Light emitting device

Abstract

A light emitting device (1) adapted to project a light beam (15) onto a target surface, the light emitting device (1) comprising: a light engine (2) comprising a light source (3); a light mixing chamber (4); and an optical component (5) having a spherical shape with a curved light receiving surface (51). The light source (3) is arranged to emit light towards a light exit window (41) of at least one light mixing chamber in operation, the light exit window (41) of at least one light mixing chamber (4) thereby acting as an extended light source with a curved light emitting surface, the optical component (5) being arranged adjacent to the light exit window (41) of the light mixing chamber, and the curved light emitting surface of at least one light mixing chamber (4) being conformal to the curved light receiving surface (51) of the optical component (5) and coinciding with a focal surface (52) of the optical component (5).

Description

Technical Field

[0001] The invention relates to a lighting device adapted to project a light beam onto a target surface, the lighting device comprising at least one light engine comprising at least one light source adapted to emit light in operation, at least one light mixing chamber and an optical assembly.

[0002] As used herein, a light mixing chamber is intended to mean a chamber, cavity, tube, box, or the like, which is suitable for or capable of mixing light originating from one or more light sources and propagating therethrough to form an output that is a mixture of light from the one or more light sources. Background Art

[0003] There is a rapidly increasing interest in dynamic LED lighting systems, where the beam changes its shape depending on the user's needs. The beam can be controlled by a smartphone or remote control. Current examples of beam control use liquid crystal (LC) elements to control the shape of a collimated LED beam. Other examples have small built-in motors to control the movement of optical components within the fixture. Dynamic beams are also possible by using pixelated LED light sources. These configurations work very well, but require multiple optical components (such as a condenser lens, multiple plano-convex lenses, and a diffuser film) to shape the final beam.

[0004] For example, prior art document US-4727457 discloses a device with a spherical lens and an LED. The LED can be located in the focus of the spherical lens, or within the focal length. However, the device is an omnidirectional light source for decorative lighting and is not capable of projecting a clear image.

[0005] Additionally, all known concepts for remotely adjusting a light beam are either expensive or require a great deal of effort to construct and maintain over a considerable lifetime (eg, more than 50,000 hours).

[0006] It would therefore be desirable to provide a lighting device of the type mentioned by way of introduction which has a simpler construction, is inexpensive, is easy to construct and which requires little or no maintenance during its lifetime. Summary of the invention

[0007] The object of the present invention is to overcome this problem and to provide a lighting device suitable for projecting a light beam onto a target surface, which lighting device has a simpler construction, is cheap, is easy to construct and which lighting device requires little or no maintenance during its lifetime.

[0008] According to a first aspect of the invention, this and other objects are achieved by means of a light emitting device adapted to project a light beam onto a target surface, the light emitting device comprising: a light engine comprising a light source; a light mixing chamber; and an optical assembly having a spherical shape with a curved light receiving surface. The light source is arranged to emit light towards a light exit window of the light mixing chamber in operation, the light exit window of the light mixing chamber thereby acting as an extended light source with a curved light emitting surface, the optical assembly being arranged adjacent to the light exit window of the light mixing chamber, and the curved light emitting surface of the light mixing chamber is conformal to the curved light receiving surface of the optical assembly and coincides with a focal surface of the optical assembly.

[0009] Thus, a lighting device is provided which makes it possible to provide an adjustable light beam using a single optical component, namely a spherical optical component, combined with a shaped extended light source (due to the provision of at least one light mixing chamber). Such a lighting device has a very simple construction, requires few components and is cheap to manufacture.

[0010] In particular, by arranging the curved light emitting surface of the light mixing chamber to conform to the curved light receiving surface of the optical assembly and further coincide with the focal surface of the optical assembly, a light emitting device is provided which is particularly simple to construct and assemble and which requires little or no maintenance during its lifetime. Such a light emitting device is capable of projecting very clear images.

[0011] Furthermore, as will become clear from below, because the extended light source can be divided into pixels or domains, patterned (dynamic) lighting becomes possible. This approach has great potential for retail / store lighting, architectural lighting and outdoor lighting.

