Lighting device with light mixing chamber

Abstract

A lighting device (1) comprising a lampshade (2) and a light engine (3) enclosed within the lampshade (2), the light engine (3) comprising: a housing having two opposite side walls (7) extending from a base (4) and defining a light exit window (11) arranged opposite the base (4); the invention relates to a lighting device (1) comprising a base (4), two opposite side walls (7) and a cover (8), a first light source comprising a plurality of first LEDs (5) arranged on a first 5 carrier (6), the first light source being arranged inside the housing and arranged to emit light towards a light exit window (11), the lighting device (1) further comprising a light mixing chamber (10) formed between the base (4), the two opposite side walls (7) and the cover (8), and a cover (8) extending between the two opposite side walls (7) and closing the light exit window (11), 10, wherein the cover (8) is (i) part of the lampshade (2); or (ii) a part of a housing of the light engine (3) wherein the cover (8) faces a part (2a) of the lampshade (2), and wherein the light mixing chamber (10) has a spiral or coiled shape.

Description

Technical Field

[0001] The present invention relates to a lighting device using a light mixing chamber to provide a specific aesthetic effect. Background Art

[0002] Light-emitting diodes (LEDs) continue to attract attention for lighting applications. Compared to incandescent, fluorescent, and neon bulbs, LEDs offer numerous advantages, including longer lifespans, lower power consumption, and higher efficiency (the ratio between light energy and heat energy). LED strip lights, in particular, are gaining acclaim for their decorative appeal.

[0003] LED light strips or light bars are usually straight. Curling them into a coiled shape makes it possible to fit a longer length of LED light strip or light bar into a small diameter tube when installed in a tube.

[0004] For example, US 2015 / 0285472 discloses such a structure. Although the appearance of such a lighting device with a curved LED light strip is acceptable, it has not been optimized in terms of providing a specific aesthetic effect.

[0005] US 2022 / 228715 discloses a lighting device having a light strip comprising a plurality of solid-state light sources and an elongated reflector for reflecting light emitted by the light strip. The reflector has a longitudinal groove within which the light strip is arranged, such that the reflector and the light strip extend longitudinally along a common, three-dimensionally curved path. Summary of the Invention

[0006] It is therefore an object of the present invention to provide a lighting device exhibiting an improved decorative lighting effect.

[0007] To this end, a lighting device is provided. The lighting device includes a lampshade enclosing a coiled or spiral-shaped light mixing chamber. A first light source (such as an LED light strip or LED light bar) is disposed on a carrier (such as a flexible carrier). The carrier is located at the base of the light mixing chamber, which is opposite the light exit window of the light mixing chamber.

[0008] In an operating state, the lighting device emits light (such as white light having a correlated color temperature in the range of 1800K to 6500K, and / or light having a color rendering index of at least 80).

[0009] The mixing chamber provides a light effect that can be seen on the outer surface of the lampshade, the light effect taking the form of a spiral, a coil or a swirl, while preventing flare from the LEDs. The light effect can even be a pixelated light effect.

[0010] More specifically, the present invention relates to a lighting device comprising a lampshade and a first light engine encapsulated in the lampshade.

[0011] The first light engine includes: a housing having two opposite side walls (i.e., two side walls opposite to each other) extending from a base and defining a light exit window arranged opposite to the base; and a first light source, the first light source including a plurality of first LEDs, the plurality of first LEDs being arranged on a first carrier, wherein the first light source is at least partially arranged within the housing and is arranged to emit light toward the light exit window.

[0012] The lighting device further comprises a light mixing chamber formed between the base, the two side walls and a cover extending between the two side walls and closing the light exit window.

[0013] The cover is either part of the lamp housing or part of the first light engine housing. When the cover is part of the lamp housing, the cover is the first portion of the lamp housing. When the cover is part of the first light engine housing, the cover faces the first portion of the lamp housing. Throughout the remainder of this specification, references to the "first portion of the lamp housing" refer to either the cover (if the cover is part of the lamp housing) or the portion of the lamp housing that faces the cover (if the cover is part of the first light engine housing).

