Lighting device simulating natural light

Abstract

The present invention relates generally to a lighting device simulating natural lighting, which is capable of generating at least two light components having different angular distributions and having different correlated color temperatures or CCTs. The lighting device simulating natural lighting thus conceived is capable of generating light of two chromatic components having different angular distributions, effectively preventing the light of higher color temperature (blue light) from producing a glare effect or an unnatural color of the environment that the natural light of the sky and the sun would not produce.

Description

Technical Field

[0001] This invention generally relates to an illumination device that simulates natural lighting, specifically, simulating the light of the sky and the sun, thereby generating at least two light components with different angular distributions and different correlated color temperatures (CCTs). In particular, this invention relates to an illumination device capable of generating a first highly collimated light component whose CCT is smaller than that of a second weakly collimated light component, i.e., the angular aperture of its intensity distribution is larger than that of the highly collimated light component. Background Technology

[0002] As is well known, state-of-the-art lighting systems are capable of simulating natural lighting, especially the light from the sky and the sun, and can produce light with chromaticity components that have different angular distributions, including a first component of directional or direct light with a first correlated color temperature or a low CCT, and a second component of diffuse light with a large CCT.

[0003] Exemplary embodiments of such lighting systems using, for example, Rayleigh-like diffusers are described in several patent applications filed by the same applicant, such as WO 2009 / 156347 A1, WO 2009 / 156348A1, WO 2014 / 076656A1, and WO 2017 / 0847561A1. Most known lighting systems use a light source capable of producing visible light, 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 incident light in a manner similar to the Earth's atmosphere under clear sky conditions, thereby separating the incident light into a first portion of direct light that passes through the panel and a second portion of light that is diffused by the panel, which is essentially not diffused. In particular, the diffused light component has a larger CCT than the direct light component because the scattering efficiency of a Rayleigh-like diffuser is a function of the wavelength of light, and the scattering efficiency is higher for shorter wavelengths.

[0004] Because of the interaction between the direct components that illuminate objects and cast their shadows with light having a lower CCT and diffuse light that makes the shadows appear blue, the lighting system is able to reproduce solar lighting, thus giving the environment a sense of spaciousness.

[0005] However, this effect is significantly reduced when known lighting systems that simulate natural lighting are used in conjunction with secondary lighting devices that produce conventional white light in an environment. The purpose of adding secondary lighting devices is usually to achieve illuminance higher than that provided by natural lighting systems alone, thereby keeping the overall cost of the lighting environment under control.

[0006] In this situation, because traditional secondary lighting cannot produce the intensity and color contrast unique to natural light, the spatial expansion effect provided by lighting systems that simulate natural light is practically imperceptible.

[0007] Therefore, the applicant believes that it is convenient to use secondary lighting devices in order not to change the feeling provided by the lighting system that simulates natural light. These devices are also able to produce light with different angular distributions, and the angular apertures of their chromaticity characteristics and intensity distributions are comparable to the light components produced by the lighting system that simulates natural light.

[0008] Therefore, the applicant's goal is to design a lighting device that simulates natural light, which can be used as a secondary lighting device in conjunction with a lighting system that simulates natural light.

[0009] Specifically, the applicant's goal is to develop a lighting device that simulates natural lighting, which can increase the overall illuminance provided by a natural lighting system without altering the perceived brightness, and can be achieved at a reasonable cost.

[0010] In addition, the applicant's goal is to design a lighting device that simulates natural lighting, which can be used to achieve localized natural lighting, such as illuminating a limited area, such as a workbench, desk, table, etc.

[0011] Specifically, the applicant wishes to study a lighting device that simulates natural light, which can reproduce natural light without producing glare or unnatural colors on the ceiling of the room in which the device is installed, while providing high lighting efficiency. Summary of the Invention

[0012] In a first aspect, the present invention relates to a lighting device simulating natural lighting, the device comprising, in sequence, a first optical unit, the first optical unit comprising, in sequence, a main light source configured to emit main light in the visible spectrum, a dichroic separating optics configured to intercept at least a portion of the main light generated by the main light source, and to emit from a first emitting surface at least one highly collimated light component having a propagation direction originating from the main light source and at least one diffuse light component. The at least one highly collimated light component and the at least one diffuse light component form light with chromaticity components having different angular distributions.

[0013] Furthermore, at least one first highly collimated light component has a first correlated color temperature (CCT1), total flux, and luminous intensity distribution, characterized in that, measured by half-width maximum (HWHM) of at least one half-plane section of a dichroic separating optics containing the propagation direction, the first corner aperture α is less than 30°.

[0014] Similarly, at least one diffuse light component has a second correlated color temperature (CCT2) higher than the first correlated color temperature (CCT1), and a non-zero luminous intensity distribution with an angle twice larger than the first angular aperture α, for example, essentially a Lambertian luminous intensity distribution.

[0015] Basically, a Lambert emission distribution can be understood as an emission distribution that is proportional to the cosine of the emission angle. For the normal direction of the emission surface, the emission angle is equal to 0°.

[0016] According to the invention, a second optical unit is also provided, the unit comprising a second-order collimating optics configured to at least intercept a portion of light emitted from the first emitting surface having chromaticity components with different angular distributions, and to generate light starting from the light having chromaticity components with different angular distributions.

[0017] -A reference half-plane cross-section has a light component whose luminous intensity distribution is not a weakly collimated light component. This component is characterized by, calculated within the attenuation angle range between a reference attenuation angle γ and 90°, having an average luminous intensity distribution of the weakly collimated light component that is less than the average luminous intensity distribution of at least one diffuse light component. Within the same attenuation angle range, the attenuation angle γ is measured relative to the propagation direction and is at least twice the first angular aperture α of the luminous intensity distribution of the first highly collimated light component emitted from the first emitting surface.