[0012] In an embodiment, the optical component is a ball lens, a spherical lens, or a dielectric sphere.

[0013] Such an optical assembly is very useful for lighting purposes and provides not only a particularly simple construction of the light-emitting device but also a particularly sharp projected image.

[0014] In an embodiment, the light source includes any one of at least one LED, an LED array, a mini-LED array, and a micro-LED array.

[0015] Such a light emitting device is particularly simple to construct. Furthermore, providing an array of LEDs, mini-LEDs and micro-LEDs provides a particularly uniform light output of the extended light source and thus of the light beam exiting the light mixing chamber.

[0016] In an embodiment, each LED in an array of LEDs, mini-LEDs and / or micro-LEDs is individually controllable.

[0017] In addition to the above, this provides the ability to fine tune the light output of the extended light source and thus the light beam exiting the light mixing chamber.

[0018] In an embodiment, the light emitting device comprises two or more light engines.

[0019] Hereby, a lighting device is provided which has greater versatility with respect to the variation of the achievable light output and which can therefore satisfy a wider range of user requirements.

[0020] In an embodiment, the light exit window of the light mixing chamber is rectangular.

[0021] Hereby, a lighting device is provided which allows providing more complex and customizable lighting patterns, especially in combination with employing more than one light source.

[0022] In an embodiment, the light mixing chamber comprises reflective walls.

[0023] Thereby, a lighting device is provided which minimizes or completely avoids light losses in the light mixing chamber and with which the light output of the light mixing chamber is particularly uniform.

[0024] In an embodiment, a diffuser is arranged at the light exit window of the light mixing chamber.

[0025] Thereby, a lighting device is provided with which the light transmitted to the optical component is particularly homogeneous and furthermore free from artefacts.

[0026] In an embodiment, the shape of the diffuser is conformal to the shape of the optical component.

[0027] Thereby, a lighting device is provided which is of particularly simple construction and which requires little or no maintenance during its service life. Furthermore, such a lighting device is able to project particularly sharp images.

[0028] In an embodiment, the light mixing chamber is divided into at least two compartments.

[0029] Hereby, a lighting device is provided which has greater versatility with respect to the possible lighting patterns that can be obtained and which can therefore satisfy a wider range of user requirements.

[0030] In an embodiment, at least two compartments of the light mixing chamber are separated by means of a diffusely reflecting wall or a specularly reflecting wall.

[0031] Thus, a lighting device is provided which enables the light output of each compartment of a light mixing chamber to be individually controlled and which therefore has great versatility with respect to the variation of the light output that can be obtained. Furthermore, by arranging the partition walls as reflective or mirrored walls, a lighting device is provided which minimizes or completely avoids light losses at the partition walls and with which the light output of the light mixing chamber is thus particularly uniform.

[0032] In an embodiment, the light mixing chamber comprises any one of a mixing rod, a tapered mixing rod, a light guide, a tapered light guide, a tapered hexagonal collimator, and a square mixing rod array.

[0033] Thereby, a lighting device is provided which has a particularly great versatility with regard to the possible illumination patterns which can be obtained, since in principle any illumination pattern can be obtained depending on the specific configuration and distribution of the components of the light mixing chamber.

[0034] Furthermore, the optical efficiency of the light emitting device is improved by collimating the light output of the light mixing chamber.

[0035] In an embodiment, the optical component is or comprises a lens array.

[0036] This embodiment is particularly advantageous for spotlight modules and provides a further increased versatility with regard to the possible lighting patterns.

[0037] In an embodiment, each lens in the lens array is associated with a light source.

[0038] Thereby, a light emitting device is provided which has a reduced thickness and which has excellent thermal properties.

[0039] Furthermore, in a second aspect, the invention relates to a lamp, a luminaire, or a lighting device comprising the light emitting device according to the invention.

[0040] Such a lamp, luminaire or lighting device may be a lamp, luminaire or lighting device for retail or store lighting, for architectural lighting or for outdoor lighting purposes, such as a spotlight module.