[0014] The light mixing chamber has a coiled or spiral shape.

[0015] The cover extends between the two side walls and closes the light exit window. For this purpose, the cover can either be inserted between the two side walls or it can be adjacent to the respective ends of the two side walls.

[0016] The first portion of the lampshade may be transparent. If the cover is part of the lampshade, the first portion of the lampshade is the cover, and thus the cover is transparent. If the cover is part of the first light engine housing, the first portion of the lampshade is the portion of the lampshade facing the cover. In this case, not only the first portion but also the cover may be transparent.

[0017] The cover and the two side walls may have different optical properties to change the visible light effects through the lampshade.

[0018] In a first variation, the cover is a diffuser having a first reflectivity R1, and each of the two opposing side walls has a second reflectivity R2, wherein the second reflectivity R2 is at least 20% greater than the first reflectivity R1, such as at least 30% greater than the first reflectivity R1, or at least 40% greater than the first reflectivity R1, or at least 50% greater than the first reflectivity R1. In other words, R2>R1+20%, such as R2>R1+30%, or R2>R1+40%, or R2>R1+50%. The second reflectivity R2 of the side walls can be at least 70%, such as at least 80%, or at least 85%, or at least 88%, or at least 90%.

[0019] The first variant ensures that in operation, most of the light emitted by the plurality of LEDs exits the mixing chamber and passes through the lamp housing so that a serpentine or spiral light effect is visible on the outer surface of the lamp housing as a relatively high brightness area surrounded by a relatively low brightness area.

[0020] In a second embodiment, the cover is a diffuser having a first reflectivity R1, and each of the two opposing side walls has a second reflectivity R2, wherein the second reflectivity R2 is at least 20% less than the first reflectivity R1, such as at least 30% less than the first reflectivity R1, or at least 40% less than the first reflectivity R1, or at least 50% less than the first reflectivity R1. In other words, R2 < R1 - 20%, such as R2 < R1 - 30%, or R2 < R1 - 40%, or R2 < R1 - 50%. The first reflectivity R1 of the cover may be in the range of 30% to 65%, such as in the range of 35% to 60%, or in the range of 40% to 55%. The second reflectivity R2 of the side walls may be less than 28%, such as less than 25%, or less than 23%.

[0021] The second variant ensures that in operation, most of the light emitted by the plurality of LEDs exits the mixing chamber and passes through the lampshade so that a serpentine or spiral light effect is visible on the outer surface of the lampshade as a relatively low brightness area surrounded by a relatively high brightness area.

[0022] In each of the first and second variations, part of the light emitted by the first light source is not reflected but instead passes through the two opposing side walls and / or the diffusive cover. The light absorption rate of the two side walls and / or the diffusive cover may be less than 3%, such as less than 2%, or less than 1%.

[0023] In each of the first and second variations, the first reflectivity R1 of the cover may be in the range of 25% to 45%, such as in the range of 28% to 42%, or in the range of 30% to 40%.

[0024] In a third variant, the cover is a diffuser and each of the two opposing side walls is transparent.The third variant further improves the visibility of the coiled or spiral light effect on the outer surface of the lampshade.

[0025] The cover is either a part of the lampshade or a part of the first light engine housing. When the cover is a part of the lampshade, the cover is the first part of the lampshade. When the cover is a part of the first light engine housing, the cover faces the first part of the lampshade.

[0026] Adjacent to the first portion (which either constitutes the cover or faces the cover), the lamp cover may comprise a second portion separate from the first portion, wherein the first and second portions of the lamp cover have different optical properties.

[0027] The first portion of the lampshade and / or the cover may be transparent, while the second portion of the lampshade is light diffusing, or the first portion of the lampshade and / or the cover may be light diffusing, while the second portion of the lampshade is transparent.

[0028] The first light engine comprises a housing having two opposing sidewalls extending from a base and defining a light exit window disposed opposite the base. The first light engine further comprises a first light source comprising a plurality of first LEDs. The first light source is at least partially disposed within the housing and is arranged to emit light toward the light exit window.

