aligned with a light generating device (along the third axis A3), especially wherein ns / is selected from the range of 0.67 - 1.5, such as from the range of 0.8-1.25, especially from the range of 0.9-1.1.

[0067] In embodiments, the light generating devices may be configured to provide device light along an optical axis, especially in a single direction along the optical axis. For instance, the light generating devices may be point-like light generating devices, e.g., typical point-like mid-power LEDs. Such light generating devices (of the first set) may preferably be placed at the valley bottom. In embodiments, light emitting surface areas of the point-like light generating devices may have an equivalent circular diameter dr, wherein dno / dt < 3, such as < 2, especially < 1, including 0. Especially, the light generating devices (of the first set) may be arranged at the valley bottoms of the valleys.

[0068] In further embodiments, the light generating devices may be configured to provide device light in multiple directions. For instance, in embodiments, the light generating devices may comprise (LED) filaments. In such embodiments, it may be preferred if the light generating devices are arranged at a distance from the valley bottoms. Thereby, the light emitted towards the valley can be reflected by the foldable reflector and pass the filament on the way out of the valley (otherwise the filament may block a lot of the reflected light). In embodiments, the elongated filaments may have an equivalent circular filament diameter dr, wherein diio / dr is (independently) selected from the range of 0.5 - 7, such as from the range of 1 -5, especially from the range of 1-4.

[0069] Hence, in embodiments, (at least part ol) the light generating devices comprise elongated (LED) filaments, wherein in the folded configuration the elongated filaments are arranged along the valleys, wherein the elongated filaments have equivalent circular filament diameters dr. Especially wherein dno / dr is (independently) selected from the range of 1-5. In the unfolded configuration the elongated filaments may especially be arranged along the first zigzag lines.

[0070] Similarly, in embodiments, the light generating system may comprise a second set of the light generating devices. The light generating devices of the second set may especially (all) be arranged on the second side of the foldable optics. The light generating devices of the second set may be (essentially) analogous to the light generating devices of the first set, but may instead be arranged at the second side of the foldable reflector.

[0071] For instance, in the folded configuration, the light generating devices of the second set may especially be arranged within second valleys at the second side of the 3D shape. In particular, for each light generating device of a second set of the light generating devices may apply that the light generating device is arranged at a (closest) second edge-to- edge distance di2o from a second valley bottom (of a second valley). Especially, in the folded configuration the foldable reflector may have a height H along the third axis A3, wherein the second edge-to-edge distances d o is (independently) selected from the range of 0 - 0.5*H, such as from the range of 0 - 0.25*H, especially from the range of 0 - 0.1*H, i.e., d o / H < 0.5, such as < 0.25, especially < O.l.In further embodiments, (at least part ol) the light generating devices of a second set of the light generating devices may be arranged aligned with the second valley bottoms. In particular, the light generating devices (of the second set) may be aligned with the second valley bottoms in a direction parallel to the third axis. In further embodiments, each light generating device of a second set of the light generating devices may be aligned with a (respective) valley bottom. In particular, each light generating device (of the second set) may be aligned with the (respective) valley bottom in a direction parallel to the third axis. Especially, in embodiments, the second valleys may comprise second turn comers (or “second turns”). In further embodiments, (at least part of) the light generating devices of the second set may be aligned with a (respective) second turn comer, especially in a direction parallel to the third axis. In further embodiments, each light generating device of the second set may be aligned with a second turn comer, especially in a direction parallel to the third axis.

[0072] Due to the zigzag patterns of the valleys, the second valleys contain second turn comers facing a first direction and second turn comers facing a second direction. For a symmetric beam, it may be preferable for light sources to be similarly distributed among the second turn comers facing different directions. Hence, in embodiments, the second turn comers may comprise second side first turn comers and second side second turn comers, wherein the second side first turn comers and the second side second turn comers face opposite directions along the second axis Al. In such embodiments, i second side first turn comers may be aligned with a light generating device (along the third axis A3) and 1122 second side second turn comers may be aligned with a light generating device (along the third axis A3), especially wherein n2i / n22 is selected from the range of 0.67 - 1.5, such as from the range of 0.8-1.25, especially from the range of 0.9-1.1.

