Energy saving illumination device simulating natural light

Abstract

The present invention refers in general terms to an illumination device for simulating natural illumination, thus capable of generating at least two light components with different angular distributions having different correlated color temperature or CCT. In particular, the present invention is directed to an illumination device (10,50) for simulating natural illumination com prising: a first optical unit (20) comprising a primary light source (21) comprising a diffusion chamber (14) within which ends at least one emission termination (15 A) of an optical fiber (15) configured to be connected upstream to a natural light source, such as a sunlight collection unit (40), and / or an artificial light source, the primary light source (21) being configured to emit a primary light (22) in the visible spectrum and with a primary light correlated color temperature (CCTp), and a dichroic separating optic (23) configured to intercept at least part of the primary light (22) generated by the primary light source (21) and emit, from a first emitting surface (25), at least one strongly collimated first light component (24a) having a propagation direction (A), generated starting from the primary light (22), and at least one diffuse light component (24b), the at least one first strongly collimated light component (24a) and the at least one diffuse light component (24b) forming a light with chromatic components with different angular distributions (24), wherein the light with chromatic components with different angular distributions (24) has a total flux and a light intensity profile characterized by a first angular aperture (a) less than 40° measured as half-width at half-maximum (HWHM) with reference to at least one semi section plane (X) of the dichroic separating optic (23) containing the propagation direction (A), and wherein, when the primary light correlated color temperature (CCTP) is substantially equal to or higher than 5000 K, the light with chromatic components with different angular distributions (24) has a greater correlated color sum temperature (CCTS) when measured at at least one measurement angle higher than 1.5 times the first angular aperture (a) than when measured at an angle of 0° with respect to the propagation direction (A); and a second optical unit (30) comprising a secondary collimating optic (33) configured to receive as input at least part of the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25) and emit as output, starting from this light with chromatic components with different angular distributions (24), a weakly collimated light component (34b) and a second strongly collimated light component (34a) forming a collimated light (34) with chromatic components with different angular distributions emitted from the second optical unit (30), wherein the secondary collimating optic (33) is configured to intercept at least the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25) at angles higher than a cut-off angle (T), measured with respect to the propagation direction (A), wherein the cut-off angle (T) is less than 85°, preferably less than 80°, more pref¬ erably less than 75°; and wherein the collimated light (34) with chromatic components with different angular distributions emitted by the optic secondary collimation (33) has substantially the same luminous flux, integrated over an angular range of angles between 0° and the first angular aperture (a), with respect to a luminous flux of the light with chromatic components with different angular distributions (24) integrated over the same angular range and / or a second angular aperture (a') of the light intensity profile substantially equal to or less than the first angular aperture (a) of the light intensity profile of the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25).

Description

ENERGY SAVING ILLUMINATION DEVICESIMULATING NATURAL LIGHTTechnical field[1] The present invention refers in general terms to an energy-saving illumination device for simulating natural illumination, specifically for simulating the light of the sky and the sun, thus capable of generating at least two artificial light components with different angular distributions and having different correlated color temperature or CCT. In particular, the present invention refers to an illumination device capable of generating, starting from natural light, a first strongly collimated artificial light component having a CCT lower than the CCT of a second weakly collimated artificial light component, i.e. having an angular aperture of the intensity profile greater than the angular aperture of the strongly collimated light component.State of the art[2] In the state of the art illumination devices are known to simulate natural illumination, specifically sky and sun light, capable of generating light with chromatic components with different angular distributions, with a first directional light component, or direct light, having a first correlated color temperature or lower CCT, and a second diffuse light component having a second greater CCT.[3] Exemplary embodiments of such illumination devices may use, for example, Rayleigh -type diffusion layers as described in several patent applications of the same Applicant such as for example WO 2009 / 156347 Al, WO 2009 / 156348 Al, WO 2014 / 076656 Al, and WO 2017 / 0847561 AL Known illumination devices mostly use a light source that produces light in the visible, and a panel containing nanoparticles. The panel is illuminated by the light source and acts as a so-called chromatic diffuser or Rayleigh-like diffuser, i.e. it diffuses the incident light in a manner similar to the earth’s atmosphere under clear sky conditions, thus separating the incident light into a first component of direct light that crosses the panel substantially without being diffused and a second component of light diffused by the panel. In particular, the diffuse light component has a greater CCT than the direct light component, as the Rayleigh-like diffuser has a diffusion element efficiency that is a function of the wavelength of the light and is greater for shorter wavelengths.[4] Also known are artificial sunlight component generating units for illumination devices for simulating natural light that operate starting from sunlight itself, as described in International Patent Application No. WO 2018 / 157902 of the same Applicant. Such units are configured to realize, starting from sunlight, an extended substantially collimated light emitting surface which, in combination with a diffuse light generating unit with higher CCT, allows to generate light with chromatic components with different angular distributions, with a first directional light component, or direct light, having a first correlated color temperature or lower CCT, and a second diffuse light component having a second greater CCT.[5] Thanks to the interaction between the direct component with lower CCT that illuminates the objects and projects their shadows, and the diffuse light with higher CCT, which gives the shadows a bluish coloring, the illumination systems are able to faithfully recreate the illumination produced naturally by sun and sky, thus giving the environment a perception of large space.[6] From International Patent Application No. WO 2022 / 023868 of the same Applicant, so-called secondary illumination devices are also known, i.e. used in combination with primary illumination devices for simulating natural illumination, in order to achieve a higher degree of illumination than that provided by the primary natural illumination device alone, while keeping the costs of the overall system used to illuminate the environment low. In particular, the secondary illumination devices described in WO 2022 / 023868 are themselves capable of generating light with chromatic components with different angular distributions with chromatic characteristics and angular aperture of the intensity profile that are comparable to the light components generated by the primary illumination device simulating natural illumination.[7] These secondary illumination devices are particularly effective in achieving a sufficient degree of illumination in the environment without altering the perception offered by the primary illumination devices and without excessively increasing the overall costs of the system. However, such secondary illumination devices are correlated to a significant increase in the overall energy consumption of the entire system.[8] In light of the above, the Applicant has set himself the purpose of devising an illumination device for simulating natural illumination that can be used as a secondary illumination device in association with primary illumination devices simulating natural illumination and that at the same time allows to improve the overall energy efficiency of the entire system consisting of the set of the primary and secondary illumination devices.[9] In particular, the Applicant has set himself the goal of realizing an illumination device for simulating natural illumination that is additionally capable of reproducing natural illuminationwithout presenting glare effects or unnatural colorings of the ceiling of the environment in which it is installed, while offering a high illumination efficiency.

[0010] Finally, the Applicant has set himself the goal of developing an illumination device that can be implemented in the absence of electrical and electronic circuits that can be used without producing interferences in the context of medical -diagnostic nuclear magnetic resonance (MRI) applications.Summary of the invention

[0011] In a first aspect, the present invention is directed to an illumination device for simulating natural illumination comprising a first optical unit in turn comprising a primary light source comprising a diffusion chamber within which ends at least one emission termination of an optical fiber configured to be connected upstream to a natural light source, such as a sunlight collection unit, and / or an artificial light source, the primary light source being configured to emit primary light in the visible spectrum and with a primary light correlated color temperature CCTP, and a dichroic separating optic configured to intercept at least part of the primary light generated by the primary light source and emit, from a first emitting surface, at least one strongly collimated first light component having a propagation direction, generated from the primary light, and at least one diffuse light component. The at least one first strongly collimated light component and the at least one diffuse light component form a light with chromatic components with different angular distributions.

[0012] In addition, the light with chromatic components with different angular distributions has a total flux and a light intensity profile characterized by a first angular aperture a less than 40° measured as half-width at half-maximum (HWHM) with reference to at least one semi section plane of the dichroic separating optic containing the propagation direction.