[0029] The plurality of first LEDs are arranged on a first carrier. As long as the first light source is at least partially disposed within the housing and arranged to emit light toward the light exit window, the first carrier may be at least partially disposed outside the housing, such as at least partially disposed on the base of the housing. This arrangement allows for improved thermal management, thereby increasing reliability and efficiency. The base may be provided with a plurality of holes to accommodate the plurality of first LEDs protruding through the holes.

[0030] The swirl light effect can have a gradient in intensity and / or color and / or correlated color temperature. This can be achieved by using a pixelated LED light strip that provides a gradient in intensity and / or color and / or correlated color temperature. Alternatively or additionally, this can also be achieved by using a lampshade or cover whose reflectivity and transmittance vary in a given direction.

[0031] More specifically, the optical properties of the first portion of the lampshade and / or the cover can vary along the spiral or helical shape of the light mixing chamber. Additionally or alternatively, the optical properties of the first portion of the lampshade and / or the cover can vary along a direction parallel to and / or perpendicular to the longitudinal axis of the lighting device. This variation can occur gradually or in a step-like manner and can be used to further enhance the decorative light effect.

[0032] The light mixing chamber may include at least three rings, wherein at least one ring has N optical property variations, where N is greater than or equal to five.

[0033] In order to obtain the desired optical property variation, the thickness of the first portion of the lampshade and / or the cover can be locally reduced or increased. Additionally or alternatively, the first portion of the lampshade and / or the cover can contain reflective particles, wherein the concentration and / or type of the reflective particles vary locally.

[0034] The lighting device includes a first light source comprising a plurality of first LEDs. Each of the plurality of first LEDs is individually controllable. The lighting device may further include a controller configured to individually control the LEDs of the plurality of first LEDs to vary the intensity and / or color point of the LEDs, thereby achieving a light gradient along a coiled or spiral shape of the light mixing chamber.

[0035] The first light source may include an LED light bar or an LED light belt.

[0036] LED light strips typically include an array of LEDs arranged, mounted and / or mechanically coupled to a carrier or substrate. The term "array" refers to a linear arrangement of LEDs or a chain of LEDs, for example 20 or more LEDs. The carrier or substrate is configured to support the LEDs and can be rigid or flexible. LED light strips typically also include an encapsulation that encapsulates the array of LEDs, wherein the encapsulation includes a light-transmitting material and, optionally, a luminescent material for at least partially converting light emitted by the LEDs. The term "encapsulation" refers to an elongated material, element, arrangement, etc. that is configured or arranged to at least partially surround, encapsulate and / or enclose an array of LEDs. The term "light-transmitting material" refers to a material, composition, and / or substance that is configured to transmit light.

[0037] The lighting device may further include a second light engine comprising a second light source. The second light engine may be at least partially enclosed by the first light engine, and may also be at least partially enclosed by the first light engine. The second light source may be an LED light bar. In other words, the second light engine may be an LED light bar.

[0038] At least a portion of the lampshade and the housing can be manufactured by 3D printing.

[0039] Other objects, features and advantages of the present invention will become apparent when studying the following detailed disclosure, the drawings and the appended claims.Those skilled in the art will realize that different features of the present invention can be combined to create embodiments other than those described in the following. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] These and other aspects of the invention will now be described in more detail, with reference to the accompanying drawings, which show embodiment(s) of the invention.

[0041] Figure 1 shows a perspective view of a lighting device, Figure 2 Shown Figure 1 A perspective view of a portion of the light engine enclosed in a lampshade in the lighting device shown. Figure 3 Schematically shows a partial cross-sectional view of a first type of lighting device, Figure 4 A partial cross-sectional view of a second type of lighting device is schematically shown. Figure 5 The arrangement of the LED light strip on the carrier is shown. DETAILED DESCRIPTION

[0042] Figure 1 A lighting device 1 is shown, which includes a lampshade 2 and a first light engine 3 encapsulated in the lampshade 2 .