[0041] It is noted that the invention relates to all possible combinations of features recited in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] This and other aspects of the present invention will now be described in more detail, with reference to the accompanying drawings showing embodiment(s) of the invention.

[0043] Figure 1 A schematic cross-sectional side view of a first embodiment of a light emitting device according to the invention is shown.

[0044] Figure 2A A cross-sectional side view of a second embodiment of a light emitting device according to the invention is shown.

[0045] Figure 2B Shown according to Figure 2A Bottom view of a light emitting device.

[0046] Figure 2C Shown according to Figure 2A Perspective view of a light mixing chamber of a light emitting device.

[0047] Figure 3A The diagram shows the use of Figure 2A The light pattern obtained by the light emitting device, and Figure 3B The diagram shows the use of Figure 2A The intensity distribution obtained by the light-emitting device.

[0048] Figure 4A A cross-sectional side view of a third embodiment of a light emitting device according to the invention is shown.

[0049] Figure 4B Shown according to Figure 4A Bottom view of a light emitting device.

[0050] Figure 4C Shown according to Figure 4A Perspective view of a light mixing chamber of a light emitting device.

[0051] Figure 5A The diagram shows the use of Figure 4A The light pattern obtained by the light emitting device, and Figure 5B The diagram shows the use of Figure 4A The intensity distribution obtained by the light-emitting device.

[0052] Fig. 6A A cross-sectional side view of a fourth embodiment of a light emitting device according to the invention is shown and comprises two light sources adapted to emit light having mutually different color temperatures.

[0053] Figure 6B Shown according to Fig. 6A A cross-sectional side view from another perspective of the light emitting device.

[0054] Figure 6C Shown according to Fig. 6A Bottom view of a light emitting device.

[0055] Figure 7A-7C The diagram shows the use of Fig. 6A Three different exemplary light patterns (top) and intensity distributions (bottom) that can be obtained with a light emitting device. Fig. 7A The figure shows the result when both light sources are turned on. Figure 7Bshows the result of turning on a light source with a higher color temperature, and Figure 7C The result is shown with the light source having a lower color temperature turned on.

[0056] Fig. 8A A schematic cross-sectional side view of a fifth embodiment of a light emitting device according to the invention is shown and comprises a light mixing chamber having two compartments.

[0057] Figure 8B Shown according to Fig. 8A Perspective View Of A Lighting Device.

[0058] Fig. 9A and Fig. 9B The diagram shows the use of Fig. 8A Two different exemplary intensity distributions that can be obtained with a light emitting device. Fig. 9A The figure shows the result of turning on the light sources arranged in two compartments, while Fig. 9B The result is shown when a light source arranged in one compartment is turned on and a light source arranged in another compartment is turned off.

[0059] Fig.10 A perspective view showing a sixth embodiment of a light emitting device according to the present invention is shown.

[0060] Fig.11A A perspective view showing a seventh embodiment of a light emitting device according to the present invention is shown.

[0061] Fig. 11B Shown according to Fig.11A Cross-sectional side view of a light emitting device.

[0062] Fig. 12A and Fig. 12B The diagram shows the use of Fig.11A Two different exemplary light patterns that can be obtained by the light emitting device.

[0063] Fig.13 A cross-sectional side view of an eighth embodiment of a light emitting device according to the present invention is shown and comprises a plurality of light engines.

[0064] Like reference numerals refer to like elements throughout.

[0065] Note that throughout the drawings, see e.g. Figure 3A , represents the illuminance on a projection surface (e.g. a floor or a wall) and see e.g. Figure 3B , The far-field intensity profile obtained using the light emitting device is shown. DETAILED DESCRIPTION

[0066] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the present invention are shown. However, the present invention may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; on the contrary, these embodiments are provided for thoroughness and completeness and to fully convey the scope of the present invention to the skilled person.

[0067] Figure 1 A cross-sectional side view of a light emitting device 1 according to a first embodiment of the present invention is shown.

[0068] Typically, and independently of the embodiment, the lighting device 1 is of a type suitable for projecting a light beam 15 onto a target surface. The lighting device 1 comprises at least one light engine 2. The light engine 2 comprises one or more light sources 3, at least one light mixing chamber 4 and an optical assembly 5. The optical assembly 5 has a spherical shape.