[0018] - The second highly collimated light component has a total flux that is substantially the same as that of the first highly collimated light component, and the second luminous intensity distribution aperture α' is less than or equal to the first luminous intensity distribution aperture α of the first highly collimated light component emitted from the first emitting surface; and

[0019] The weakly collimated light component and the second highly collimated light component form collimated light with chromaticity components having different angular distributions emitted by the second optical unit.

[0020] This type of lighting device, designed to simulate natural lighting, produces light with two chromaticity components distributed at different angles. This effectively prevents glare from higher color temperature light (blue light) or creates unnatural colors in the environment that are not produced by natural light from the sky and the sun. At the same time, the lighting efficiency remains essentially unchanged.

[0021] Thus, the lighting device according to the invention can be effectively used as a secondary lighting device to support lighting systems that simulate natural lighting, since the generation of chromaticity components with different angular distributions can support the reproduction of natural lighting effects by these systems, and can also be used as local natural lighting, providing good lighting efficiency without glare effects.

[0022] According to a second aspect, the present invention relates to a lighting system for simulating natural lighting, comprising a plurality of lighting devices of the type described above, which are arranged in a manner that produces a plurality of highly collimated light components, each surrounding a corresponding propagation direction of a plurality of parallel propagation directions, the lighting devices being arranged in an extended structure on a plane perpendicular to each propagation direction.

[0023] Advantageously, such a lighting system makes it possible to achieve the same advantages as described in the lighting device for simulating natural lighting of the present invention.

[0024] The present invention has at least one of the following preferred features; in particular, the latter can be combined with each other as needed to meet specific application requirements.

[0025] Preferably, at least one first height-collimated light component has a luminous intensity distribution, characterized in that the first angular aperture α, measured by half-width maximum (HWHM) of at least one half-plane section of the dichroic separating optics including the propagation direction, is less than 20°, more preferably less than 15°.

[0026] Preferably, the attenuation angle γ is at least 2.5 times the first angular aperture α of the luminous intensity distribution of the first highly collimated light component emitted by the first emitting surface, and more preferably 3 times it.

[0027] In one variation of the invention, the secondary collimating optics is configured to generate a weakly collimated light component with a luminous intensity distribution, the reference half-plane section, characterized in that its average value is less than 60%, preferably less than 40%, and more preferably less than 20%, of the luminous intensity distribution of at least one diffuse light component calculated from the reference attenuation angle range.

[0028] The secondary collimating optics are further preferably configured to substantially not intercept the highly collimated light component and / or not redistribute and / or redirect the highly collimated light component outside the first angular aperture α, particularly intercepting and / or redistributing and / or redirecting the highly collimated light component outside the first angular aperture α, such that the total flux of the highly collimated light component emitted from the first emitting surface 25 is less than 10%. Preferably less than 5%, most preferably less than 2%.

[0029] In one variation of the invention, the secondary collimating optics are embodied as a refractive lens configured to intercept and reflect at least a portion of at least one diffuse light component and redistribute it to produce a weakly collimated light component with a luminous intensity distribution, referring to a half-plane section, characterized in that its average value is less than the average value of the luminous intensity distribution of at least one diffuse light component calculated over the attenuation angle range.

[0030] Alternatively or additionally, the secondary collimating optics are embodied as a refractive lens configured to intercept and redirect at least part of at least one diffuse light component and redistribute it in order to produce a weakly collimated light component with a luminous intensity distribution, referring to a half-plane section, characterized in that the average value is less than the average value of the luminous intensity distribution of at least one diffuse light component calculated over the attenuation angle range.

[0031] Preferably, the refractive lens is configured to additionally intercept and redirect at least part of the first height-collimated light component in order to produce a second height-collimated light component with a luminous intensity distribution, characterized in that, with reference to the half-plane section, the second angular aperture α' measured by the maximum half-width (HWHM) is less than or equal to, preferably less than, the first angular aperture α.

[0032] Alternatively or additionally, the structure of a secondary collimating optics includes a wall having at least a portion made of a material with a diffraction rate of at least 50%, preferably at least 55%, more preferably at least 60%.

[0033] Alternatively or additionally, the structure of the secondary collimating optics includes at least a portion of a wall made of a material having an absorption coefficient of at least 70%, more preferably at least 80%, and most preferably at least 90% of the incident light in the visible range, positioned to intercept and absorb at least a portion of the diffuse light component emitted from the first emitting surface at an angle greater than the attenuation angle γ.

[0034] In this description and the following claims, the terms “absorption coefficient,” “normal reflectance,” and “diffuse reflectance” are as defined in standard E284 for terms describing the appearance of materials and light sources.

[0035] Preferably, the secondary collimating optics are configured to substantially not modify the correlated color temperature (CCT) of the light components having chromaticity components emitted by the first optical unit with different angular distributions.

[0036] Preferably, the secondary collimating optics is configured to generate a weakly collimated light component, whose correlated color temperature is substantially equal to the second correlated color temperature CCT2 of the diffuse light component emitted from the first emitting surface, starting from light with chromaticity components having different angular distributions emitted from the first emitting surface, and a second highly collimated light component, whose correlated color temperature is substantially equal to the first correlated color temperature CCT1 of the first highly collimated light component emitted from the first emitting surface.