[0073] In embodiments, the light generating devices of the second set may be configured to provide device light along an optical axis, especially in a single direction along the optical axis. For instance, the light generating devices of the second set may be point-like light generating devices, e.g., typical point-like mid-power LEDs. In embodiments, light emitting surface areas of the point-like light generating devices may have an equivalent circular diameter dr, wherein di2o / dt < 3, such as < 2, especially < 1, including 0. Especially, the light generating devices (of the second set) may be arranged at the valley bottoms of valleys at the second side.

[0074] In further embodiments, the light generating devices of the second set may be configured to provide device light in multiple directions. For instance, in embodiments, the light generating devices of the second set may comprise (LED) filaments. In embodiments, the elongated filaments may have an equivalent circular filament diameter dr, wherein di2o / dr is (independently) selected from the range of 0.5 - 7, such as from the range of 1 -5, especially from the range of 1-4.

[0075] Hence, in embodiments, (at least part ol) the light generating devices of the second set may comprise elongated (LED) filaments, wherein in the folded configuration the elongated filaments are arranged along the valleys, wherein the elongated filaments have equivalent circular filament diameters dr, wherein d o / dr is (independently) selected from the range of 1 - 5. In the unfolded configuration the elongated filaments may especially be arranged along the second zigzag lines.

[0076] In further embodiments, the light generating devices of the first set and of the second set may comprise the same type of light generating devices, e.g., both may comprise point-like light generating devices, or both may comprise elongated (LED) filaments. In further embodiments, the light generating devices of the first set and of the second set may comprise different types of light generating devices, e.g., one may comprise point-like light generating devices and the other may comprise elongated (LED) filaments.

[0077] It will be clear to the person skilled in the art that the FWHM of a light output beam may depend on several parameters: the type of reflector (specular vs diffuse & reflectivity value itself), the angle at which it is folded out of the plane of the unfolded configuration, and the height of the source inside the valley (distance between valley bottom and source in the direction perpendicular to the plane of the unfolded reflector). In embodiments, the light generating system, especially the foldable reflector in the folded configuration, may be configured such that the light generating devices provide device light having a FWHM angle (P) selected from the range of 70° - 120°, especially from the range of 80° - 110°.

[0078] In embodiments, the foldable reflector may comprise a diffuse reflector. Especially, one or more of the first side and the second side of the foldable reflector may be diffuse reflectors, especially the first side and the second side of the foldable reflector may (both) be diffuse reflectors. In further embodiments, at least the first side of the foldable reflector may (both) be a diffuse reflector. Materials that are diffusely reflective are known in the art. For instance, in embodiments, the foldable reflector, especially at least the first side of the foldable reflector, may comprise a diffusely reflective material selected from the group comprising white paper, injection moldable materials with filled clear plastics, polycarbonate (PC) filled with Titanium Oxide (TiO2), poly(methyl methacrylate) (PMMA) with particles of different index material (PC, Si), silicone filled with small ceramic / oxide particles, “surface” reflective materials, painted / coated plastic, metal, glass, with a coating materials as described above, and “foam like” clear plastics with a high fraction of air cavities, e.g., Toray, Sabie, MCPET, and GoreTEX. Diffuse reflectors may provide a high reflectivity and may provide a particularly soft (comfortable) appearance.