[0069] Generally, and independently of the embodiment, the at least one light mixing chamber 4 is arranged between the at least one light source 3 and the spherical optical component 5 when seen along the optical axis 6 of the light emitting device 1 .

[0070] Furthermore, the light emitting device may comprise a housing 7 having a front window 8. The housing 7 may be a black absorbing housing or tube. The front window 8 is transparent and may be made, for example, of transparent polycarbonate or textured PMMA, optionally provided with a diffusing component such as a diffuser film.

[0071] Typically, and regardless of the embodiment, at least one light source 3 comprises one or more LEDs. The LEDs may be adapted to emit light of any feasible color. In embodiments comprising two or more LEDs, the LEDs may be adapted to emit light of the same color temperature or of two or more different color temperatures. At least one LED may also be an adjustable LED.

[0072] Typically, and independently of the embodiment, at least one light mixing chamber comprises a light exit surface or window 41, a bottom surface 43, and a peripheral surface 42 extending between the light exit window 41 and the bottom surface 43. The bottom surface 43 and the peripheral surface 42 are non-luminous surfaces.

[0073] Figure 1 The lighting device 1 comprises a light mixing chamber 4 and a light source 3. At least one light source 3 is arranged on a bottom surface 43 of the light mixing chamber.

[0074] Typically, and independently of the embodiment, the at least one light source 3 is arranged to emit light in operation in a direction generally towards the light exit window 41 of the light mixing chamber 4 so that the light exit window 41 of the light mixing chamber 4 thereby acts as an extended light source.

[0075] Typically, and regardless of the embodiment, the optical component 5 is arranged adjacent to the light exit window 41 of the light mixing chamber 4. The light exit window 41 of the light mixing chamber comprises a curved surface configured to conform to the curvature of the outer surface 51 of the optical component 5. See also FIG. 5 for better illustrating the curvature of the light exit window 41. Figure 2C and Figure 4C Furthermore, the light exit window 41 is positioned so as to coincide with the focal surface 52 of the optical component 5 .

[0076] like Figure 1 As schematically shown in FIG. 1 , the optical component 5 may be a dielectric sphere, a spherical lens or a spherical lens. Such an optical component is characterized by having a radius and refractive index The optical assembly 5 also includes a diameter . Figure 1 shows the focus of a parallel incident beam .focus is located on the focal plane 52. The focal plane 52 is a spherical surface. Therefore, the focal length Satisfaction relationship:

[0077] {1}.

[0078] The focal plane (or focal surface) of a spherical lens is usually located close to the spherical lens surface. For example, if the refractive index If the focal plane is exactly on the surface of the spherical lens, the focal plane is 2. This type of lens is usually used for fiber-to-fiber coupling.

[0079] Spherical lenses and ball-shaped lenses are very useful for lighting applications. Since the focal plane is very close to the spherical lens surface, it is possible to project the image of the extended light source on the floor or wall in an effective way. A prerequisite is that the surface of the extended light source, and therefore the surface of the light exit window 41 of the light mixing chamber 4 in the present invention, follows the shape of the focal plane 52.

[0080] Figure 2A A cross-sectional side view of a light emitting device 100 according to a second embodiment of the present invention is shown. Figure 2B Shown according to Figure 2A A bottom view of the light emitting device 100, and Figure 2C Shown according to Figure 2A 100 is a perspective view of a light mixing chamber of a light emitting device 100. The light emitting device 100 is similar to the light emitting device 100 described above. Figure 1 The light emitting device of FIG. 10 is different in that the light mixing chamber 400 of the light emitting device 100 is provided with a square cross-sectional shape.

[0081] The reason for providing the light mixing chamber 400 of the light emitting device 100 with a square cross-sectional shape is to provide a square lighting pattern. Figure 3AAs illustrated, such a light mixing chamber 400 effectively provides a square light pattern with concave sides. Figure 3B Pictured Figure 3A The intensity distribution of the pattern.