[0013] Still further, the dichroic separating optic is configured such that, when the primary light correlated color temperature CCTPis substantially equal to or higher than 5000 K, the light with chromatic components with different angular distributions has a greater correlated color sum temperature CCTSwhen measured at at least one measurement angle greater than 1.5 times the first angular aperture a than when measured at an angle 0° to the propagation direction.

[0014] There is also provided a second optical unit comprising a secondary collimating optic configured to receive as input at least part of the light with chromatic components with different angular distributions emitted from the first emitting surface and emit as output, starting from this light with chromatic components with different angular distributions, a weakly collimated light component and a second strongly collimated light component forming a collimated lightwith chromatic components with different angular distributions emitted by the second optical unit.

[0015] The secondary collimating optic is configured to intercept at least the light with chromatic components with different angular distributions emitted from the first emitting surface at angles higher than a cut-off angle, measured with respect to the propagation direction, wherein the cutoff angle is less than 85°, preferably less than 80°, more preferably less than 75°.

[0016] Furthermore, the collimated light with chromatic components with different angular distributions emitted by the secondary collimating optic has substantially the same luminous flux, integrated over an angular range of angles between 0° and the first angular aperture a, with respect to a luminous flux of the light with chromatic components with different angular distributions integrated over the same angular range and / or a second angular aperture a’ of the light intensity profile less than or substantially equal to the first angular aperture a of the light intensity profile of the light with chromatic components with different angular distributions emitted by the first emitting surface.

[0017] Within the scope of the present description and in the appended claims, by “substantially equal luminous flux” is meant a luminous flux that varies less than 20%, preferably less than 15%, more preferably less than 10%.

[0018] The illumination device for simulating natural illumination thus conceived is able to generate a light with two chromatic components with different angular distributions, offering an increased energy efficiency with respect to the state of the art due to the possibility of making use of sunlight itself, conveyed in the device through the at least one emission termination of an optical fiber. In particular, the light emitted by the optical fiber is used in combination with a diffusion chamber that acts on the light emitted by the at least one emission termination of an optical fiber, so that it is no longer attributable to a specific emission position within the chamber itself and / or to a specific divergence of the light emitted by the optical fiber. This is particularly useful when within the diffusion chamber ends a plurality of optical fiber emission termination points, making the illumination device according to the invention usable indifferently in association with sunlight collection systems that supply the illumination devices through a single fiber or a plurality of fibers.

[0019] At the same time, the illumination device according to the invention is able to effectively prevent the light at higher color temperature (bluish light) from generating glare effects.

[0020] In this way, the illumination device according to the invention can be validly used both as a secondary illumination device, to support illumination systems for simulating natural illumination, in particular to systems operating from sunlight itself, since the generation of thechromatic components with different angular distributions allows to support the natural illumination effects that these systems reproduce, both as localized natural illumination, capable of providing good illumination efficiency in the absence of glare effects.

[0021] Finally, in the context of medical -diagnostic nuclear magnetic resonance (MRI) applications, the device can operate without generating electrical or magnetic disturbances and can also be devoid of electrical circuits in its inside and receive light from the outside through one or more optical fibers, whether they are in turn supplied by natural or artificial light.

[0022] According to a second aspect thereof, the present invention is directed to an illumination system comprising at least one illumination device for simulating natural illumination as described above, and a sunlight collection system comprising at least one collector element associated with at least one optical fiber whose emission termination ends inside the diffusion chamber of the at least one illumination device.

[0023] Advantageously, the illumination system thus configured makes it possible to achieve the same advantages as described with reference to the illumination device for simulating natural illumination according to the invention.

[0024] The present invention may have at least one of the preferred following features; the latter may in particular be combined with one another as desired in order to meet specific application needs.

[0025] Preferably, the diffusion chamber is configured to angularly redistribute by reflection and / or diffusion an emitted and / or light entering therein and emit from an emitting surface a diffuse light.

[0026] More preferably, the diffusion chamber is configured to emit from an emitting surface a substantially uniform and / or substantially isotropic diffuse light with respect to the emitting surface or a Lambertian light.

[0027] Preferably the diffusion chamber comprises at least a portion of an interior wall configured to diffusely and / or specularly reflect, a light incident on it; and / or at least a diffuse wall portion configured to diffuse a light incident on the diffuse wall portion itself outwards from the diffusion chamber.

[0028] Preferably, the diffusion chamber comprises an inner surface that substantially covers it entirely, made of a material that does not substantially absorb visible light.

[0029] Preferably the diffusion chamber has a transmission efficiency equal to at least 50%, preferably equal to at least 70%.

[0030] More preferably at least a portion of an interior wall configured to diffusely and / or specularly reflect a light incident on the same comprises at least one back wall of the diffusion chamber atwhich ends the at least one emission termination of an optical fiber and / or at least one perimeter side wall surrounding the back wall.

[0031] Preferably, within the diffusion chamber ends a plurality of emission terminations of respective optical fibers such as for example at least two emission terminations of respective optical fibers, or at least four emission terminations of respective optical fibers, or still at least six emission terminations of respective optical fibers.

[0032] In a preferred embodiment, within the diffusion chamber ends a connector in which a plurality of emission terminations of respective optical fibers converges, such as at least two emission terminations of respective optical fibers, or at least four emission terminations of respective optical fibers, or still at least six emission terminations of respective optical fibers.

[0033] Preferably, within the diffusion chamber there is comprised at least one balancing light source, preferably at least one solid-state light-emitting device, such as an LED or a plurality of LEDs of different colors.

[0034] Advantageously, sunlight is used in addition to a balancing source in order to be able to offer a sufficient degree of illumination, regardless of weather conditions and / or time of day. To this end, the diffusion chamber acts on the light emitted by the balancing source and by the at least one emission termination of an optical fiber, making sure that it is no longer attributable to a specific emission position within the chamber itself. In this way, the user does not perceive any difference, regardless of the active light source.

[0035] Preferably, the illumination system comprises at least one light sensor placed at the at least one collector element and a control unit connected to the at least one light sensor and to the at least one illumination device, wherein the control unit is configured to implement measures to control the operation of the at least one illumination device on the basis of information provided by the at least one light sensor.

[0036] More preferably, the illumination system comprises a chromatic filter and / or a shutter placed at the at least one collector element and controllable through the control unit in such a way as to stabilize chromaticity and / or the total amount of sunlight supplied by the at least one collector element to the illumination device.

[0037] Preferably, the light with chromatic components with different angular distributions has a light intensity profile characterized by a first angular aperture a less than 30°, more preferably less than 20°, more preferably less than 15°, measured as half-width at half-maximum (HWHM) with reference to the at least one semi section plane of the dichroic separating optic containing the propagation direction.

[0038] Preferably, the secondary collimating optic generates, starting from the light with chromatic components with different angular distributions, the collimated light with chromatic components with different angular distributions with a light intensity profile, referred to the semi section plane, characterized by an average value in an attenuation angular range between an angle of attenuation y and 90°, lower than the average value of the light intensity profile of the light with chromatic components with different angular distributions, calculated with respect to the same attenuation angular range.

[0039] Within the scope of the present invention and in the appended claims with “attenuation angular range” it is intended to indicate a non-zero angular range, such as for example of at least 5°, preferably of at least 10°, more preferably of at least 15°.

[0040] In a variant of the invention, the secondary collimating optic is configured to generate the collimated light with chromatic components with different angular distributions having a light intensity profile, referred to the semi section plane, characterized by an average value of less than 60%, preferably less than 40%, more preferably less than 20% of the average value of the light intensity profile of the light with chromatic components with different angular distributions, calculated with reference to the attenuation angular range.

[0041] The secondary collimating optic is also preferably configured to substantially(i) not intercept the light with chromatic components with different angular distributions emitted from the first emitting surface at angles less than the first angular aperture a, and / or(ii) not increase the luminous flux at angles greater than the first angular aperture a by redistributing the light with chromatic components with different distributions, and / or(iii) not decrease the luminous flux at angles less than the first angular aperture a.