[0079] In further embodiments, the foldable reflector may comprise a specular reflector. Especially, one or more of the first side and the second side of the foldable reflector may be specular reflectors, especially the first side and the second side of the foldable reflector may (both) be specular reflectors. In further embodiments, at least the second side of the foldable reflector may (both) be a specular reflector. Materials that are specularly reflective are known in the art. For instance, in embodiments, the foldable reflector, especially at least the second side of the foldable reflector, may comprise a specularly reflective material selected from the group comprising an Al or Ag plate, preferably with optical coating (to protect the metal layer from oxidation and / or to enhance reflectivity), a plastic with an Al or Ag coating, a dielectric mirror, and an enhanced specular reflector (ESR) foil. Specular reflectors may produce more narrow beams and better defined beam cutoff.

[0080] In further embodiments, the foldable reflector may be partly diffusely and partly specularly reflective. For instance, the foldable reflector, especially the first side, or especially the second side, may comprise a metal reflector with a rough surface texture, or white plastic with a glossy finish.

[0081] In further embodiments, the first side of the foldable reflector may be diffusely reflective and the second side of the foldable reflector may be specularly reflective (or vice versa). With such a foldable reflector, a user may select (e.g., during assembly) whether to use the specularly or the diffusely reflecting side. Alternatively, in such embodiments, at least part of the plurality of light generating devices may be arranged on the second side of the foldable reflector, i.e., both the specularly and the diffusely reflective sides may be used.

[0082] 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.

[0083] In a further aspect, the invention may provide a lighting device comprising the light generating system of the invention. The lighting device may be selected from the group of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device. 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.

[0084] Instead of the terms “lighting device” or “lighting system”, and similar terms, also the terms “light generating device” or “light generating system”, (and similar terms), may be applied. A lighting device or a lighting system may be configured to generate device light (or “lighting device light”) or system light (“or lighting system light”).

[0085] BRIEF DESCRIPTION OF THE DRAWINGS

[0086] 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:

[0087] Figs. 1A-B schematically depict embodiments of the light generating system.

[0088] Figs. 2A-B schematically depict embodiments of the light generating system with the foldable reflector in different positions.

[0089] Figs. 3A-B schematically depict beam profiles obtainable with the light generating system of the invention.

[0090] Fig. 4 schematically depicts embodiments of lighting devices.

[0091] The schematic drawings are not necessarily to scale.

[0092] DETAILED DESCRIPTION OF THE EMBODIMENTS Fig. 1 schematically depicts an embodiment of a light generating system 1000 comprising a foldable reflector 200 and a plurality of light generating devices 100. In particular, in the depicted embodiment, the light generating devices 100 comprise filaments 130 represented by thick lines. The foldable reflector 200 has (a) a first side 210 comprising first folding elements 215 and (b) a second side 220 comprising second folding elements 225 (see Fig. IB). In particular, the first side may be the side seen in Fig. 1 A, whereas the second side may be the opposite side, i.e., the “bottom side” of the foldable reflector 200 as depicted. In the depicted embodiment, (at least part ol) the light generating devices 100 are arranged at the first side 210. Especially, in such embodiments, the first side 210 may be reflective, such as reflective for light source light 111 provided by the light generating devices 100. The first folding elements 215 and the second folding elements 225 may be configured to allow folding (and unfolding) of the foldable reflector 200, especially at the folding elements

[0093] 215.225. The foldable reflector 200 may be switchable between a (fully) unfolded configuration 201 and a folded configuration 202. Especially, by folding at the first folding elements 215 and the second folding elements 225 the foldable reflector 200 may be switchable between a fully unfolded configuration 201 (see Fig. IB) and a folded configuration 202 as schematically depicted in Fig. 1A. In the unfolded configuration, the foldable reflector 200 may have a planar shape, i.e., the foldable reflector 200 may be (essentially) flat. In the depicted embodiment, in the folded configuration, the foldable reflector 200 has a 3D shape comprising a repeating structure of parallelogram segments 400. Along a first axis Ai the 3D shape comprises alternating valleys 266 and peak ranges 267 at the first side 210, wherein the valleys 266 and peak ranges 267 extend along a second axis A2 perpendicular to the first axis Ai. The valleys 266 and the peak ranges 267 have zigzag shapes. Further, the repeating structure may repeat along the first axis Ai and along the second axis A2. Although the foldable reflector 200 is folded along the folding elements

[0094] 215.225, the individual parallelogram segments 400 are flat (or “planar”).