[0043] Figure 2 The figure shows a portion of the first light engine 3 encapsulated in the lampshade 2 of the lighting device 1 .

[0044] The first light engine 3 comprises a housing having a base 4 and two opposite side walls 7 extending from the base 4 and defining a light exit window 11 arranged opposite to the base 4 .

[0045] The first light engine 3 further comprises a first light source on a carrier 6 arranged on the base 4 of the housing. The first light source comprises a plurality of LEDs 5 arranged on the carrier 6, such as in the form of an LED strip or a LED light belt.

[0046] The light exit window 11 is closed by a cover 8 .

[0047] like Figure 3 As schematically shown, in a first variation of the lighting device 1 , the cover 8 is the first part 2 a of the lampshade 2 .

[0048] like Figure 4 As shown schematically and as Figure 1 As shown, in the second variation of the lighting device, the cover 8 is different from the lampshade 2 and is a part of the housing of the first light engine 3. The cover 8 faces the first part 2a of the lampshade 2.

[0049] The distance between the plurality of LEDs 5 and the cover 8 may be between 1 and 5 cm to prevent light spots when the lighting device 1 is turned on.

[0050] A light mixing chamber 10 is formed between the base 4, the two opposing side walls 7 and the cover 8. The light mixing chamber 10 is shaped in a spiral or coiled form having, for example, three or more loops or windings.

[0051] The lampshade 2 may have a conical or cylindrical shape to accommodate the housing against the inner surface of the lampshade 2. The lampshade 2 may be formed by a continuous wall that closes the housing.

[0052] The housing may have a polygonal cross section, such as a rectangular cross section or a square cross section, or may have a cross section of any shape suitable for arranging the carrier 6 on the base 4. Figure 2 In the example of FIG. 4 , the side wall 7 extends from the base 4 to form a frustoconical shape, wherein the carrier 6 is located at the smaller base of the frustoconical shape.

[0053] The carrier 6 is configured to mechanically and / or electrically support the plurality of LEDs 5. The carrier 6 may be a printed circuit board (PCB). The carrier 6 may be transmissive and / or reflective. Furthermore, the carrier may be flexible and, for example, may include a foil made of a polymer such as polyimide (PI) or polyethylene terephthalate (PET). The carrier 6 may include one or more thermally conductive layers and one or more insulating layers. The carrier 6 may be attached to the two opposing side walls 7 using adhesive and / or mechanical fasteners.

[0054] The carrier 6 may be at least partially arranged on the base 4 outside the housing, while the first light source as a whole is still at least partially arranged inside the housing and is arranged to emit light towards the light exit window 11 .

[0055] like Figure 5 As shown, the base 4 may be provided with a plurality of holes 9 to accommodate the LEDs 5 of the light source, such that the LEDs 5 protrude through the holes 9 into the housing.

[0056] Regarding the optical properties of the lampshade and housing, there are various options available for changing the light effects visible through the lampshade.

[0057] The cover and the two opposing side walls may have the same optical properties. For example, the side walls and the cover may be transparent. Alternatively, the side walls and the cover may be light diffusing.

[0058] The cover and the two opposing side walls may also have different optical properties.

[0059] In one embodiment, the cover is a diffuser having a reflectivity less than that of the sidewalls. For example, the cover has a first reflectivity R1 and the sidewalls have a second reflectivity R2, wherein the second reflectivity R2 is at least 20% greater than the first reflectivity R1, or in other words, R2>R1+20%.

[0060] In a second variant, the cover is a diffuser having a higher reflectivity than the sidewalls, for example, the cover has a first reflectivity R1 and the sidewalls have a second reflectivity R2, wherein the second reflectivity R2 is at least 20% less than the first reflectivity R1, or in other words, R2 < R1 - 20%.

[0061] In a third variant, the cover is a diffuser and the two opposing side walls are transparent.