[0037] In one variation of the invention, referring to a half-plane section, the angular aperture β of the weak collimated light component, measured by the maximum half-width (HWHM) of the luminous intensity distribution, is 1.2 times larger than the first angular aperture α of the first highly collimated light component, preferably 1.5 times, and more preferably 2 times, than the maximum half-width (HWHM) of the luminous intensity distribution.

[0038] In one variation of the invention, the dichroic separation optics includes a primary collimating optical element configured to generate a highly collimated light component with a first angular aperture α luminous intensity distribution starting from the primary light, and a diffuse light generator configured to generate a diffuse light component with a second correlated color temperature.

[0039] Preferably, the diffuse light generator is a dispersive element configured such that at least one first spectral portion of the light incident on the element is transparent and at least one second spectral portion of the incident light is scattered.

[0040] Alternatively or additionally, the diffuse light generator is a tunable type of dispersive element configured to primarily change the scattering efficiency of the color scattering element in at least the second spectral portion of the incident light, thereby tuning the scattering efficiency of the second spectral portion of the incident light.

[0041] Alternatively or additionally, the diffuse light generator is a tunable dispersive element comprising a substrate made of a polymer material in which liquid crystal nanodroplets are trapped.

[0042] Alternatively or additionally, a diffuse light generator is a dispersive element in the shape of a panel, thin film, surface coating, or surface anodized layer.

[0043] Alternatively or additionally, the diffuse light generator is an active diffuse light generator capable of producing diffuse light independently of the main light source, and is made of a material that is substantially transparent to light, regardless of its spectrum.

[0044] More preferably, the dispersive element is placed on the first emitting surface, or at least on an interaction surface between the main beam and the main collimating element.

[0045] In one variation of the invention, at least the main collimating optical element of the dichroic separation optics has axial symmetry, and the propagation direction is contained on the axis of symmetry of the main collimating optical element; and the diffuse light generator has a circular or quadrilateral cross section, such as a square, rectangular or polygonal cross section.

[0046] In another variation of the invention, the optical element for primary collimation of the dichroic separation optics has an elongated structure transverse to the propagation axis along the extension axis of the device.

[0047] In one variation of the invention, the first optical unit includes a plurality of main light sources, for example, arranged side by side and / or aligned along an extension axis, wherein the dichroic separating optics includes at least one collimating lens associated with the plurality of main light sources and is configured to collimate the light emitted by each main light source along a corresponding propagation direction of a plurality of parallel propagation directions. Attached Figure Description

[0048] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the specification, serve to explain the principles of the invention.

[0049] in:

[0050] Figure 1This is a schematic diagram of a first embodiment of a lighting device that simulates natural lighting according to the present invention.

[0051] Figure 2 This is a schematic diagram of a second embodiment of a lighting device for simulating natural lighting according to the present invention.

[0052] Figure 3 This is a schematic diagram of a third embodiment of a lighting device for simulating natural light according to the present invention.

[0053] Figure 4 This is a schematic diagram of a fourth embodiment of a lighting device for simulating natural light according to the present invention.

[0054] Figure 5 This is a schematic diagram of a fifth embodiment of a lighting device for simulating natural light according to the present invention.

[0055] Figure 6 This is a schematic diagram of a sixth embodiment of a lighting device for simulating natural light according to the present invention.

[0056] Figure 7 This is a schematic diagram of a seventh embodiment of a lighting device for simulating natural light according to the present invention; and

[0057] Figure 8 This is a schematic diagram of an embodiment of a lighting system that simulates natural lighting, consisting of multiple lighting devices, according to the present invention. Detailed Implementation

[0058] The following is a detailed description of exemplary embodiments of the present invention. The exemplary embodiments described herein and illustrated in the accompanying drawings are intended to teach the principles of the invention, enabling those skilled in the art to implement and use the invention in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended and should not be considered as a limiting description of the scope of patent protection. Rather, the scope of patent protection should be defined by the appended claims.

[0059] refer to Figure 1 The illustration schematically depicts a lighting device simulating natural light according to a first embodiment of the present invention, hereinafter referred to as the "lighting device" or simply 10 for the sake of brevity.

[0060] The lighting device 10 includes a first optical unit 20 and a second optical unit 30 optically coupled to each other, such that the second optical unit 30 intercepts at least a portion of the light emitted by the first optical unit 20.

[0061] Specifically, the first optical unit 20 includes at least one main light source 21 configured to emit a main light 22, the main light 22 comprising at least one set of electromagnetic radiation with wavelengths contained in the visible spectrum (i.e., 380 nm ≤ λ ≤ 740 nm), hereinafter referred to as "beam", "ray", or "light". For example, the main light source 21 is a solid-state light-emitting device (LED).

[0062] The first optical unit 20 further includes a dichroic separating optical device 23 having at least a first emitting surface 25, from which light 24 emitted has chromaticity components with different angular distributions. The main light source 21 is positioned to substantially introduce the main light 22 into the dichroic separating optical device 23.

[0063] The dichroic separating optics 23 is configured to, starting from the main light 22 emitted from the main light source 21, generate at least one first highly collimated light component 24a that passes through the first emitting surface 25 and propagates in the propagation direction A, the propagation direction A of which coincides with the direction in which the first highly collimated light component 24a exhibits maximum luminous intensity; and to generate a diffuse light component 24b that passes through the first emitting surface 25 and propagates in substantially all directions. For example, the diffuse light component 24b has a substantially Lambertian luminous intensity distribution.