[0095] In the depicted embodiments, the turn comers 265 comprise first turn comers 265a and second turn comers 265b. Especially, the first turn comers 265a and the second turn comers 265b face opposite directions along the first axis Ai. In the depicted embodiments, the light generating devices 100 comprise elongated LED filaments 130, wherein in the folded configuration the elongated LED filaments 130 are arranged along the valleys 266. In further embodiments, m first turn comers 265a may be aligned with a light generating device 100 and second turn comers 265b may be aligned with a light generating device 100 (also see Fig. 2A), especially aligned in a direction parallel to a third axis A3 perpendicular to the first axis Ai and perpendicular to the second axis A2, and especially wherein m / n2 is selected from the range of 0.8-1.25.

[0096] Further, in the depicted embodiment, each parallelogram segment 400 has two parallelogram comers 445 having an acute interior angle aa, especially wherein the acute interior angle aais selected from the range of 45° - 65°, such as from the range of 50° - 60°. Each parallelogram segment 400 may further have two parallelogram comers 445 having an obtuse interior angle cto, especially wherein the obtuse interior angle a<> is selected from the range of 115° - 135°, such as from the range of 120° - 130°.

[0097] Fig. IB schematically depicts an embodiment of the light generating system 1000 in the unfolded configuration 201. In particular, Fig. IB schematically depicts a superposition 20 of the first 210 and the second side 220 of the light generating system 1000, especially of the foldable reflector 200. In the superposition 20, the first folding elements 215 and the second folding elements 225 together define a folding element pattern 500, i.e., the first folding elements 215 on the first side 201 of the foldable reflector 200 define a folding element pattern 500 together with the second folding elements 225 on the second side 202 of the foldable reflector 200. The folding element pattern may especially comprise a Miura fold pattern. In particular, the folding element pattern 500 comprises a plurality of parallelly arranged straight lines 510 and a plurality of zigzag lines 560, wherein the straight lines 510 and the zigzag lines 560 (together) define a tessellation of parallelogram segments 400. In particular, each straight line 510 comprises a plurality of line segments 515 separated by zigzag lines 510, especially separated by turn comers 265 of the zigzag lines 560. The turn comers 265 of the zigzag lines 560 may form turn comers 265 of the valleys 266 and of the peaks 267 in the folded configuration 201. The line segments 515 (of the same straight line 510) are altematingly first line segments 511 and second line segments 512. Similarly, the zigzag lines 560 are altematingly first zigzag lines 566 and second zigzag lines 567, especially in a direction parallel to the straight lines 510, e.g., in a direction along the first axis Ai. Each parallelogram segment 400 may have a first segment side 411, a second segment side 412, a first zigzag side 466, a second zigzag side 467, an obtuse interior angle (cto) between the first segment side 411 and the first zigzag side 466, and an acute interior angle (aa) between the first segment side 411 and the second zigzag side 412. As the parallelogram segments 400 have a parallelogram shape, the parallelogram segments may further have the obtuse interior angle (a0) between the second segment side 412 and the second zigzag side 467 and the acute interior angle (ou) between the second segment side 412 and the first zigzag side 466. In the depicted embodiment, the first line segments 511 define the first segment sides 411 (of the parallelogram segments 400) and the second line segments 512 define the second segment sides 412 (of the parallelogram segments 400). Similarly, the first zigzag lines 566 define the first zigzag sides 466 (of the parallelogram segments 400) and the second zigzag lines 567 define the second zigzag sides 467 (of the parallelogram segments 400). Further, the first folding elements 215 define the first line segments 511 and the first zigzag lines 566, whereas the second folding elements 225 define the second line segments 512 and the second zigzag lines 567.