[0082] Figure 4A A cross-sectional side view of a light emitting device 101 according to a third embodiment of the present invention is shown. Figure 4B Shown according to Figure 4A A bottom view of the light emitting device 101, and Figure 4C Shown according to Figure 4A A perspective view of the light mixing chamber 401 of the light emitting device 101. The light emitting device 101 is similar to the light mixing chamber 401 described above. Figure 1-2C The light emitting device of FIG. 1 is different in that the light mixing chamber 401 of the light emitting device 101 is provided with a square cross-sectional shape having concave sides. Since the concave sides are provided in order to obtain a perfect square illumination pattern, the shape of the light exit window 41 should be the same as that of FIG. Figure 2A-2C The perimeter shape of the light exit window 41 of the light mixing chamber 401 can be defined by the following parametric equation:

[0083]

[0084] In Equation 2 and Equation 3, is a parameter describing the perimeter of the mixing chamber The parameters in is the scaling factor, and is the factor that determines the shape. For example, in Equation 2 and Equation 3, is equal to 10 mm and = 1.22. In the embodiment shown, Equal to 15 mm, is equal to 2.00, is equal to 15 mm, and =15.1 mm. The resulting illuminance on the projection surface (e.g. floor or wall) is Figure 5A , which is characterized by a perfect square pattern, and the far-field intensity curve obtained using the light emitting device 401 is shown in FIG. Figure 5B In the examples illustrated in Fig. 3 and Fig. 5 respectively, the distance between the light exit window 41 and the projection is 2000 mm.

[0085] In the above embodiment, it is assumed that the extended light source is completely uniform, that is, the light emittance (lm / m 2 ) is constant over the entire light emitting area. In order to adjust the projected illumination (eg to produce a perfectly evenly illuminated square), the light emittance of the extended light source can be adapted.

[0086] Another aspect is the quality or uniformity of the extended light source. This aspect can be taken into account by arranging the light source 3 as a dense array of mini-LEDs or micro-LEDs. Typical mini-LEDs have a size of 100-200 microns. Micro-LEDs are much smaller, such as 10-50 microns. These LEDs form an almost continuous emitting surface. In the projected image, the individual LEDs are barely visible. In this particular case, the micro-LEDs form an almost continuous emitting area. However, there are still small slits or gaps between the LEDs, which can be seen when fully imaged. In order to avoid imaging of these slits or gaps, and thus fine-tune the uniformity of the projected light pattern, the entire collection of micro-LEDs can be placed slightly (such as + / - 0.2 mm) out of focus, i.e. a little in front of or behind the focal plane. In order to fine-tune the uniformity of the projected light pattern, the light source can be placed slightly out of focus (e.g. in front of or behind the focal plane).

[0087] Now go to Fig. 6A , shows a cross-sectional side view of a light emitting device 102 according to a fourth embodiment of the present invention. Figure 6B Shows another perspective on Fig. 6A A cross-sectional side view of the light emitting device 102, and Figure 6C Shown according to Fig. 6A The light emitting device 102 is different from the light emitting device described above in that two light sources 31 and 32 and two light mixing chambers 402 and 402' are provided (see Figure 6B ). The two light sources 31, 32 are arranged on rectangular light mixing chambers 402, 402' arranged adjacent to each other. The light exit windows 41 of the two light mixing chambers 402, 402' comprise a curvature that is consistent with the curvature of the surface 51 of the optical component 5. In the example shown, this arrangement is combined with a spherical lens 5, wherein Equal to 15 mm, is equal to 1.80, is equal to 16.9 mm, and The two adjacently arranged light sources 31 and 32 and therefore also the two rectangular light exit windows 41 of the light mixing chamber 402 , 402 ′ emit light having different color temperatures, such as 2200 K and 6500 K, for example.

[0088] The two rectangular light exit windows 41 of the light mixing chambers 402, 402' generate three possible lighting configurations, such as Fig. 7A (Light sources 31 and 32 are both turned on), Figure 7B (only light source 32 is on) and Figure 7C(only light source 31 is on). The distance from the light emitting device to the projection surface is 2000 mm. This embodiment allows for more complex and customizable lighting patterns.