[0064] The first highly collimated light component 24a generated by the dichroic separating optics 23 is characterized by having a luminous intensity distribution, measured with half-width at most (HWHM) of at least one half-plane section X of the dichroic separating optics 23 including the propagation direction A, wherein the angular aperture α of the luminous intensity distribution is less than 30°, preferably less than 20°, and more preferably less than 15°. Furthermore, the first highly collimated light component 24a is characterized by having a first correlated color temperature or CCT1 and total flux.

[0065] The dichroic separation optics 23 is further configured to generate at least one diffuse light component 24b having a second correlated color temperature or a different CCT2, particularly higher than the correlated color temperature CCT1 of the first highly collimated light component 24a. Specifically, the correlated color temperature CCT1 of the first highly collimated light component 24a is 1.2 times lower than the correlated color temperature CCT2 of the diffuse light component 24b, preferably 1.3 times lower, and more preferably 1.4 times lower.

[0066] In exemplary terminology, the dichroic separating optics 23 includes a primary collimating optical element 23a, such as... Figure 1 The total internal reflection (TIR) ​​lens shown, or as... Figure 2 The reflector shown, and the diffuse light generators 23b, 23b', and 23b', are in Figure 1In this embodiment, a dispersive element 23b is fabricated and placed on the first emitting surface 25 to intercept collimated light emitted from the main collimating optical element 23a. Specifically, Figure 1 In this embodiment, the primary collimating optical element 23a has axial symmetry, such that the luminous intensity distribution of the first highly collimated light component 24a is substantially equal to the half-plane cross-section X of the dichroic separating optical device 23 containing the propagation direction A. The chromatic scattering element 23b can also be implemented through axial symmetry, for example, through a circular cross-section, or without axial symmetry but with a quadrilateral cross-section, such as a square or rectangle, or a regular or irregular polygonal cross-section.

[0067] A "chromatic diffusion element" is a diffusion element whose light diffusion characteristics depend on the wavelength of the light passing through it, such as a Rayleigh diffuser or a Rayleigh-like diffuser. This type of diffuser is characterized by being substantially transparent to the first spectral portion of the light incident upon it, or having negligible interaction with the first spectral portion.

[0068] Therefore, the first spectral portion of the incident light passes through the color scattering element 23b with essentially no change and is collimated by the principal collimating optical element 23a. Downstream of the color scattering element 23b, a first highly collimated light component 24a of light 24 is generated. This light component 24a has a different angular distribution and a lower correlated color temperature CCT1, where "downstream" is relative to the propagation direction A. Conversely, the dispersing element 23b primarily acts on the second spectral portion of the incident light, significantly scattering it, thereby generating a diffuse light component 24b of light 24 with a different angular distribution. Because it essentially contains no wavelengths belonging to the first spectral portion, it has a higher correlated color temperature CCT2.

[0069] Color difference separation and the generation of diffuse light component 24b with a high CCT2 (blue light component) can be achieved by using, for example... Figure 1 This can be achieved using either a "thick" panel or a "thin" layer. Figure 5 The terminology used in the example, and is generally referred to herein as “color scattering element 23b”, comprises a layer in the host material in which transparent nano-scattering elements (also called “scattering elements”) are present in a predetermined number per unit area and have different refractive indices relative to the refractive index of the host material.

[0070] Such dispersive elements can be in the form of panels, thin films, surface coatings, or even surface anodized layers on metal surfaces. Their specific structural features are described in detail in Italian patent application No. 1020200008113 filed by the same applicant, the contents of which are fully cited and incorporated herein by reference.

[0071] Similarly, the dispersive element can be tunable, thereby allowing tuning of the interaction strength between the dispersive element and the incident light, thus altering the diffusion efficiency, particularly the second spectral portion of the incident light, i.e., the portion of the incident light where the dispersive element primarily functions. Tunable chromatic diffusion elements include, for example, a matrix made of a polymer material (host material) in which so-called nanodroplets (diffusion nanoelements) containing liquid crystal (LC) molecules are trapped. The liquid crystals cause anisotropy in the refractive index, thus the jump in refractive index between the liquid crystal nanodroplets and the host material can be adjusted by changing the applied voltage. Generally, the change in refractive index is due to the tendency of the liquid crystal molecules within each nanodroplet to align when an electric field is applied, and the degree of alignment can be varied depending on the magnitude of the applied voltage. For further details, please refer to International Patent Application No. WO 2018 / 091150 of the same applicant, the full contents of which are incorporated herein by reference.

[0072] and Figure 1 The implementation methods are different. Figure 2 The illustrated embodiment includes an active diffuse light generator 23b', capable of generating diffuse light independently of the main light source 21, placed on the first emitting surface 25. Specifically, the diffuse light generator 23b' generates a diffuse light component 24b with a correlated color temperature (CCT2) higher than that of the light 24 emitted from the first emitting surface 25, which has a different angular distribution of chromaticity components. Furthermore, the diffuse light generator 23b' is made of a material that is substantially transparent to light and is independent of its spectrum. Thus, almost all the collimated light emitted from the main collimating optical element 23a is intercepted by the diffuse light generator 23b' and propagates downstream relative to the propagation direction A, generating a first highly collimated light component 24a of the light 24 emitted from the first emitting surface 25, which has a different angular distribution of chromaticity components.

[0073] The second optical unit 30 includes at least one secondary collimating optical device 33, which has a light input surface 36 positioned downstream of the first emitting surface 25 of the first optical unit 20, thereby intercepting at least a portion of the light 24 emitted by the first optical unit 20 with different angular distributions of chromaticity components. The secondary collimating optical device 33 also has a second emitting surface 35 from which collimated light 34 with different angular distributions of chromaticity components is emitted.