[0042] In particular, the secondary collimating optic is configured to intercept less than 10% of the total flux of the light with chromatic components with different angular distributions exiting from the first emitting surface 25 at angles less than the first angular aperture, preferably less than 5%, more preferably less than 2%.

[0043] In a variant, the secondary collimating optic is configured not to increase the luminous flux of the light with chromatic components with different angular distributions at angles greater than the first angular aperture a by more than 10%, preferably by more than 5%, more preferably by more than 2%.

[0044] In another variant, the secondary collimating optic is configured not to decrease the luminous flux of the light with chromatic components with different angular distributions at anglessmaller than the first angular aperture a by more than 10%, preferably by more than 5%, more preferably by more than 2%.

[0045] In a variant of the invention, the secondary collimating optic is made in the shape of a reflection optic configured in such a way as to intercept and reflect the light with chromatic components with different angular distributions emitted from the first emitting surface at angles higher than the cut-off angle.

[0046] Alternatively or in addition, the secondary collimating optic is made in the shape of a refractive lens configured to intercept and redirect the light with chromatic components with different angular distributions emitted from the first emitting surface at angles higher than the cut-off angle.

[0047] Preferably, the refractive lens is configured to intercept and redirect at least part of the light with chromatic components with different angular distributions in such a way as to generate the collimated light with chromatic components with different angular distributions having a light intensity profile characterized by a second angular aperture a’ measured as half-width at halfmaximum (HWHM) with reference to the semi section plane less than or equal to, preferably less than, the first angular aperture a.

[0048] Alternatively or in addition, the secondary collimating optic is a structure comprising walls having at least a portion made of a material with a diffuse reflectance of at least 50%, preferably of at least 55%, more preferably of at least 60%.

[0049] Alternatively or in addition, the secondary collimating optic is a structure comprising walls having at least a portion made of a material with an absorption coefficient in the visible equal to at least 70%, more preferably equal to at least 80%, even more preferably equal to at least 90% of the incident light and positioned so as to intercept and / or absorb at least part of the light emitted from the first emitting surface at angles greater than the cut-off angle r.

[0050] In the context of this description and in the subsequent claims, the terms “absorption coefficient”, “regular reflectance” and “diffuse reflectance” refer to the definitions provided in the E284 standard relating to the terminology describing the appearance of materials and light sources (ASTM E284 -09a, Standard Terminology of Appearance, ASTM International, West Conshohocken, PA, 2009).

[0051] Preferably, the secondary collimating optic is configured to substantially not modify the correlated color temperature CCT of the light components of the light with chromatic components with different angular distributions emitted by the first optical unit.

[0052] Preferably, the secondary collimating optic is configured to generate, starting from the light with chromatic components with different angular distributions emitted from the first emittingsurface, a weakly collimated light component having a correlated color temperature substantially equal to a second correlated color temperature CCT2 of the diffuse light component of the light emitted from the first emitting surface and a second strongly collimated light component having a correlated color temperature substantially equal to a first correlated color temperature CCTi of the first strongly collimated light component of the light emitted from the first emitting surface.

[0053] In a variant of the invention, with reference to the semi section plane, an angular aperture P of the weakly collimated light component measured as half-width at half-maximum (HWHM) of the light intensity profile is at least 1.2 times greater, preferably at least 1.5 times greater, more preferably at least 2 times greater than the first angular aperture a measured as half-width at half-maximum (HWHM) of the intensity profile of the light with chromatic components with different angular distributions.

[0054] In a variant of the invention, the dichroic separating optic comprises a primary collimating optic configured to generate the light with chromatic components with different angular distributions having light intensity profile with the first angular aperture a starting from the primary light, and a diffuse light generator configured to generate the diffuse light component at the second correlated color temperature.

[0055] Preferably, the diffuse light generator is a chromatic diffusion element configured to be substantially transparent to at least a first spectral portion of a light incident on it and to diffuse at least a second spectral portion of the incident light.

[0056] Within the scope of the present description and in the appended claims, by “first spectral portion” is meant a spectral portion comprising wavelengths greater than the wavelengths comprised in the second spectral portion.

[0057] Within the scope of the present description and in the appended claims by “generator of diffuse light substantially transparent in a spectral region” is meant a generator of diffuse light that transmits at least 50%, preferably at least 60%, more preferably at least 70% of the incident light on a surface thereof in a certain spectral region, for example in the spectral region of red, or for wavelengths around 650nm, net of Fresnel reflection losses.

[0058] Within the scope of the present description and in the appended claims by “diffuse light generator configured to diffuse at least a second spectral portion of the incident light” is meant a diffuse light generator that diffuses at least 10%, preferably at least 20%, more preferably at least 30% of the light incident on a surface thereof in a certain spectral region, for example in the spectral region of blue or for wavelengths around 450nm.

[0059] Alternatively, the diffuse light generator is a chromatic diffusion element configured to preferably diffuse the shorter wavelengths with respect to the longer wavelengths, i.e. to preferably diffuse blue light with respect to red light, e.g. to diffuse a light at 450nm at least 1.5 times more effectively, preferably at least 2 times more effectively, preferably at least 3 times more effectively than a light at 650nm, and / or to preferably transmit red light with respect to blue light, i.e. to transmit a light at 650nm at least 1.1 times more effectively, preferably at least 1.2 times more effectively, preferably at least 1.3 times more effectively than a light 450nm.

[0060] Alternatively or in addition, the diffuse light generator is a chromatic diffusion element of the adjustable type, being configured to vary mainly the diffusion element efficiency of the chromatic diffusion element for at least the second spectral portion of the incident light, thereby adjusting the diffusion element efficiency of the second spectral portion of the incident light.

[0061] Alternatively or in addition, the diffuse light generator is a chromatic diffusion element of the adjustable type comprising a matrix made of polymeric material in which nanodroplets containing liquid crystals are trapped.

[0062] Alternatively or in addition, the diffuse light generator is a chromatic diffusion element in the shape of a panel, a film, a surface coating layer or a surface anodizing layer.

[0063] Alternatively or in addition, the diffuse light generator is a diffuse light generator of the active type, capable of generating diffuse light independently of the primary light source, and made of a material substantially transparent to light, irrespective of the spectrum thereof. In particular, the diffuse light generator is an edge-lit diffusive light guide.

[0064] More preferably, the chromatic diffusion element is placed at the first emitting surface or at at least one surface of interaction between said primary light and said primary collimation element.

[0065] In a variant of the invention, at least the primary collimation optical element of the dichroic separating optic has axial symmetry and the propagation direction is comprised in a symmetry axis of the primary collimation optical element; and the diffuse light generator has a circular or quadrilateral section - such as for example a square or rectangular - or polygonal section.

[0066] In a variant of the invention, the first optical unit comprises a plurality of primary light sources, for example arranged side by side and / or aligned along the development axis, and wherein the dichroic separating optic comprise at least one collimation lens associated with the plurality of primary light sources and configured to collimate the light emitted by each of the primary light sources around a respective propagation direction of a plurality of parallel propagation directions.Brief Description of the Drawings

[0067] The accompanying drawings, which are incorporated herein and form part of the description, illustrate exemplary embodiments of the present invention and, together with the description, are intended to illustrate the principles of the present invention.In the drawings:Fig. 1 is a schematic representation of a first embodiment of the illumination device for simulating natural illumination according to the present invention;Fig. 2 is a schematic representation of a second embodiment of the illumination device for simulating natural illumination according to the present invention;Fig. 3 is a schematic representation of a third embodiment of the illumination device for simulating natural illumination according to the present invention;Fig. 4 is a schematic representation of a fourth embodiment of the illumination device for simulating natural illumination according to the present invention;Fig. 5 is a schematic representation of a fifth embodiment of the illumination device for simulating natural illumination according to the present invention;Fig. 6 is a schematic representation of a sixth embodiment of the illumination device for simulating natural illumination according to the present invention;Fig. 7 is a schematic representation of a sunlight collection system connected to an illumination device for simulating natural illumination according to the present invention; andFig. 8 is a schematic representation of an embodiment of an illumination system comprising a plurality of illumination devices for simulating natural illumination according to the present invention.Detailed Description

[0068] The following is a detailed description of exemplary embodiments of the present invention. The exemplary embodiments described herein and illustrated in the drawings are intended to teach the principles of the present invention, enabling the person skilled in the art to implement and use the invention in different contexts and / or for different applications. Therefore, the exemplary embodiments are not intended, nor should they be considered, to limit the scope of patent protection. Rather, the scope of patent protection is defined by the attached claims.