[0098] In the depicted embodiment, each parallelogram segment 400 is a mirror image of each neighboring parallelogram segment 400 sharing a straight line segment 515.

[0099] Further, in the depicted embodiment, the light generating devices 110 comprise elongated filaments 130 arranged along the first zigzag lines 566. Hence, upon folding of the depicted foldable reflector 200 into the folded configuration 202, the light generating system 1000 may comprise elongated filaments 130 in the valleys 266 at the first side 201.

[0100] In embodiments, for each parallelogram segment 400 may apply that a length ratio between neighboring sides is selected from the range of 0.33 - 3, such as from the range of 0.5 - 2, especially from the range of 0.67 - 1.5. For instance, for each parallelogram segment 400 may apply that a length ratio between a first segment side 411 and a first zigzag side 466 is selected from the range of 0.33 - 3, such as from the range of 0.5 - 2, especially from the range of 0.67 - 1.5.

[0101] Fig. 2A schematically depicts cross-sections of a further embodiment of the light generating system 1000. In particular, Fig. 2A schematically depicts a cross-section of the light generating system 1000 with the folded reflector 200 in the unfolded configuration 201 and a cross-section with the folded reflector 200 in the folded configuration 202.

[0102] In the depicted embodiment, five different options for light generating devices 110,110a, 110b, 110c, 11 Od, 1 lOe are schematically depicted. It will be clear to the person skilled in the art that these examples are not exhaustive and that alternative options may be possible. In practice, one or two different options may be selected for the light generating devices, e.g., the same option throughout or a first option at the first side 210 and a second option at the second side 220 of the foldable reflector 200

[0103] The first light generating device 100,100a represent a point light source arranged on a parallelogram segment 400 in the vicinity of a first folding element 215. After folding of the foldable reflector 200 into the folded configuration 202, the first light generating device 100,100a is arranged in a valley 266 of the folded reflector 200 at a small distance from the valley bottom. For instance, the first light generating device 100,100a may be an LED mounted on a reflector, e.g. white coated PCB. Such LEDs may be placed close to the valley bottom. The first light generating device 100, 100a has a light emitting surface having a circularly equivalent diameter dr.

[0104] The second light generating device 100,100b is an elongated filament 130 arranged in a valley 266 on the second side 220 after folding into the folded configuration. The second light generating device 100,100b may he in the valley 266 (depending on the gravitational direction) or may, for instance, be attached with a sticky material, .e.g., with (transparent) glue. In such embodiments, electrical contacts may be out of the plane of the drawing (to the next filament, or to the side of the reflector sheet). Further, either a single flexible filament may be placed in the zigzag valley (also see Fig. 1A) or a chain of rigid filaments flexibly connected by wires / bendable rods may be placed in the zigzag valley (also see Fig. IB). In further embodiments, the light generating devices 100 may be enveloped or clamped by the foldable reflector 200. The second light generating device 100,100b has a circularly equivalent filament diameter dr.

[0105] The third light generating device 100,100c is a point light source arranged into a valley 266 after folding of the foldable reflector 200 into the folded configuration 202. The third light generating device 100,100c may be arranged on a fixed zigzag shaped printed circuit board (PCB) for a predefined folded configuration 202, or onto a small PCB to provide a flexible arrangement, also with respect to folding angle, for instance using a plurality of small PCBs that are connected in a flexible way (e.g. by wires).

[0106] The fourth light generating device 100,100d is an elongated filament 130 arranged in a valley 266 on the second side 220 after folding into the folded configuration. In the depicted embodiment, the elongated filament is attached to a standing wire (or “rod”) that sticks through the foldable reflector 200. The electrical & mechanical support may be at the backside (here: at the first side 210) of the foldable reflector 200: either fixed for folded configuration 202 of flexibly connected units, or freedom to place contacts by pushing (sharp) rods through the foldable reflector 200. The fourth light generating device 100,100d has a circularly equivalent filament diameter dr.