[0074] In particular, the secondary collimating optics 33 is configured to interact with the diffuse light component 24b of the light 24 emitted by the first optical unit 20, so as to generate a weak collimated light component 34b downstream of the second emitting surface 35 having an luminous intensity distribution with reference to at least one half-plane cross section X of the dichroic separating optics 23. The weak collimated light component 34b is characterized by having an average value less than the average value of the luminous intensity distribution of at least one diffuse light component 24b calculated with reference to the attenuation angle range consisting of attenuation angle γ and 90°.

[0075] Specifically, the attenuation angle γ is measured relative to the propagation direction A and is equal to at least 2 times, preferably at least 2.5 times, and even more preferably at least 3 times, the first angular aperture α of the luminous intensity distribution of the first highly collimated light component 24a emitted by the first emitting surface 25.

[0076] For example, the secondary collimating optics 33 is configured to generate a weak collimated light component 34b. Referring to the half-plane section X, the luminous intensity distribution of the weak collimated light component 34b is characterized by an average luminous intensity distribution of the diffuse light component 24b emitted from the first emitting surface 25, calculated within the attenuation angle range, i.e., the angle range comprised of the attenuation angle γ and 90°, being less than 60%, preferably less than 40%, and more preferably less than 20%. This ensures that the illumination device 10, within the attenuation angle range and referring to at least one half-plane section X, possesses minimal glare while maintaining high luminous efficiency.

[0077] Furthermore, the secondary collimating optics 33 is configured to interact with the first highly collimated light component 24a of the light 24 emitted from the first emitting surface 25 to generate a second highly collimated light component 34a, the total flux of which is substantially the same as that of the first highly collimated light component 24a. The second angular aperture α' of the luminous intensity distribution of this light component 34a is equal to or smaller than the first angular aperture α of the luminous intensity distribution of the first highly collimated light component 24a emitted from the first emitting surface 25. For example, by not intercepting the first highly collimated light component 24a, such as... Figure 1-3 As shown, either by not redistributing the first height-collimated light component 24 or by redirecting the first height-collimated light component 24 outside its angular aperture α, as Figure 4 As shown. In other words, the secondary collimating optics 33 is configured to substantially maintain or at most reduce the luminous intensity distribution of the first highly collimated light component 24a, while substantially not changing its total flux. For example, the secondary collimating optics 33 is configured to attenuate the total flux of the first highly collimated light component 24a emitted from the first emitting surface 25 by 10%, preferably less than 5%, more preferably less than 2%.

[0078] Furthermore, the secondary collimating optics 33 is configured to substantially not modify the correlated color temperature (CCT) of the light components 24 emitted by the first optical unit 20, which have chromaticity components with different angular distributions. Therefore, at the exit of the second emitting surface 35, a weakly collimated light component 34b is generated, whose correlated color temperature is substantially equal to the second correlated color temperature (CCT2) of the diffuse light component 24b of the light 24 emitted by the first optical unit 20; and a second highly collimated light component 34a, whose correlated color temperature is substantially equal to the first correlated color temperature (CCT1) of the first highly collimated light component 24a of the light 24 emitted by the first emitting surface 25. The combination of these light components 34a and 34b forms collimated light 34 emitted by the second emitting surface 35 of the second optical unit 30, which has chromaticity components with different angular distributions.

[0079] In particular, the weak collimated light component 34b is characterized by an luminous intensity distribution with an angular aperture α' that has an intensity distribution with an angular aperture β greater than that of the second height collimated light component 34a, wherein both intensity distributions are referenced to at least one half-plane section X of the dichroic separation optics 23.

[0080] For example, the maximum half-width (HWHM) of the angular aperture β of the weak collimated light component 34b is 1.2 times larger than the maximum half-width (HWHM) of the angular aperture α' of the intensity distribution of the second height collimated light component 34a, preferably 1.5 times larger, and most preferably 2 times larger.

[0081] exist Figure 1 and Figure 2 In this embodiment, the secondary collimating optics 33 is a structure composed of internally opaque walls, positioned to diffusely reflect at least a portion of the diffuse light component 24b emitted at an angle greater than the attenuation angle γ. For this purpose, the diffuse reflectance of the material constituting these walls is at least 50%, preferably at least 55%, and more preferably at least 60%.

[0082] Reference Figure 3 This schematically illustrates a different embodiment of the lighting device 10. In particular, Figure 3 The embodiments differ from the first embodiment in the implementation of the dichroic separation optics 23 and the secondary collimating optics 33.

[0083] exist Figure 3In this embodiment, the dichroic separation optics 23 includes an active diffuse light generator 23b'. Furthermore, the secondary collimating optics 33 is made into a reflector, thus forming an internal reflective wall, and is configured to intercept and reflect at least a portion of the diffuse light component 24b, and redistribute the diffuse light component 24b to attenuate the diffuse light component 24b above the attenuation angle γ (measured relative to the propagation direction A, and equal to at least 2 times, preferably 2.5 times, more preferably 3 times the angular aperture α of the luminous intensity distribution of the first highly collimated light component 24a) with reference to at least one half-plane cross section X. Therefore, the material constituting the inner wall has a regular reflectivity of at least 60%, preferably at least 65%, more preferably at least 70%. Furthermore, the secondary collimating optics 33 is configured not to intercept the first highly collimated light component 24a emitted by the first emitting surface 25.

[0084] Reference Figure 4 This illustrates, schematically, another embodiment of the lighting device 10 according to the present invention. In particular, Figure 4 The embodiments differ from the prior embodiments in the implementation of the secondary collimating optics 33.