[0069] With reference to Fig. 1, there is schematically illustrated an illumination device for simulating natural illumination, hereinafter referred to as “illumination device” for brevity’s sake, according to a first embodiment of the present invention, collectively referred to as 10.

[0070] The illumination device 10 comprises a first optical unit 20 and a second optical unit 30 optically coupled to each other in such a way that the second optical unit 30 intercepts at least part of the light emitted by the first optical unit 20.

[0071] In detail, the first optical unit 20 comprises at least one primary light source 21 configured to emit a primary light 22 comprising at least one set of electromagnetic radiations having wavelength comprised in the visible spectrum (i.e., 380 nm < < 740 nm), also indicated with the terms Tight beam’, Tight ray’ or Tight’ in the following and with a primary light correlated color temperature CCTP.

[0072] According to the present invention, the primary light source 21 comprises a diffusion chamber 14 within which at least one emission termination 15A of an optical fiber 15 connectable upstream to a light source, such as for example to a sunlight collection system 40, shown by way of example in Fig. 7, or alternatively to an artificial light source, such as an LED source.

[0073] As shown in Fig. 2, a plurality of emission terminations 15A of respective optical fibers 15 may extend within the diffusion chamber 14, such as for example at least two emission terminations 15a, or at least four emission terminations 15a, or still at least six emission terminations 15a. The plurality of emission terminations 15A of respective optical fibers 15 may extend within the diffusion chamber 14 in a distributed manner and not strictly concentrated in a single input position.

[0074] The diffusion chamber 14 is configured to angularly redistribute by reflection and / or diffusion the light that is emitted therein. The diffusion chamber 14 preferably comprises at least a portion of an interior wall 14A capable of diffusely and / or specularly reflecting a light incident on it and a diffusive screen 14B configured to diffuse the light incident on it 14B outwards from the diffusion chamber 14. By way of example, in the embodiment illustrated in Fig. 1, the diffusion chamber 14 comprises a first reflective interior wall 14A, made in several portions, arranged substantially parallel to a direction in which the intensity of light emission from the diffusion chamber 14 is maximum, and a second reflective interior wall 14A, substantially orthogonal to the emission direction of the chamber 14 and defining a back wall of the chamber 14. The at least one portion of an interior wall 14A preferably comprises a back wall of the diffusion chamber 14 at which ends the at least one emission termination 15A of an optical fiber 15. Alternatively or in addition, the at least a portion of an interior wall 14A preferably comprises a perimeter side wall surrounding and delimiting the back wall. The diffusive screen 14B is preferably placed facing the back wall and adjoins the perimeter side wall in such a way as to close the diffusion chamber 14.

[0075] In one aspect, thanks to the presence of the diffusion chamber 14, the light emitted downstream of the diffusion screen 14B is no longer attributable to a specific emission position inside the chamber 14, being emitted by the screen 14B with a different light intensity profile with respect to the light emitted inside the diffusion chamber 14, upstream of the screen 14B. This is because the light intensity profile of the light emitted from the screen 14B is obtained by the combination of the reflections and diffusions for which the diffusion chamber 14 is configured. By way of example, the light is emitted from the screen 14B in a substantially uniform manner with respect to its surface or in a Lambertian manner.

[0076] In the illustrated embodiments, in addition to the at least one emission termination 15A of an optical fiber 15, within the diffusion chamber 14 there is preferably also provided a balancing light source 16, for example a solid state light-emitting device (LED), which may be employed to balance illumination coming from sunlight provided through the optical fibers 15.

[0077] The first optical unit 20 further comprises at least one dichroic separating optic 23 having a first light-emitting surface 25 from which a light 24 with chromatic components with different angular distributions is emitted. The primary light source 21 is positioned so as to substantially introduce the primary light 22 into the dichroic separating optic 23.

[0078] The dichroic separating optic 23 is configured to generate, starting from the primary light 22 emitted by the primary light source 21, at least a first strongly collimated light component 24a that crosses the first emitting surface 25 and propagates along a propagation direction A, with the propagation direction A coinciding with the direction along which the first strongly collimated light component 24a has maximum light intensity, and a diffuse light component 24b that crosses the first emitting surface 25 propagating in substantially all directions. For example, the diffuse light component 24b has a substantially Lambertian light intensity profile.

[0079] A substantially Lambertian emission profile is understood to mean an emission profile proportional to the cosine of the emission angle, with emission angle equal to 0° for the direction normal to the emitting surface.

[0080] In particular, the at least one first strongly collimated light component 24a is characterized by a first correlated color temperature or CCTi, while the at least one diffuse light component 24b is characterized by a second correlated color temperature or CCT2 different, in particular higher, than the correlated color temperature CCT 1 of the first strongly collimated light component 24a.

[0081] Specifically, the first strongly collimated light component 24a and the diffuse light component 24b together form the light with chromatic components with different angular distributions 24. The light with chromatic components with different angular distributions 24 is therefore characterized by a light intensity profile - referred to at least one semi section plane X of thedichroic separating optic 23 containing the propagation direction A - which has a first angular aperture a - measured in terms of half-width at half-maximum (HWHM) - less than 40°, preferably less than 30°, more preferably less than 20°, more preferably less than 15°. The light with chromatic components with different angular distributions 24 is also characterized by a non-zero light intensity profile for angles higher than 2 times the first angular aperture a.

[0082] A non-zero light intensity profile at a given angle means a profile characterized by a light intensity at that angle that is greater than 0.1% of the light intensity of the light 24 with chromatic components with different angular distributions in the propagation direction.

[0083] Furthermore, the light with chromatic components with different angular distributions 24, when the primary light correlated color temperature CCTPis equal to at least 5000 K, has a correlated color sum temperature CCTS1.2 times lower, preferably 1.3 times lower, more preferably 1.4 times lower when measured at an angle of 0° with reference to the propagation direction A, than when measured at at least one measurement angle greater than 1.5 times the angular aperture a, for example at a measurement angle equal to 2 times the angular aperture a or at a measurement angle equal to 75°.

[0084] In particular, the correlated color sum temperature CCTSassumes a substantially constant value around the propagation direction A. Preferably, the correlated color sum temperature CCTSassumes a substantially constant value for angles less than 0.2 times the first angular aperture a, preferably for angles less than 0.5 times the first angular aperture a, more preferably for angles less than the first angular aperture a. Within the scope of the present description and in the appended claims, by “substantially constant correlated color temperature” is meant a correlated color temperature that varies less than 10%, preferably less than 5%, more preferably less than 3%.

[0085] In exemplary terms, the dichroic separating optic 23 comprise a primary collimation optical element 23a, for example a total internal reflection ( I ) lens as shown in Fig. 1 or a reflector as shown in Fig. 2, and a diffuse light generator 23b, 23b’, 23b”, which in the embodiment of Fig. 1 is made in the shape of a chromatic diffusion element 23b, placed downstream of the primary collimating optical element 23a in such a way as to intercept the collimated light at the output. As better illustrated below, the chromatic diffusion element 23b generates the diffuse light component 24b with correlated color temperature CCT2 higher than the light 24 with chromatic components with different angular distributions emitted from the first emitting surface 25.