[0062] Regardless of the optical properties of the sidewall, the cover can be transparent. The cover is either part of the lampshade (in which case it is the first part of the lampshade) or part of the housing (in which case it faces the first part of the lampshade). In the former case, the first part (and therefore the cover) can be transparent. In the latter case, both the cover and the first part can be transparent.

[0063] Adjacent to the first portion (which either constitutes the cover or faces the cover), the lamp cover may comprise a second portion separate from the first portion, wherein the first and second portions of the lamp cover have different optical properties.

[0064] The first portion of the lampshade (which is either the cover or the portion of the lampshade facing the cover) and the second portion of the lampshade may have different optical properties.

[0065] The first portion of the lampshade may be transparent and the second portion of the lampshade may be light diffusing. Alternatively, the first portion of the lampshade may be light diffusing and the second portion of the lampshade may be transparent.

[0066] The optical properties of the cover and / or the first part of the lampshade may vary along the coil or spiral of the housing. Additionally or alternatively, the optical properties may also vary in the direction of the longitudinal axis of the lighting device and / or in a direction perpendicular to the longitudinal axis of the lighting device. For example, for at least one ring of the coil or spiral, there may be at least five variations of the optical properties along the ring. The variations may occur gradually or in a step-like manner. The variations may be caused by variations in the thickness of the cover and / or the first part of the lampshade facing the cover (with local increases or decreases to obtain the desired variations). Such variations may also be caused by local variations in the chemical composition of the cover and / or the first part of the lampshade facing the cover.

[0067] The cover body and / or the first part of the lampshade opposite to the cover body may contain reflective particles (such as Ba2SO4, TiO2, Al2O3, SiO2 particles), wherein the aggregation degree and / or type of the particles can be variable along the coiled or spiral shape of the shell, and / or can be variable along a direction parallel to the longitudinal axis of the lighting device, and / or can be variable along a direction perpendicular to the longitudinal axis of the lighting device.

[0068] The lighting device includes a first light source comprising a plurality of first LEDs. Each of the plurality of first LEDs is individually controllable. The lighting device may further include a controller configured to individually control the LEDs in the plurality of first LEDs to vary the intensity and / or color point of the LEDs, thereby achieving a light gradient along a coiled or spiral shape of the light mixing chamber.

[0069] The lighting device may include a second light engine at least partially encapsulated within the housing. The second light engine may also be at least partially encapsulated by the first light engine. The second light engine may include a second light source. The second light source may be an LED light bar. In other words, the second light engine may be an LED light bar.

[0070] At least a portion of the lampshade and the housing can be manufactured by 3D printing.

[0071] The lampshade, housing and cover can be manufactured as separate parts by 3D printing, but they can also be manufactured as a single piece, a whole piece or parts by 3D printing.

[0072] Different 3D printing technologies may be used, such as any one of fused filament fabrication, stereolithography, UV LCD, composite jet printing, multi-jet printing, color jet printing, binder jetting, selective laser sintering, selective laser melting, direct metal laser sintering, electron beam additive manufacturing, multi-jet melting technology, and any combination thereof.

[0073] When fused filament fabrication is selected as the 3D printing technology, the lampshade and at least a portion of the housing may be made of polycarbonate, polyethylene terephthalate, or polyethylene terephthalate glycol, but any other material suitable for use as a printable material in fused filament fabrication may also be used.

[0074] A method for manufacturing a coiled or spiral-shaped housing by fused deposition modeling may include the following steps. First, a computer-aided design (CAD) of a straight housing is prepared. In other words, the housing is designed to be the desired straightened or unfolded coiled or spiral shape. Second, the CAD design of the straightened (or unfolded) housing is sliced using a G-code slicing program to provide process settings and coordinates in XYZ space. Third, the XYZ coordinates are transformed into X-rotated-Z coordinates. Fourth, the housing is printed using the transformed coordinates using a printer with a rotating cylindrical mandrel as a build platform. In the printer, the print head moves along an X-axis gantry that can move up and down along the Z-axis. The Y-axis is replaced by a rotational axis around which the cylindrical mandrel can rotate. This allows the housing designed to be straightened (or unfolded) to be printed in a coiled or spiral shape onto the rotating cylindrical mandrel. Fifth, the coiled or spiral housing can be removed from the cylindrical mandrel for assembly with a lampshade to form a lighting fixture.