[0085] In detail, Figure 4 In this embodiment, the secondary collimating optics 33, embodied as a refractive lens, is configured to interact with the diffuse light component 24b emitted from the first emitting surface 25 of the first optical unit 20 to reduce the luminous intensity at angles above the attenuation angle γ of at least one half-plane section X. Thus, a weakly collimated light component 34b is generated downstream of the second emitting surface 35, having an average value of the luminous intensity distribution calculated over an angle between the attenuation angle γ and 90°, which is less than the average value calculated over the same angular range of the luminous intensity distribution of the diffuse light component 24b.

[0086] Furthermore, the secondary collimating optics 33 is configured to further collimate the first highly collimated light component 24a emitted from the first emitting surface 25, thereby obtaining a second highly collimated light component 34a downstream of the second emitting surface 35. This light component has a second angular aperture α' of the luminous intensity distribution, which is smaller than the first angular aperture α of the luminous intensity distribution of the first highly collimated light component 24a emitted from the first emitting surface 25. In other words, the secondary collimating optics 33 is configured to generate a second highly collimated light component 34a starting from the first highly collimated light component 24a emitted from the first emitting surface 25, while maintaining its total flux substantially unchanged and reducing the angular aperture of the luminous intensity distribution on the reference half-plane.

[0087] Therefore, at the exit of the second emitting surface 35, there is a weakly collimated light component 34b with a higher correlated color temperature (CCT2) and a second highly collimated light component 34a with a lower correlated color temperature (CCT1). The latter is characterized by a second angular aperture α' of its luminous intensity distribution being smaller than the first angular aperture α of the luminous intensity distribution of the first highly collimated light component 24a emanating from the first optical unit 20, and its total flux being substantially equal to the total flux of the first highly collimated light component 24a. The combination of light components 34a and 34b forms the collimated light 34 emitted from the second emitting surface 35 of the second optical unit 30.

[0088] Reference Figure 5 This illustrates, schematically, another embodiment of the lighting device 10 according to the present invention. In particular, Figure 5 The embodiment differs from other embodiments in that the dichroic separating optics 23 is fabricated as a reflector 23a, the walls of which interact with the incident light emitted from the main light source 21; that is, the inner reflective wall is covered by a layer 23b” made of a chromaticity diffusing material. For example, if the material constituting the chromaticity diffusing layer 23b” is a liquid crystal type, it is used by lamination. Alternatively, for example, the layer is grown directly on the inner wall of the reflector 23a as an anodized layer.

[0089] In this configuration, the light 22 emitted by the main light source 21 is incident on the inner wall of the reflector 23a, where it is partially collimated and partially diffused. Specifically, the first spectral portion of the incident light passes through the dispersive layer 23b” twice (the incident beam and the reflected beam) in a substantially unchanged manner, thus undergoing almost complete collimation caused by the reflector 23a. Conversely, the second spectral portion of the incident light interacts significantly with the dispersive layer 23b” covering the inner wall of the reflector 23a, primarily through scattering.

[0090] This results in two chromaticity components with different angular distributions from the dichroic separation optics 23: a first highly collimated light component 24a with a lower correlated color temperature CCT1 and a diffuse light component 24b with a higher correlated color temperature CCT2.

[0091] To ensure that almost all of the second spectral portion of the emitted main light 22 interacts with the dispersive layer 23b” to produce the diffuse light component 24b, the illumination device 10 may include a screen 27 located downstream of the main light source 21 relative to the propagation direction A, so as to block the direct emission of light emitted by the main light source 21 through the first emitting surface 25.

[0092] Figure 6 Another embodiment of the lighting device 10 according to the invention is shown, wherein the dichroic separation optics 23 is embodied as a TIR lens, and part of the light enters the surface 26 coated with the chromatic scattering layer 23b”.

[0093] In this case, the light 22 emitted by the main light source 21, passing through the portion entering the surface 26, is partially collimated and partially diffused. In particular, the first spectral portion of the light passing through the portion entering the surface 26—and therefore also through the dispersive layer 23b”—remains essentially unchanged, thus undergoing the collimation provided by the lens 23a. Conversely, the second spectral portion of the light incident on the dispersive layer 23b” interacts significantly with the dispersive layer 23b” and is primarily scattered.

[0094] This results in two chromaticity components with different angular distributions emerging from the dichroic separation optics 23: a first highly collimated light component 24a with a lower correlated color temperature CCT1 and a diffuse light component 24b with a higher correlated color temperature CCT2.

[0095] In addition, Figure 6 In this embodiment, the secondary collimating optics 33 is fabricated to include an internal absorbing (dark) wall positioned to absorb at least a portion of the diffuse light component 24b emitted at an angle greater than the attenuation angle γ, with reference to at least one half-plane cross-section X. For this purpose, the material of the wall has an absorption coefficient in the visible light range of at least 70%, more preferably 80%, and even more preferably 90% of the light incident thereon.

[0096] Reference Figure 7 This demonstrates yet another embodiment of the lighting device 10' according to the present invention, presenting a perpendicular to Figure 7 A slender extension of the plane.

[0097] In detail, Figure 7 The first optical unit 20 of the device includes a plurality of main light sources 21, preferably arranged side by side and along the elongated direction of the device 10', and a dichroic separating optics 23 including at least one collimating optical component 23a associated with the plurality of main light sources 21, and configured to collimate the light emitted by the plurality of main light sources 21 around a plurality of propagation directions A, each propagation direction being associated with and intersecting the respective main light source 21 among the plurality of main light sources, so as to generate a first highly collimated light component 24a in at least a plurality of parallel half-plane sections X of the dichroic separating optics 23, each first highly collimated light component 24a including one of the plurality of parallel propagation directions A, and a diffuse light generator 23b' is configured to generate a diffuse light component 24b with a correlated color temperature CCT2 that is different from or even higher than the correlated color temperature CCT1 of the first highly collimated light component 24a.