[0086] The primary collimating optical element 23 a of the embodiment of Fig. 1 has axial symmetry, thus resulting in that the light intensity profile of the light with chromatic components withdifferent angular distributions 24 is substantially the same with reference to any semi section plane X of the dichroic separating optic 23 containing the propagation direction A. The chromatic diffusion element 23b can itself be made with axial symmetry, for example with a circular plan, or it can not have axial symmetry having a quadrilateral plan, such as for example a square or rectangular plan, or regular polygonal or not.

[0087] “Chromatic diffusion element” means a diffuser element whose light-diffusing properties depend on the wavelength of the light crossing it, such as for example a Rayleigh diffuser or Rayleigh-like diffuser. This type of diffuser is characterized by being substantially transparent to, or having negligible interaction with, a first spectral portion of the light incident on the same.

[0088] The first spectral portion of the incident light therefore crosses the chromatic diffusion element 23b in a substantially unaltered manner and - being collimated following the action of the primary collimating optical element 23a - contributes to generating, downstream of the chromatic diffusion element 23b, the first strongly collimated light component 24a of the light 24 with chromatic components with different angular distributions that has lower correlated color temperature CCTi, where “downstream” is understood with respect to the propagation direction A. On the contrary, the chromatic diffusion element 23b mainly acts on a second spectral portion of the light incident on it, diffusing it in a significant way and thus giving rise to the diffuse light component 24b of the light 24 with chromatic components with different angular distributions which has a higher correlated color temperature CCT2, as it substantially lacks the wavelengths belonging to the first spectral portion.

[0089] The chromatic separation and the generation of the diffuse light component 24b with higher CCT2 (bluish light component) can be achieved by using a “thick” panel, as shown for example in Fig. 1, or a “thin” layer, illustrated in exemplary terms in Fig. 5 - which is generally referred to herein as “chromatic diffusion element 23b”- comprising a layer in a host material in which transparent nanometric diffusion elements (also known as “scattering elements”) are present in a predetermined amount per unit area and having a different refractive index with respect to the refractive index of the host material.

[0090] Such a chromatic diffusion element can be made in the shape of a panel, film, surface coating layer or even be a surface anodizing layer of a metal surface having specific structural characteristics described in detail in International Patent Application No. WO2021 / 209964, fiLED by the same Applicant and the contents of which are herein entirely referred to and incorporated by reference.

[0091] Again, the chromatic diffusion element may be of the adjustable type, whereby the intensity of interaction between the chromatic diffusion element and the incident light may be adjusted,thereby modifying the diffusion efficiency in particular of the second spectral portion of the incident light, i.e. the portion of the incident light on which the chromatic diffusion element mainly acts. The chromatic diffusion elements of the adjustable type comprise, for example, a matrix made of polymeric material (host material) in which so-called nanodroplets containing liquid crystal (LC) molecules (diffusion nanometric elements) are trapped. The liquid crystals cause an anisotropy in the refractive index, which therefore makes it possible to adjust the jump in the refractive index between the liquid crystal nanodroplets and the host material by varying an applied voltage. In general terms, the index variation is due to the fact that the liquid crystal molecules inside each nanodroplet tend to align when an electric field is applied, having a degree of alignment that can be modified according to the magnitude of the applied voltage. For further details, reference is made to International Patent Application No. WO 2018 / 091150 of the same Applicant and the contents of which are fully referred to and incorporated herein by reference.

[0092] Unlike the embodiment of Fig. 1, the embodiment illustrated in Fig. 2 comprises a diffuse light generator 23b’ of the active type - i.e. capable of generating diffuse light 23b’ independently of the primary light source 21 - placed downstream of the primary collimating optical element 23 a. In particular, the diffuse light generator 23b’ generates the diffuse light component 24b with higher correlated color temperature CCT2 than the light 24 with chromatic components with different angular distributions emitted from the first emitting surface 25. In addition, the diffuse light generator 23b’ is made of a material that is substantially transparent to light, independently of the spectrum thereof. In this way, almost all of the collimated light exiting from the primary collimation optical element 23a intercepted by the diffuse light generator 23b’ propagates downstream of the same with respect to the propagation direction A, giving rise to the first strongly collimated light component 24a of the light 24 with chromatic components with different angular distributions emitted from the first emitting surface 25.

[0093] The second optical unit 30 comprises at least one secondary collimating optic 33 having a lightintroducing surface 36, placed downstream of the first emitting surface 25 of the first optical unit 20 and in such a way as to intercept at least part of the light 24 with chromatic components with different angular distributions emitted by the first optical unit 20, and a second lightemitting surface 35 from which a collimated light 34 with chromatic components with different angular distributions is emitted.

[0094] In particular, the secondary collimating optic 33 is configured to interact with the light 24 with chromatic components with different angular distributions emitted by the first optical unit 20 in such a way as to generate, downstream of the second light-emitting surface 35, a weaklycollimated light component 34b and a second strongly collimated light component 34a, wherein the set of such light components 34a, 34b forms the collimated light 34 with chromatic components with different angular distributions emitted by the second light-emitting surface 35 of the second optical unit 30.

[0095] The secondary collimating optic 33 is configured and arranged to intercept at least the light part with chromatic components with different angular distributions 24 emitted from the first emitting surface 25 of the first optical unit 20 at angles higher than a cut-off angle T, measured with respect to the propagation direction A. In other words, the secondary collimating optic 33 is configured to prevent direct view of the dichroic separating optic 23, i.e. of the first light emitting surface 25, from observation angles between the cut-off angle r and 90°. By this is meant that a line exiting from the first light emitting surface 25 with an inclination greater than the cut-off angle r with respect to the propagation direction A is intercepted by the secondary collimating optic 33. In particular, T is less than 85°, preferably less than 80°, more preferably less than 75°. For example, T is in the range between 1.2 times a and 85°, preferably between 1.5 times a and 80°, more preferably from 2 times a and 75°.

[0096] In one embodiment, the collimated light 34 with chromatic components with different angular distributions has a light intensity profile, referred to the at least one semi section plane X of the dichroic separating optic 23, characterized by an average value calculated with reference to an attenuation angular range between an angle of attenuation y and 90°, lower than the average value of the light intensity profile of the light with chromatic components with different angular distributions 24, calculated with respect to the same attenuation angular range. Specifically, the attenuation angular range is a non-zero angular range, such as for example of at least 5°, preferably of at least 10°, more preferably of at least 15°.

[0097] For example, the secondary collimating optic 33 is configured to generate a collimated light 34 with chromatic components with different angular distributions having a light intensity profile referred to the semi section plane X characterized by an average value of less than 60%, preferably less than 40%, more preferably less than 20% of the average value of the light intensity profile of the light with chromatic components with different angular distributions 24 exiting from the first emitting surface 25, calculated in the attenuation angular range, i.e. the angular range between the angle of attenuation y and 90°. This ensures that the illumination device 10 is characterized by a minimal glare for angles within the attenuation angular range, with reference to the at least one semi section plane X, while maintaining high luminous efficiency levels of the illumination device.

[0098] In addition or alternatively, the secondary collimating optic 33 is configured to interact with the light 24 with chromatic components with different angular distributions emitted from the first emitting surface 25 in such a way as to generate a collimated light 34 with chromatic components with different angular distributions having substantially the same luminous flux integrated over an angular range of angles between 0° and the first angular aperture a of the light with chromatic components with different angular distributions 24, with respect to a luminous flux of the light with chromatic components with different angular distributions 24 integrated over the same angular range.

[0099] In addition or alternatively, the secondary collimating optic 33 is configured to interact with the light 24 with chromatic components with different angular distributions emitted from the first emitting surface 25 in such a way as to generate a collimated light 34 with chromatic components with different angular distributions a second angular aperture a’ of the light intensity profile equal to or less than the first angular aperture a of the light intensity profile of the light with chromatic components with different angular distributions 24 emitted from the first emitting surface 25.