[0107] The fifth light generating device 100,100e is a point light source arranged to align with a through-hole in the foldable reflector 200. Hence, in embodiments, the foldable reflector 200 may comprise through-holes, especially in a regular arrangement along the folding elements 215,225, such as in a regular arrangement along the first folding elements 215. In the depicted embodiment, the light generating system 1000 may thus comprise a PCB with LEDs below the foldable reflector 200, wherein the foldable reflector has holes aligned with the LEDs. In such embodiments, the foldable reflector 200 may especially be configured to be folded into a predefined fold state (as the LED positions may be fixed). The fifth light generating device 100,100e has a light emitting surface having a circularly equivalent diameter dr.

[0108] Further, in the depicted embodiment, the light generating system 1000 comprises a first set 110 of light generating devices 100. Specifically, the first set 110 comprises the third light generating device 110,110c and the fourth light generating device 110,1 lOd. For each light generating device 100 of the first set 110 of the light generating devices 100 applies that: along a third axis A3 the light generating device 100 is arranged at a (closest) edge-to-edge distance duo from a valley bottom 268. In particular, the third axis A3 is perpendicular to the plane 250. Further, the third axis A3 may be perpendicular to the first axis Ai and to the second axis A3. In the depicted embodiment, in the folded configuration the foldable reflector has a height H along the third axis A3, wherein the edge-to-edge distances duo are (independently) selected from the range of 0 - 0.5*H, such as from the range of 0 - 0.25*H, especially from the range of 0 - 0.1 *H. Further, for each light generating device 100 of the first set 110 applies that: in a superposition along the third axis A3 the light generating device 100 is aligned with a turn comer 265. In the depicted embodiment, wherein the foldable reflector is in the unfolded configuration, the foldable reflector 200 defines a plane 250. The first folding elements 215 and the second folding elements 225 are configured to allow folding between adjacent parallelogram segments 400 (of the parallelogram segments 400) such that in the folded configuration 202 (a parallelogram plane defined by) each parallelogram segment 400 is arranged at a smallest angle 0 to the plane 250. In embodiments, 0 may be selected from the range of 45° - 75°, such as from the range of 50° - 70°, especially from the range of 55° - 65°. Especially, for at least 80% of (a total number ol) the parallelograms segments 400 applies that the parallelogram 400 is arranged at the smallest angle (0) with the plane.

[0109] Further, in the depicted embodiment, the first folding elements 215 and the second folding elements 225 are grooves. Especially, the first folding elements 215 and the second folding elements 225 have a V-shaped groove shape. In further embodiments, the groove shape may be a U-shapes or a rectangular shape. Further, in the unfolded configuration 201 the foldable reflector 200 has a thickness D, wherein the first folding elements 215, especially the first folding elements 215 defining the first line segments 511, and the second folding elements 225, especially the second folding elements 225 defining the second line segments 512, have a (same) segment groove depth ds. In embodiments, ds / D is selected from the range of 0.05 - 0.95, such as from the range of 0.1 - 0.9, especially from the range of 0.2 - 0.8.

[0110] The first folding elements 215 and the second folding elements 225 especially have V-shapes with internal angles 0v, wherein 0v = 2*0.

[0111] Fig. 2B schematically depicts cross-sections of a further embodiment of the light generating system 1000. In particular, Fig. 2B schematically depicts cross-sections of the light generating system 1000 in two different folded configurations 202. In particular, in the depicted embodiment, a folding state is kept in place by a lighting housing 1010, especially by a movable light exit window 1011. In particular, in the depicted embodiment, a height H of the folding state may be controlled by moving the light exit window 1011. Alternatively or additionally, a width (perpendicular to the height H) of the folding state may be controlled, such as defined by a width in a lighting housing 1010 (see element 200 in Fig. 4). In further embodiments, the lighting housing 1010 may have an adjustable width 1010. Hence, in embodiments, the foldable reflector 200 may be kept in a (specific) folding state by a lighting housing 1010.