[0089] Fig. 8A A cross-sectional side view of a light emitting device 103 according to a fifth embodiment of the present invention is shown. Figure 8B Shown according to Fig. 8A 103 is a perspective view of a light mixing chamber 403 of a light emitting device 103. The light emitting device 103 differs from the light emitting devices described above in that the light mixing chamber 403 is provided with two compartments 9 and 10 separated by an optical partition sheet or an optical partition wall 11. Embodiments with more than two such compartments are also feasible. Thus, a more complex and flexible system can be designed using a freeform mixing chamber, which consists of a large number of compartments that can be controlled individually. The light source 3 is placed on a flat surface 43 of the light mixing chamber 403. In this embodiment, the light mixing chamber 403 can in particular be a light mixing box. Furthermore, the light mixing chamber 403 comprises a highly reflective and optionally also diffusive wall 42. The diffuser 12 ( Fig. 8A ) is placed at the light exit window 41 of the light mixing chamber 403. The diffuser 12 is shaped to follow the shape of the focal surface of the spherical optical component 5. The advantage of such a light mixing chamber 403 is that the spherical optical component 5 receives uniform light from the various light sources 3 without any artifacts.

[0090] By changing the height of the light mixing chamber 403 and / or the arrangement of the light source 3 on the flat bottom surface 43 to adjust the light emittance (lm / m 2 ). This applies in principle to all embodiments disclosed herein.

[0091] In addition, the diffuser 12 may have different diffusion properties depending on the corresponding position on the light exit window 41 of the light mixing chamber 403. For example, when a volume diffuser is used, the thickness of the diffuser 12 may vary over the light exit window 41. Fig. 8A and Figure 8B In the example, the height of the mixing chamber is 10 mm, and the diameter is 24 mm. For spherical optical components, Equal to 15 mm, is equal to 2.0, and Equal to 15.1 mm. Ten light sources 3 are provided, each of which has a size of 1 mm by 1 mm. These light sources 3 are placed on a circle with a radius of 10 mm on the bottom 43 of the light mixing chamber 403. The light sources 3 are LEDs with a Lambertian emission curve.

[0092] Fig. 9A The diagram shows Figure 8A-B The beam shape (far-field intensity curve) obtained when the light sources in the two compartments 9 and 10 of the light mixing chamber 403 of the light emitting device 103 are turned on, and Fig. 9B The beam shape obtained when only the light source in one compartment is turned on (far field intensity graph) is shown. The illuminance on the projected area is also Fig. 9A and Fig. 9B The projection area is 6000 mm by 6000 mm and the distance to the projection area is 2000 mm.

[0093] Note that the dividers between compartments can be either rigid or flexible. Fig. 8A and Figure 8B A hard division between the compartments is shown. The transition can be made softer or more gradual by using a divider or wall of lower height (ie not contacting the shaped diffuser over its entire length).

[0094] Fig.10 A perspective view of a light emitting device 104 according to a sixth embodiment of the invention is shown. The light emitting device 104 differs from the light emitting devices described above in that the light mixing chamber is provided with a tapered configuration. More specifically, the light mixing chamber 404 is a tapered hexagonal collimator for mixing and collimating light from two LED light sources 31, 32 having mutually different color temperatures (e.g. 2200 K and 6500 K). The advantage of collimated light (in addition to mixing the colors of two different LED light sources) is that a higher optical efficiency and the formation of a clearer (sharper) image are obtained.

[0095] Fig.11A A perspective view of a light emitting device 105 according to a seventh embodiment of the present invention is shown. Fig. 11B Shown according to Fig.11A sectional side view of a light emitting device 105. The light emitting device 105 differs from the light emitting devices described above in that the light mixing chamber 405 comprises an array of mixing rods 13, 13' having a square cross-sectional shape. In the example shown, an array of 5 by 5 - or a total of 25 - mixing rods 13, 13' is provided. Different array sizes are also feasible. The 25 light exit windows 41 thus formed are shaped so that in combination they correspond to the shape of the focal surface of the spherical optical component 5. Each mixing rod 13, 13' is associated with one or more LED light sources 3. Each LED light source 3 or LED light source cluster is suitable for being individually controlled, i.e. turned on or off or even dimmed. With the aid of such a light emitting device 105, complex light patterns can be generated, such as Fig. 12A and Fig. 12B As shown in the figure. Fig. 12A shows the result when all light sources 3 are turned on, and Fig. 12BThe result is shown where some light sources 3 are switched on and others are switched off.