[0100] For example, the secondary collimating optic 33 does not intercept the light with chromatic components with different angular distributions 24 exiting from the first emitting surface 25 at angles substantially lower than the first angular aperture a, as shown in Figs. 1-3. Alternatively, the secondary collimating optic 33 interacts with the light with chromatic components with different angular distributions 24 in such a way as to substantially not increase the luminous flux at angles greater than the first angular aperture a and / or in such a way as not to decrease the luminous flux at angles less than the first angular aperture a, as shown in Fig. 4. In particular, the secondary collimating optic 33 is configured to maintain substantially unaltered or at most reduce the angular aperture of the light intensity profile of the light with chromatic components with different angular distributions 24 and / or to substantially not modify the flux thereof in the range from 0° to a. For example, the secondary collimating optic 33 is configured to intercept less than 10% of the total flux of the light with chromatic components with different angular distributions 24 exiting from the first emitting surface 25 at angles less than the first angular aperture a, preferably less than 5%, more preferably less than 2%.

[0101] In particular, the secondary collimating optic 33 is configured to substantially not modify the correlated color temperature CCT of the light components of the light 24 with chromatic components with different angular distributions emitted by the first optical unit 20. At the exit from the second light-emitting surface 35, a weakly collimated light component 34b having a correlated color temperature substantially equal to the second correlated color temperatureCCT2 of the diffuse light component 24b of the light 24 emitted by the first optical unit 20 and a second strongly collimated light component 34a having a correlated color temperature substantially equal to the first correlated color temperature CCTi of the first strongly collimated light component 24a of the light 24 emitted from the first emitting surface 25 are thus generated.

[0102] In particular, the weakly collimated light component 34b is characterized by a light intensity profile with an angular aperture P greater than the angular aperture of the intensity profile of the second strongly collimated light component 34a and / or with an angular aperture P greater than the first angular aperture a of the intensity profile of the light with chromatic components with different angular distributions 24, where the intensity profiles refer to the at least one semi section plane X of the dichroic separating optic 23.

[0103] For example, the angular aperture P of the weakly collimated light component 34b has a halfwidth at half-maximum (HWHM) 1.2 times greater, preferably 1.5 times greater, more preferably 2 times greater than the half-width at half-maximum (HWHM) of the angular aperture a of the intensity profile of the light with chromatic components with different angular distributions 2.

[0104] In the embodiment of Fig. 1 and Fig. 2, the secondary collimating optic 33 is a structure comprising internally opaque walls positioned so as to reflect diffusely at least part of the diffuse light component 24b that is emitted at angles higher than the angle of attenuation y. To this end, the material of which these walls are composed has a diffuse reflectance equal to at least 50%, preferably of at least 55%, more preferably of at least 60%.

[0105] With reference to Fig. 3 a different embodiment of the illumination device 10 is illustrated schematically. In particular, the embodiment of Fig. 3 differs from the first embodiment in the implementation of the dichroic separating optic 23 and of the secondary collimating optics 33.

[0106] In the embodiment of Fig. 3, the dichroic separating optic 23 comprises a diffuse light generator 23b’ of the active type. In addition, the secondary collimating optic 33 is made in the shape of a reflector, thus internally comprising reflective walls and configured in such a way as to intercept and reflect at least part of the light with chromatic components with different angular distributions 24 and redistribute it in such a way as to attenuate it for angles higher than the angle of attenuation y, measured with respect to the propagation direction A and equal to at least 2 times, preferably 2.5 times, more preferably 3 times, the angular aperture a of the light intensity profile of the light 24 with chromatic components with different angular distributions, with reference to the at least one semi section plane X. For this purpose, the material of which the interior walls are composed has a regular reflection of at least 60%, preferably of at least 65%, more preferably of at least 70%. Furthermore, thesecondary collimating optic 33 is configured in such a way as not to intercept the light with chromatic components with different angular distributions 24 emitted from the first emitting surface 25 at angles less than the first angular aperture a.

[0107] With reference to Fig. 4 another embodiment of the illumination device 10 according to the invention is schematically illustrated. In particular, the embodiment of Fig. 4 differs from the previous embodiments in the implementation of the secondary collimating optics 33.

[0108] In detail, in the embodiment of Fig. 4, the secondary collimating optic 33 is made in the shape of a refractive lens configured to interact with the light with chromatic components with different angular distributions 24 emitted from the first emitting surface 25 of the first optical unit 20 in such a way as to attenuate its light intensity for angles higher than the angle of attenuation y, with reference to the at least one semi section plane X. A collimated light with chromatic components with different angular distributions 34 is thus generated downstream of the second emitting surface 35, having an average value of the calculated light intensity profile for the angles between the angle of attenuation y and 90°, lower than the average value calculated on the same angular range of the light intensity profile of the light with chromatic components with different angular distributions 24.

[0109] Furthermore, the secondary collimating optic 33 is configured in such a way as to collimate the light with chromatic components with different angular distributions 24 emitted from the first emitting surface 25, thus obtaining downstream of the second emitting surface 35 a collimated light with chromatic components with different angular distributions 34 having a second angular aperture a’ of the light intensity profile lower than the first angular aperture a of the light intensity profile of the light 24 with chromatic components with different angular distributions emitted from the first emitting surface 25. In other words, the secondary collimating optic 33 is configured to generate the collimated light with chromatic components with different angular distributions 34 starting from the light 24 with chromatic components with different angular distributions emitted from the first emitting surface 25, keeping its integrated flux substantially unaltered over an angular range of angles between 0° and the first angular aperture a and reducing its angular aperture of the light intensity profile in the reference semi plane.

[0110] At the exit from the second light-emitting surface 35 there are thus the weakly collimated light component 34b at higher correlated color temperature CCT2 and the second strongly collimated light component 34a at lower correlated color temperature CCTi which form a collimated light with chromatic components with different angular distributions 34 characterized by a second angular aperture a’ of the light intensity profile lower than the first angular aperture a of the light intensity profile of the light 24 with chromatic components with different angulardistributions exiting from the first optical unit 20 and a flux integrated over an angular range of angles between 0° and the first angular aperture a substantially equal to the flux of said light 24 with chromatic components with different angular distributions integrated in the same angular range.

[0111] With reference to Fig. 5 another embodiment of the illumination device 10 according to the invention is schematically illustrated. In particular, the embodiment of Fig. 5 differs from the other embodiments in that the dichroic separating optic 23 are made in the shape of a reflector 23a with the walls interacting with the incident light emitted by the primary light source 21 - i.e. the internal reflecting walls - coated by a layer 23b” made of a chromatic diffusion material. The chromatic diffusion layer 23b” is, for example, applied by lamination if the material composing it is of the liquid crystal type. Alternatively, the layer is, for example, grown as an anodizing layer directly on the interior walls of the reflector 23a.

[0112] In this case, the light 22 emitted by the primary light source 21, being incident on the interior walls of the reflector 23a, is partly collimated and partly diffused. In particular, a first spectral portion of the incident light crosses the chromatic diffusion element layer 23b” two times (incident beam and reflected beam) in a substantially unaltered manner, thus undergoing almost exclusively the collimation action caused by the reflector 23 a. A second spectral portion of the incident light interacts, on the contrary, in a significant way with the chromatic diffusion layer 23b” that covers the interior walls of the reflector 23a, thus being mainly diffused.

[0113] In this way, two chromatic components with different angular distributions exiting the dichroic separating optic 23 are generated: the first strongly collimated light component 24a with lower correlated color temperature CCTi and the diffuse light component 24b with higher correlated color temperature CCT2.

[0114] In order to ensure that almost all of the second spectral portion of the emitted primary light 22 interacts with the chromatic diffusion element layer 23b”, thereby generating the diffuse light component 24b, the illumination device 10 may comprise a screen 27 positioned downstream of the primary light source 21 with respect to the propagation direction A in such a way as to block a direct exit of the light emitted by the primary light source 21 through the first emitting surface 25.