Claims

1. A lighting device (1), comprising a lampshade (2) and a first light engine (3) encapsulated in the lampshade (2), wherein the first light engine (3) comprises: a housing having two opposite side walls (7) extending from the base (4) and defining a light exit window (11) arranged opposite to the base (4), and a first light source, comprising a plurality of first LEDs (5), the plurality of first LEDs being arranged on a first carrier (6), the first light source being at least partially disposed within the housing and being arranged to emit light toward the light exit window (11), The lighting device (1) further comprises a light mixing chamber (10), the light mixing chamber being formed between the base (4), the two side walls (7) and the cover (8), the cover extending between the two side walls (7) and enclosing the light exit window (11). The cover (8) is: (i) the first part of the lampshade (2); or (ii) a part of the housing of the first light engine (3), and the cover faces the first part (2a) of the lampshade (2). Wherein, the light mixing chamber (10) has a coiled shape or a spiral shape, The cover (8) and the two side walls (7) have different optical properties. Wherein, the cover (8) is a diffuser having a first reflectivity R1, and Wherein, (i) the two side walls (7) have a second reflectivity R2 and R2 < R1-20%, or (ii) the two side walls (7) are transparent.

2. The lighting device (1) according to claim 1, wherein The first part (2a) of the lampshade (2) is transparent.

3. A lighting device (1) according to any one of the preceding claims, wherein The lampshade (2) comprises a second portion separated from the first portion (2a), wherein the first portion (2a) and the second portion have different optical properties.

4. The lighting device (1) according to claim 3, wherein The first part (2a) of the lampshade (2) is transparent and the second part of the lampshade (2) is light-diffusing, or the first part (2a) of the lampshade (2) is light-diffusing and the second part of the lampshade (2) is transparent.

5. The lighting device (1) according to any one of the preceding claims, wherein The first carrier (6) is at least partially arranged on the base (4) outside the housing.

6. The lighting device (1) according to claim 5, wherein The base (4) is provided with a plurality of holes (9) to accommodate portions of the plurality of first LEDs (5) protruding through the plurality of holes (9).

7. A lighting device (1) according to any one of the preceding claims, wherein The optical properties of at least one of the first portion (2a) of the lampshade (2) and the cover (8): (i) change along the coiled or spiral shape of the light mixing chamber (10); and / or (ii) change along a direction parallel to the longitudinal axis of the lighting device (1); and / or (iii) change along a direction perpendicular to the longitudinal axis of the lighting device (1).

8. The lighting device (1) according to claim 7, wherein The light mixing chamber (10) comprises at least three rings, wherein at least one ring has N optical property changes, and wherein N is at least 5.

9. The lighting device (1) according to any one of claims 7 and 8, wherein In order to obtain the varied optical properties, at least one of the portion (2a) of the lampshade (2) and the cover (8): (i) has a locally reduced or increased thickness; and / or (ii) contains reflective particles, wherein the concentration and / or type of the reflective particles varies locally.

10. The lighting device (1) according to any one of the preceding claims, wherein The first light source includes an LED light bar or an LED light belt.

11. The lighting device (1) according to any one of the preceding claims, wherein Each of the plurality of first LEDs (5) is individually controllable, and wherein the lighting device (1) comprises a controller for individually controlling the LEDs of the plurality of first LEDs (5) to vary the intensity and / or color point of the LEDs, thereby obtaining a light gradient along the coiled or spiral shape of the light mixing chamber (10).

12. The lighting device (1) according to any one of the preceding claims, wherein The lighting device (1) further comprises a second light engine at least partially encapsulated within the first light engine (3).

13. The lighting device (1) according to any one of the preceding claims, wherein The lampshade (2) and at least a portion of the housing are manufactured by 3D printing.

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