[0112] Fig. 3A schematically depicts a simulated luminous intensity of a beam provided with an embodiment of the light generating system 1000. Specifically, the simulation correspond to a light generating system 1000 with the foldable reflector 200 in the folded state, and wherein two point-like light generating devices 100 were arranged in turn comers 265 facing opposite directions, i.e., with LEDs at valley bends with opposite directions a beam having a quadrant symmetry can be provided. The graph at the right side of Fig. 3A indicates the luminous intensity I (in candela) versus count C.

[0113] Fig. 3B schematically depicts a simulated luminous intensity of a beam provided with a further embodiment of the light generating system 1000. Specifically, the simulation correspond to a light generating system 1000 with the foldable reflector 200 in the folded state, and wherein elongated LED filaments 130 were arranged along the valleys 266, i.e., with a chain of LED filaments stretched along valeys of the folded reflector a smoother beam shape closer to a rotationally symmetric shape can be provided. The graph at the right side of Fig. 3B indicates the luminous intensity I (in candela) versus count C.

[0114] The luminous intensity distributions of Fig. 3A-B were obtained by monte carlo ray tracing simulations with the LightTools software package from Synopsys. The reflector was modeled as a 95% Lambertian reflector, 5% absorption. The folded reflector shape was created with mechanical CAD software. The LEDs were modeled by Lambertian square emitting surfaces and the LED filaments as Lambertian emitting cylinders.

[0115] 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. 3 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Hence, Fig. 3 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device, 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, 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.

[0116] The term “plurality” refers to two or more.

[0117] 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%.

[0118] The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’.

[0119] 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".

[0120] 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.

[0121] 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.

[0122] 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.

[0123] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0124] 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”.

[0125] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

CLAIMS:

1. A light generating system (1000) comprising a foldable reflector (200) and a plurality of light generating devices (100), wherein the foldable reflector (200) has (a) a first side (210) comprising first folding elements (215) and (b) a second side (220) comprising second folding elements (225), wherein a first set of the light generating devices (100) are arranged at the first side (210) and are configured to provide device light (101), wherein the first side (210) is reflective for the device light (101), and wherein the first folding elements (215) and the second folding elements (225) are configured to allow folding of the foldable reflector (200), wherein the foldable reflector (200) is switchable between an unfolded configuration (201) and a folded configuration (202), wherein: in the unfolded configuration (201) the foldable reflector (200) has a planar shape; and in the folded configuration (202) the foldable reflector (200) has a 3D shape comprising a repeating structure of parallelogram segments (400), wherein along a first axis (Ai) the 3D shape comprises alternating valleys (266) and peak ranges (267) at the first side (210), wherein the valleys (266) and peak ranges (267) extend along a second axis (A2) perpendicular to the first axis (Ai), and wherein the valleys (266) and the peak ranges (267) have zigzag shapes, wherein the first set of light generating devices (100) comprise elongated LED filaments (130), wherein in the folded configuration (202) the elongated LED filaments (130) are arranged along the valleys (266).

2. The light generating system (1000) according to claim 1, wherein in the unfolded configuration (201): in a superposition (20) of the first side (210) and the second side (220), the first folding elements (215) and the second folding elements (225) together define a folding element pattern (500), wherein the folding element pattern (500) comprises a plurality of parallelly arranged straight lines (510) and a plurality of zigzag lines (560), wherein the straight lines (510) and the zigzag lines (560) define a tessellation of the parallelogram segments (400), wherein:each straight line (510) comprises a plurality of line segments (515) separated by zigzag lines (510), wherein the line segments (515) are altematingly first line segments (511) and second line segments (512); the zigzag lines (560) are altematingly first zigzag lines (566) and second zigzag lines (567); each parallelogram segment (400) has a first segment side (411), a second segment side (412), a first zigzag side (466), a second zigzag side (467), and a first obtuse angle (a0) between the first segment side (411) and the first zigzag side (466); the first line segments (511) define the first segment sides (411); the second line segments (512) define the second segment sides (412); the first zigzag lines (566) define the first zigzag sides (466); and the second zigzag lines (567) define the second zigzag sides (467); the first folding elements (215) define the first line segments (511) and the first zigzag lines (566); and the second folding elements (225) define the second line segments (512) and the second zigzag lines (567).