[0115] Fig. 6 shows a further embodiment of the illumination device 10 according to the invention in which the dichroic separating optic 23 are made in the shape of a TIR lens with a portion of the light input surface 26 coated with a chromatic diffusion layer 23b”.

[0116] In this case, the light 22 emitted by the primary light source 21, crossing the portion of the light input surface 26, is partly collimated and partly diffused. In particular, a first spectral portion ofthe light crosses the portion of the light input surface 26 - and so also the chromatic diffusion element layer 23b” - substantially unaltered, thereby undergoing the collimation action given by the lens 23 a. A second spectral portion of the light incident on the chromatic diffusion layer 23b”, on the contrary, interacts significantly with the same, thus being mainly diffused.

[0117] This results in the generation of two chromatic components with different angular distributions exiting from the dichroic separating optic 23 : the first strongly collimated light component 24a with lower correlated color temperature CCTi and the diffuse light component 24b with higher correlated color temperature CCT2.

[0118] Furthermore, in the embodiment of Fig. 6 the secondary collimating optic 33 is made in the shape of a structure comprising internally absorbent (dark) walls, positioned in such a way as to absorb at least part of the light with chromatic components with different angular distributions 24 emitted at angles higher than the angle of attenuation y, with reference to the at least one semi section plane X. For this purpose, the material of which these walls are composed has an absorption coefficient in the visible of at least 70%, more preferably 80%, even more preferably 90% of the light incident on it.

[0119] With reference to Fig. 7 there is shown a sunlight collection system 40 configured to collect sunlight during the day and to direct the collected light to the illumination device 10 through at least one optical fiber 15. In particular, the sunlight collection system 40 comprises at least one collector element 17 associated with at least one corresponding optical fiber 15, in particular, a set of collector elements 17 each associated with at least one corresponding optical fiber 15 of a plurality of optical fibers 15. The set of collector elements 17 may comprise a plurality of reflective or refractive optical elements, such as mirrors or lenses 17, mounted, for example, outside a building, such as on the roof of the building, to collect natural light. The lenses 17 allow, for example, to focus an incident sunlight 19 on an input face of the fiber 15 at an input end 15B thereof, so that the collected light propagates by internal reflection within the fiber 15 to an output face at the output end 15A of the fiber itself. In the illustrated preferred embodiment, each lens 17 is associated with a fiber. In alternative embodiments, not illustrated, each collector element may be associated with a fiber bundle comprising at least two fibers. In particular, each of the collector elements may be fixed or orientable in order to follow the change of direction of sunlight. Each collector element 17 comprises a sunlight input surface (not illustrated) having a surface area. The set of collector elements 17 associated with an illumination device 10 defines a sunlight collection surface given by the sum of the surface areas of each collector element 17 defining the set of collector elements 17. Advantageously, the first emitting surface 25 of the first optical unit 20 covers an area of less than 50 times,preferably less than 10 times, or even more preferably less than 5 times, or even more preferably less than 1 time, e.g. equal to 0.2 times the sunlight collection surface given by the set of collector elements 17. Advantageously, the illumination device 10 thus has a small mechanical footprint and, while having a high light intensity of the emitted light, is characterized by the absence of glare effects. This is due to the peculiar configuration of the secondary collimating optic 33 which guarantees compatibility with glare standards envisaged for the context of use (offices, hospitals, corridors).

[0120] Preferably, the first emitting surface 25 covers an area greater than or equal to one thousandth (1 / 1000), more preferably greater than or equal to one hundredth (1 / 100), of the sunlight collection surface given by the set of collector elements 17, thus further contributing to the prevention of glare effects.

[0121] The sunlight collection system 40 preferably comprises a control unit 18 configured to implement control measures during operation of the illumination device 10. For example, the control unit 18 is connected to a light sensor 13, positioned next to the plurality of lenses 17, through a first control line 13’. Accordingly, the light sensor 13 provides information on the outdoor light conditions. In addition, additional elements, such as a chromatic filter 11 or a shutter 12, may be present between each lens 17 and each input end of the fiber 15 A. The chromatic filter 11 may be selectable from a group of filters and / or controllable in its transmission to stabilize chromaticity and / or the total amount of sunlight supplied to the illumination device 10. The shutter 12 may be controlled to stabilize the amount of sunlight supplied to the illumination device 10. Therefore these additional elements can be connected to the control unit 18 by means of respective further control lines 11’, 12’.

[0122] Furthermore, the control unit 18 is preferably connected via a second control line 10’ to the illumination device 10. In particular, the balancing light sources 16 of the illumination device 10 are controlled through the control unit 18 in such a way as to stabilize the total amount of light supplied by the illumination device 10 and / or to stabilize the chromatic appearance of the direct light beam and / or of the diffuse light component. Examples of light sources for sunlight balancing include dynamic type light sources, such as an LED source controllable in the spectrum of the emitted light (color adjustment or CCT) and / or dimmable (light power adjustment). The balancing light source 16 may comprise a single LED or comprise a plurality of LEDs, e.g., a combination of blue LEDs, white LEDs, amber LEDs, cyan LEDs, green LEDs, and so on. The balancing light sources 16 contribute to the total light emerging from the diffusive screen 14B of the diffusion chamber 14 and can be controlled to compensate for thepower and color of the light beam supplied by the set of collector elements 17 in order to ensure a substantially constant light emission from the second light-emitting surface 35.

[0123] Fig. 9 shows an illumination system 50 for simulating natural illumination comprising a plurality of illumination devices 10 of the type illustrated in Fig. 2 wherein in particular the primary collimation optical element 23 a of the dichroic separating optic 23 has axial symmetry and wherein the illumination devices 10 are arranged so that the symmetry axes of the respective primary collimation optical element 23a are arranged parallel to each other. Furthermore, the illumination devices 10 are arranged in an extended structure on a plane perpendicular to each of the symmetry axes of the primary collimation optical element 23 a.

[0124] The invention thus conceived is susceptible to several modifications and variations, all falling within the scope of the inventive concept. For example, the secondary collimating optic 33 can be made in the shape of a structure comprising partly absorbing and partly reflecting interior walls, or partly opaque and partly reflecting or partly opaque and partly absorbing walls, being in any case configured in such a way as to absorb at least part of the light with chromatic components with different angular distributions 24 intercepted by the optic 33, and to reflect at least another part of the light with chromatic components with different angular distributions 24 intercepted by the optic 33, in such a way as to attenuate the light intensity of the light with chromatic components with different angular distributions 24 for angles higher than the angle of attenuation y in the at least one semi section plane X.

[0125] In conclusion, all the details can be replaced with other technically-equivalent elements.