[0098] The first highly collimated light component 24a generated by the dichroic separating optical device 23 is characterized in that, with reference to at least one half-plane section X of the dichroic separating optical device 23 containing the propagation direction A, the angular aperture α of its luminous intensity distribution is less than 30°, preferably less than 20°, and more preferably less than 15°.

[0099] The elongated, non-axially symmetrical arrangement of the illumination device 10' is primarily due to the fact that the first highly collimated light component 24a generated by the dichroic separating optics 23 has an luminous intensity distribution with an angular aperture less than or equal to 30° (20° or 15° respectively) relative to a subset of the half-plane cross-section X of the dichroic separating optics 23 containing the propagation direction A, and is tilted relative to each other about the propagation direction A. In particular, the subset of the half-plane cross-section X satisfying this condition comprises half-planes tilted relative to each other within an angle range of at least 20°.

[0100] Figure 7 The second optical unit 30 includes a second-order collimating optics 33, which is made into a reflective, opaque, and / or absorptive screen, positioned to intercept only the diffuse light component 24b of the light 24 emitted by the first optical unit 20. The second-order collimating optics 33 attenuates the luminous intensity of the diffuse light component 24b above the attenuation angle γ at at least one half-plane section X of the dichroic separating optics 23. Thus, referring to... Figure 7 The specific installation of the central lighting fixture 10' makes it possible to reproduce the effect of natural lighting and prevent the pale blue diffuse light component 24b from being unnaturally projected onto the ceiling.

[0101] Furthermore, in order to keep the first height-collimated light component 24a emitted by the first optical unit 20 substantially unchanged, the second-level collimating optics 33 is configured to substantially not change or at most reduce the angular aperture α of the luminous intensity distribution and not modify the total flux.

[0102] Therefore, a weakly collimated light component 34b and a highly collimated light component 34a are generated from the second emitting surface 35, which form collimated light 34 emitted by the second optical unit 30, thereby exiting from the lighting device 10' according to the invention. In particular, the highly collimated light component 34a emitted from the second optical unit 30 has an angular aperture α' equal to or smaller than the angular aperture α of the intensity distribution of the first highly collimated light component 24a emitted from the first optical unit 20, and its total flux is substantially equal to the total flux of the first highly collimated light component 24a.

[0103] In particular, the weak collimated light component 34b is characterized by an luminous intensity distribution with an angular aperture α' having an intensity distribution with an angular aperture β greater than that of the second height collimated light component 23a, wherein both intensity distributions are referenced to at least one half-plane section X of the dichroic separating optical device 23.

[0104] Figure 8 A lighting system 100 simulating natural lighting was demonstrated, including... Figure 2 The multiple illumination devices 10 of the type shown, in particular the principal collimating optical element 23a of the dichroic separating optics 23, have axial symmetry, and the illumination devices 10 are arranged such that the axes of symmetry of each principal collimating optical component 23a are arranged parallel to each other. Furthermore, the illumination devices 10 are arranged in an extended structure on a plane perpendicular to each axis of symmetry of the optical component 23a used for principal collimation.

[0105] Such an invention can be modified and varied in several ways, all of which fall within the scope of creating a concept. For example, the second-order collimating optics 33 can be implemented as a structure that includes an inner wall that partially absorbs and partially reflects, or is partially opaque and partially reflective, or partially opaque and partially absorbs, and in any case is configured to absorb at least a portion of the diffuse light component 24b intercepted by the optics 33 and reflect at least another portion of the diffuse light component 24b intercepted by the optics 33, so as to attenuate the luminous intensity of the diffuse light component 24b above the attenuation angle γ in at least one half-plane section X.

[0106] In short, all the details can be replaced with other technically equivalent elements.

Claims

1. A lighting device (10, 10') simulating natural lighting, comprising: The first optical unit (20) includes The main light source (21) is configured to emit a main light (22) of the visible spectrum, and The dichroic separation optical device (23) is configured to intercept at least a portion of the main light (22) generated by the main light source (21) and emit at least one first highly collimated light component (24a) with a propagation direction (A) generated from the main light (22) from the first emitting surface (25), and at least one diffuse light component (24b), the at least one first highly collimated light component (24a) and the at least one diffuse light component (24b) forming a light (24) with a chromaticity component having a different angular distribution; Among them, at least one first highly collimated light component (24a) has a first correlated color temperature (CCT1), total flux, and luminous intensity distribution, which is characterized by a first angular aperture (α) less than 30° as measured with half-width maximum (HWHM) at at least one half-plane section (X) of a dichroic separating optics (23) including the propagation direction (A), and Among them, at least one diffuse light component (24b) has a non-zero luminous intensity distribution with a second correlated color temperature (CCT2) higher than the first correlated color temperature (CCT1) and an angle higher than twice the first angular aperture (α); and The second optical unit (30), including a second-order collimating optics (33), is configured to intercept light (24) emitted from the first emitting surface (25) having at least a portion of chromaticity components with different angular distributions, and to generate light (24) with chromaticity components having different angular distributions. - A weakly collimated light component (34b) having an intensity distribution, referring to a half-plane section (X), characterized in that, calculated with reference to an attenuation angle range consisting of an attenuation angle (γ) and 90°, the average intensity of the weakly collimated light component (34b) is less than the average intensity of the intensity distribution of at least one diffuse light component (24b), calculated within the same attenuation angle range, the attenuation angle (γ) being measured relative to the propagation direction (A), and being at least twice the first angular aperture (α) of the intensity distribution of the first highly collimated light component (24a) emitted by the first emitting surface (25), and - The second highly collimated light component (34a) has a total flux that is basically the same as that of the first highly collimated light component (24a). The angular aperture (α') of the second luminous intensity distribution of the second highly collimated light component (34a) is equal to or smaller than the first angular aperture (α) of the first highly collimated light component (24a) emitted by the first emitting surface (25). The weak collimated light component (34b) and the second highly collimated light component (34a) form collimated light (34) emitted from the second optical unit (30) and having chromaticity components with different angular distributions.