3. The light generating system (1000) according to any one of the preceding claims, wherein in the folded configuration (202) the foldable reflector (200) has a height H along a third axis (A3), wherein the third axis (A3) is perpendicular to the first axis (Ai) and to the second axis (A2), wherein for each light generating device (100) of a first set (110) of the light generating devices (100) applies that: the light generating device (100) is arranged at an edge-to-edge distance (duo) from a valley bottom (268) of a valley (266), wherein dno / H is selected from the range of <0.25.

4. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system comprises a second set of the light generating devices arranged on the second side of the foldable optics.

5. The light generating system (1000) according to claim 4, wherein the second set of light sources comrpises LED filaments.

6. The light generating system (1000) according to any one of the preceding claims 1-2, wherein the elongated filaments (130) have an equivalent circular filamentdiameter dr, wherein for each light generating device (100) of a first set (110) of the light generating devices (100) applies that: the light generating device (100) is arranged at an edge-to-edge distance (duo) from a valley bottom (268) of a valley (266), wherein dno / dr is selected from the range of 1-5.

7. The light generating system (1000) according to any one of the preceding claims, wherein each parallelogram segment (400) has an acute interior angle (aa) selected from the range of 45° - 65°.

8. The light generating system (1000) according to any one of the preceding claims, wherein for each parallelogram segment (400) applies that a length ratio between neighboring sides is selected from the range of 0.5 - 2.

9. The light generating system (1000) according to any one of the preceding claims, wherein in the unfolded configuration (201) the foldable reflector (200) defines a plane (250), wherein the first folding elements (215) and the second folding elements (225) are configured to allow folding between adjacent parallelogram segments (400) such that in the folded configuration (202) at least 70% of the parallelograms segments are arranged at a smallest angle (0) to the plane (250), wherein 0 is selected from the range of 50° - 70°.

10. The light generating system (1000) according to claims 7 and 9, wherein the acute interior angle aais selected from the range of 50° - 60°, and wherein 0 is selected from the range of 55° - 65°.

11. The light generating system (1000) according to any one of the preceding claims 9-10, wherein in the folded configuration (202) applies that: each parallelogram segment (400) is flat; and at least 95% of the parallelograms segments (400) are arranged at the smallest angle (0) with the plane (250).

12. The light generating system (1000) according to any one of the preceding claims 1-8, wherein the foldable reflector (200) is switchable between the unfolded configuration (202) and a fully collapsed configuration via the folded configuration (201), wherein in the fully collapsed configuration the foldable reflector (200) has a 3D shapecomprising a repeating structure of parallelogram segments (400), wherein surfaces of adjacent parallelogram segments (400) abut each other.

13. The light generating system (1000) according to any one of the preceding claims, wherein the first folding elements (215) and the second folding elements (225) are grooves having a groove shape selected from the group comprising V-shapes, U-shapes and rectangular shapes, and wherein in the unfolded configuration (201) the foldable reflector (200) has a thickness (D), wherein the first folding elements (215) defining the first line segments (511) and the second folding elements (225) defining the second line segments (512) have a segment groove depth (ds), and wherein ds / D is selected from the range of 0.05- 0.95.

14. The light generating system (1000) according to any one of the preceding claims, wherein the first side (210) of the foldable reflector (200) is diffusely reflective, wherein the second side (220) of the foldable reflector (200) is specularly reflective, and wherein at least part of the plurality of light generating devices 100 is arranged on the second side (220) of the foldable reflector (200).

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, and an optical wireless communication device, comprising the light generating system (1000) according to any one of the preceding claims.

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