[0096] Fig.13 FIG. 1 shows a cross-sectional side view of a light emitting device 106 according to an eighth embodiment of the present invention. The light emitting device 106 is similar to the light emitting devices described above (and in particular with respect to FIG. 1 ). Figure 1 The light emitting device described in the foregoing description differs in that an array of spherical optical components 5 is provided, each spherical optical component 5 being associated with a light mixing chamber 4 and one or more light sources. For simplicity, Fig.13 In other words, the light emitting device 106 comprises a plurality of light engines 2, in particular five light engines 2 as shown by way of non-limiting example.

[0097] Those skilled in the art realize that the present invention is by no means limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0098] Moreover, variations to the disclosed embodiments may be understood and effected by those skilled in the art in practicing the claimed invention, by studying the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. 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.

Claims

1. A light emitting device (1) adapted to project a light beam (15) onto a target surface, the light emitting device (1) comprising: A light engine (2) comprising a light source (3), The light mixing chamber (4) comprises a light exit window (41), an optical component (5) having a spherical shape with a curved light receiving surface (51), and Diffuser (12), wherein the light source (3) is arranged to emit light towards a light exit window (41) of the light mixing chamber in operation, The diffuser (12) is arranged at the light exit window (41) of the light mixing chamber (4), wherein the optical component (5) is arranged adjacent to the diffuser (12), wherein the shape of the diffuser (12) is conformal to the curved light receiving surface (51) of the optical component (5), and wherein the diffuser is arranged to be spaced a certain distance from the optical component and coincide with the focal surface of the optical component, wherein the optical component is configured to satisfy the following relationship: f = RRn / (2(n-1)) Where f is the focal length of the optical component, R is the radius of the optical component, and n is the refractive index of the optical component.

2. The light emitting device according to claim 1, wherein the optical component (5) is a spherical lens or a dielectric sphere.

3. The light emitting device according to claim 1, wherein the light source (3) comprises any one of a mini-LED array and a micro-LED array.

4. A light emitting device according to claim 3, wherein each LED in the array of mini-LEDs and / or micro-LEDs is individually controllable.

5. A lighting device according to any one of the preceding claims 1 to 4, and comprising two or more light engines (2).

6. A lighting device according to any one of the preceding claims 1 to 4, wherein the light exit window (41) of the light mixing chamber is rectangular.

7. A lighting device according to any of the preceding claims 1 to 4, wherein the light mixing chamber (4) comprises a reflecting wall (42; 43).

8. A lighting device according to any of the preceding claims 1 to 4, wherein the light mixing chamber (4) is divided into at least two compartments (9, 10).

9. Lighting device according to claim 8, wherein at least two compartments (9, 10) of the light mixing chamber are separated by means of a diffusely reflecting wall or a specularly reflecting wall (11).

10. The lighting device according to any one of the above claims 1-4, wherein the light mixing chamber (4) comprises any one of a mixing rod and a light guide.

11. The lighting device according to any one of the preceding claims 1 to 4, wherein the optical component (5) is a lens array or comprises a lens array.

12. Light emitting device according to claim 11, wherein each lens of the lens array is associated with a light source (3).

13. The light emitting device according to any one of the preceding claims 1-4, wherein the light mixing chamber (4) comprises any one of a tapered mixing rod, a tapered light guide, a tapered hexagonal collimator, and a square mixing rod array.

14. Light emitting device according to claim 1, wherein the light source (3) comprises at least one LED.

15. Light emitting device according to claim 1, wherein the light source (3) comprises an LED array.

16. The light emitting device of claim 15, wherein each LED in the LED array is individually controllable.

17. A luminaire comprising a light emitting device according to any one of the preceding claims.

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