2. The lighting device (10, 10') according to claim 1, wherein the secondary collimating optics (33) is configured to generate a weakly collimated light component (34b) having a luminous intensity distribution, with reference to a half-plane section (X), characterized in that, calculated with reference to the attenuation angle range, the average value of the luminous intensity distribution of the weakly collimated light component (34b) is less than 60% of the average value of the luminous intensity distribution of at least one diffuse light component (24b); and The secondary collimating optics (33) are configured to intercept and / or redistribute and / or redirect 10% of the total flux of the highly collimated light component (24a) emitted from the first emitting surface (25) outside the first angular aperture (α).

3. The lighting device (10, 10') according to claim 1 or 2. in, The secondary collimating optics (33) are made into reflective optics, configured to intercept and reflect at least a portion of the diffuse light component (24b) and redistribute the diffuse light component (24b) to produce a weakly collimated light component (34b) with a luminous intensity distribution. Referring to the half-plane section (X), the luminous intensity distribution of the weakly collimated light component (34b) is characterized by its average value being less than the average value of the luminous intensity distribution of at least one diffuse light component (24b) calculated relative to the attenuation angle range; and / or The secondary collimating optics (33) is embodied as a refractive lens, configured to intercept and redirect at least a portion of at least one diffuse light component (24b) and redistribute the diffuse light component (24b) to produce a weakly collimated light component (34b) with a luminous intensity distribution. Referring to the half-plane section (X), the luminous intensity distribution of the weakly collimated light component (34b) is characterized by its average value being less than the average value of the luminous intensity distribution of at least one diffuse light component (24b) calculated relative to the attenuation angle range. The structure of the secondary collimating optical device (33) includes a wall having at least a portion made of a material with a diffuse reflectance of at least 50%; and / or The structure of the secondary collimating optics (33) includes a wall having at least a portion of it made of a material with an absorption coefficient of at least 70% in the visible light range, which is positioned to intercept and absorb at least a portion of the diffuse light component (24b) emitted from the first emitting surface (25) at an angle greater than the attenuation angle (γ).

4. The lighting device (10, 10') according to any of the preceding claims, wherein the angular aperture (β) of the weak collimated light component (34b) measured with reference to the half-plane section (X) at the maximum half-width (HWHM) of the luminous intensity distribution is greater than 1.2 times the first angular aperture (α) of the first highly collimated light component (24a) measured with the maximum half-width (HWHM) of the luminous intensity distribution.

5. The illumination device (10, 10') according to any one of the preceding claims, wherein the dichroic separation optics (23) comprises a primary collimating optics (23a) configured to generate a highly collimated light component (24a) having a first angular aperture (α) intensity distribution starting from the primary light (22), and a diffuse light generator (23b, 23b', 23b'') configured to generate a diffuse light component (24b) having a second correlated color temperature (CCT2).

6. The lighting device (10, 10') according to claim 5, wherein the diffuse light generator (23b, 23b'') is a dispersive element configured to be transparent to at least a first spectral portion of light incident on the element and to scatter at least a second spectral portion of the incident light; and / or in, The diffuse light generator (23b, 23b'') is a tunable dispersive element configured to primarily change the scattering efficiency of the dispersive element in at least the second spectral portion of the incident light; and / or The diffuse light generator (23b, 23b'') is a tunable dispersive element comprising a substrate made of a polymer material in which liquid crystal (LC) nanodroplets are trapped; and / or Wherein, the diffuse light generator (23b, 23b'') is a dispersive element in the shape of a panel or a thin film, or the diffuse light generator (23b, 23b'') is a dispersive element configured as a surface coating or a surface anodized layer; and / or Among them, the diffuse light generator (23b') is an active diffuse light generator.

7. The illumination device (10, 10') according to claim 6, wherein the dispersive element (23b) is placed on the first emitting surface (25); or is placed on at least one interacting surface between the main light (22) and the main collimating optical element (23a).

8. The illumination device (10, 10') according to any one of the preceding claims, wherein the main collimating optical element (23a) of at least the dichroic separating optics (23) has axial symmetry, and the propagation direction is contained within the axis of symmetry of the main collimating optical element (23a); and The diffuse light generator (23b) has a circular or quadrilateral cross-section.

9. The lighting device (10, 10') according to any one of claims 1 to 7, wherein the main collimating optical element (23a) of the dichroic separating optical device (23) has an elongated shape along the extension axis of the device (10, 10') transverse to the propagation direction (A).

10. The lighting device (10, 10') according to claim 9, wherein the first optical unit (20) comprises a plurality of main light sources (21) arranged side by side and / or along an extension axis, wherein the dichroic separation optics (23) comprises at least one collimating lens associated with the plurality of main light sources (21) and is configured to collimate the light emitted by each main light source (21) about the respective propagation direction (A) of the plurality of parallel propagation directions (A).

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