Claims

AMENDED CLAIMS received by the International Bureau on 06 December 2024 (06.12.2024)1. Illumination device (10,50) for simulating natural illumination comprising: a first optical unit (20) comprising a primary light source (21) comprising a diffusion chamber (14) within which ends at least one emission termination (15 A) of an optical fiber (15) configured to be connected upstream to a natural light source, such as a sunlight collection unit (40), and / or an artificial light source, the primary light source (21) being configured to emit a primary light (22) in the visible spectrum and with a primary light correlated color temperature (CCTp), and dichroic separating optic (23) comprising a primary collimation optical element (23a) and a diffuse light generator (23b, 23b’, 23b”) placed downstream of the primary collimating optical element (23a) in such a way as to intercept the collimated light at the output, the dichroic separating optic (23) being configured to intercept at least part of the primary light (22) generated from the primary light source (21) and emit, from a first emitting surface (25), at least one first strongly collimated light component (24a) having a propagation direction (A), generated starting from the primary light (22), and at least one diffuse light component (24b), the at least one first strongly collimated light component (24a) and the at least a diffuse light component (24b) forming a light with chromatic components with different angular distributions (24), wherein the light with chromatic components with different angular distributions (24) has a total flux and a light intensity profile characterized by a first angular aperture (a) less than 40° measured as half-width at half-maximum (HWHM) with reference to at least one semi section plane (X) of the dichroic separating optic (23) containing the propagation direction (A), and wherein, when the primary light correlated color temperature (CCTP) is substantially equal to or higher than 5000 K, the light with chromatic components with different angular distributions (24) has a greater correlated color sum temperature (CCTS) when measured at at least one measurement angle higher than 1.5 times the first angular aperture (a) than when measured at an angle of 0° with respect to the propagation direction (A); and a second optical unit (30) comprising a secondary collimating optic (33) configured to receive as input at least part of the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25) and emit as output, starting from this light with chromatic components with different angular distributions (24), a weakly30AMENDED SHEET (ARTICLE 19)collimated light component (34b) and a second strongly collimated light component (34a) forming a collimated light (34) with chromatic components with different angular distributions emitted by the second optical unit (30), wherein the secondary collimating optic (33) is configured to intercept at least the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25) at angles higher than a cut-off angle (T), measured with respect to the propagation direction (A), wherein the cut-off angle (T) is less than 85°, preferably less than 80°, more preferably less than 75°; and wherein the collimated light (34) with chromatic components with different angular distributions emitted by the secondary collimating optic (33) has substantially the same luminous flux, integrated over an angular range of angles between 0° and the first angular aperture (a), with respect to a luminous flux of the light with chromatic components with different angular distributions (24) integrated over the same angular range and / or a second angular aperture (a’) of the light intensity profile substantially equal to or less than the first angular aperture (a) of the light intensity profile of the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25).

2. Illumination device (10,50) according to claim 1, wherein the diffusion chamber (14) is configured to angularly redistribute by reflection and / or diffusion an emitted and / or light entering therein and emit from an emitting surface (14B) a diffuse light, preferably a substantially uniform and / or substantially isotropic diffuse light with respect to the emitting surface (14B) or a Lambertian light.

3. Illumination device (10,50) according to claim 1 or 2, wherein the diffusion chamber (14) comprises: at least a portion of an interior wall (14A) configured to diffusely and / or specularly reflect light incident on it (14A); and / or at least one diffuse wall portion (14B) configured to diffuse a light incident on the diffuse wall portion itself (14B) outwards from the diffusion chamber (14); and / or wherein the diffusion chamber (14) comprises an inner surface that substantially covers it entirely, made of a material that does not substantially absorb visible light; and / or wherein the diffusion chamber (14) has a transmission efficiency equal to at least 50%, preferably equal to at least 70%.31AMENDED SHEET (ARTICLE 19)4. Illumination device (10,50) according to claim 3, wherein at least a portion of an interior wall (14A) configured to diffusely and / or specularly reflect a light incident on the same (14A) comprises at least one back wall of the diffusion chamber (14) at which ends the at least one emission termination (15 A) of an optical fiber (15) and / or at least one perimeter side wall surrounding the back wall.

5. Illumination device (10,50) according to any one of the preceding claims, wherein within the diffusion chamber (14) ends a plurality of emission terminations (15a) of respective optical fibers (15), such as at least two emission terminations (15 A) of respective optical fibers (15), or at least four emission terminations (15 A) of respective optical fibers (15), or at least six emission terminations (15 A) of respective optical fibers (15); and / or wherein within the diffusion chamber (14) ends a connector in which a plurality of emission terminations (15 A) of respective optical fibers (15) such as at least two emission terminations (15 A) of respective optical fibers (15), or at least four emission terminations (15 A) of respective optical fibers (15), or still at least six emission terminations (15 A) of respective optical fibers (15) converges.

6. Illumination device (10,50) according to any one of the preceding claims, wherein within the diffusion chamber (14) there is comprised at least one balancing light source (16), preferably at least one solid-state light-emitting device, such as an LED or a plurality of LEDs of different colors.

7. Illumination device (10,50) according to any one of the preceding claims, wherein the secondary collimating optic (33) is configured to generate the collimated light (34) with chromatic components with different angular distributions having a light intensity profile, referred to the semi section plane (X), characterized by an average value, calculated with reference to an attenuation angular range between an angle of attenuation (y) and 90°, lower than the average value of the light intensity profile of the light with chromatic components with different angular distributions (24), calculated with respect to the same attenuation angular range, preferably less than 60%, more preferably less than 40%, even more preferably less than 20%, wherein the angle of attenuation (y) is measured with respect to the propagation direction (A) and the attenuation angular range is a non-zero angular range, such as for example an angular range of at least 5°, preferably of at least 10°, more preferably of at least 15°, and / or secondary collimating optic (33) is configured to32AMENDED SHEET (ARTICLE 19)(i) substantially not to intercept the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25) at angles less than the first angular aperture (a), in particular to intercept less than 10% of the total flux of the light with chromatic components with different angular distributions (24) exiting from the first emitting surface (25) at angles less than the first angular aperture (a), preferably less than 5%, more preferably less than 2% and / or(ii) interact with the light with chromatic components with different angular distributions (24) in such a way as to substantially not increase the luminous flux at angles greater than the first angular aperture (a), in particular to increase the luminous flux of light with chromatic components with different angular distributions (24) exiting from the first emitting surface (25) at angles greater than the first angular aperture (a) by less than 10%, preferably less than 5%, more preferably less than 2%; and / or(iii) interact with the light with chromatic components with different angular distributions (24) in such a way as to substantially not decrease the luminous flux at angles less than the first angular aperture (a), in particular to decrease the luminous flux of light with chromatic components with different angular distributions (24) exiting from the first emitting surface (25) at angles less than the first angular aperture (a) less than 10%, preferably less than 5%, more preferably less than 2%.

8. Illumination device (10,50) according to any one of the preceding claims, wherein the secondary collimating optic (33) is made in the shape of a reflection optic configured in such a way as to intercept and reflect the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25) at angles higher than the cut-off angle (T); and / or wherein the secondary collimating optic (33) is made in the shape of a refractive lens configured to intercept and redirect the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25) at angles higher than the cut-off angle (T); and / or wherein the secondary collimating optic (33) is a structure comprising walls having at least a portion made of a material with a diffuse reflectance of at least 50%, preferably of at least 55%, more preferably of at least 60%; and / or33AMENDED SHEET (ARTICLE 19)wherein the secondary collimating optic (33) is a structure comprising walls having at least a portion made of a material with an absorption coefficient in the visible equal to at least 70%, preferably equal to at least 80%, more preferably equal to at least 90% of the incident light and positioned so as to intercept and absorb at least part of the light with chromatic components with different angular distributions (24) emitted from the first emitting surface (25) at angles higher than the cut-off angle (T).

9. Illumination system (100) comprising- at least one illumination device (10,50) for simulating natural illumination according to any one of the preceding claims, and- a sunlight collection system (40) comprising at least one collector element (17) associated with at least one optical fiber (15) whose emission termination (15 A) ends inside the diffusion chamber (14) of the at least one illumination device (10,50).

10. Illumination system (100) of claim 9, comprising a plurality of collector elements (17), wherein each collector element (17) of the plurality of collector elements (17) comprises a sunlight input surface having a surface area, wherein a set of collector elements (17) of the plurality of collector elements (17) associated with an illumination device (10,50) defines a sunlight collection surface given by a sum of the surface areas of each collector element (17) defining the set of collector elements (17); and wherein the first emitting surface (25) of the first optical unit (20) of the illumination device (10,50) associated with the set of collector elements (17) covers an area less than 50 times, preferably less than 10 times, or even more preferably less than 5 times, or even more preferably less than 1 time, e.g. equal to 0.2 times the sunlight collection surface given by the set of collector elements (17).34AMENDED SHEET (ARTICLE 19)

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