Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S19/00—Lighting devices or systems employing combinations of electric and non-electric light sources; Replacing or exchanging electric light sources with non-electric light sources or vice versa
  • F21S19/005—Combining sunlight and electric light sources for indoor illumination
• • E—FIXED CONSTRUCTIONS
  • E06—DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; LADDERS
  • E06B—FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES, FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS, BLINDS, GATES
  • E06B3/00—Window sashes, door leaves, or like elements for closing wall or like openings; Layout of fixed or moving closures, e.g. windows in wall or like openings; Features of rigidly-mounted outer frames relating to the mounting of wing frames
  • E06B3/66—Units comprising two or more parallel glass or like panes permanently secured together
  • E06B3/663—Elements for spacing panes
  • E06B3/66309—Section members positioned at the edges of the glazing unit
  • E06B3/66376—Section members positioned at the edges of the glazing unit comprising lighting means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V33/00—Structural combinations of lighting devices with other articles, not otherwise provided for
  • F21V33/006—General building constructions or finishing work for buildings, e.g. roofs, gutters, stairs or floors; Garden equipment; Sunshades or parasols
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/02—Diffusing elements; Afocal elements
  • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
  • G02B5/0236—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element
  • G02B5/0242—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element by means of dispersed particles
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/02—Diffusing elements; Afocal elements
  • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
  • G02B5/0278—Diffusing elements; Afocal elements characterized by the use used in transmission
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
  • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
  • G02B6/0031—Reflecting element, sheet or layer
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0033—Means for improving the coupling-out of light from the light guide
  • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
  • G02B6/004—Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles
  • G02B6/0041—Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles provided in the bulk of the light guide
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0081—Mechanical or electrical aspects of the light guide and light source in the lighting device peculiar to the adaptation to planar light guides, e.g. concerning packaging
  • G02B6/0095—Light guides as housings, housing portions, shelves, doors, tiles, windows, or the like
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2105/00—Planar light sources
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2115/00—Light-generating elements of semiconductor light sources
  • F21Y2115/10—Light-emitting diodes [LED]
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2115/00—Light-generating elements of semiconductor light sources
  • F21Y2115/10—Light-emitting diodes [LED]
  • F21Y2115/15—Organic light-emitting diodes [OLED]
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
  • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
  • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
  • G02B6/002—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
  • G02B6/0021—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces for housing at least a part of the light source, e.g. by forming holes or recesses

Definitions

• the present invention is inherent to a composite transparent lighting device.
• US patent application 8,237,352 shows a photo-luminescent sheet to be coupled with LEDs lights having a uniform phosphor content at high concentration, and does not address the problem of transparency of the sheet.
• Purpose of the present invention is to overcome the drawbacks still present in the known art by providing a composite transparent lighting device that is uniformly transparent during day-time and capable at the same time of becoming a uniform light source of excellent quality during night-time (i.e. when turned on).
• a composite transparent lighting device comprising a transparent element with discrete light sources optically coupled with the transparent element perimeter, a reflective frame defining the boundaries of the composite transparent lighting device. Said reflective frame covers at least 80% of the composite transparent lighting device perimeter.
• the transparent element is characterized in that: a. said transparent element comprises a transparent matrix with a uniform dispersion of dielectric particles,
• said transparent matrix has an optical light extinction coefficient equal to or less than 0.,009 cm "1 , evaluated at 500 nm, and
• volume concentration of said dielectric particles is comprised between:
• p is the average dielectric particle size expressed in ⁇
• m is the ratio between the refractive index of the dielectric particles and the refractive index of the transparent matrix evaluated at 500 nm.
• the composite transparent lighting device has the dielectric particle volume concentration comprised:
• Figure 1 is a schematic representation of a view from above of a composite transparent lighting device according to the present invention
• Figure 2 is a schematic representation of a view from above of an alternate embodiment of a transparent lighting device according to the present invention.
• Figure 3 is a schematic view of a cross section of another alternate embodiment of a composite transparent lighting device according to the present invention, •
• Figure 4-6 show experimental data collected on the extinction coefficient variation over the visible spectrum, with three different types of material powders and with varying sample concentration loading,
• Figure 7 shows the representation of a recording of a CCD camera for a transparent subassembly made according to the present invention
• Figure 8 shows the representation of a recording of a CCD camera for a transparent subassembly not made according to the present invention.
• the inventors have found a set of features necessary to have an improved appearance of a lighting device also in its inoperative state, when its transparency is exploited for example in building windows, internal wall separators, lamps, and at the same time capable of providing good quality lighting when active, i.e. when the discrete light sources on its perimeter are turned on.
• good quality lighting it is meant that light is pleasantly diffused, without visible glares or light sparkles.
• Such features are a uniform distribution of low concentration of dielectric particles coupled with the use of a reflecting frame to direct and redirect via multiple reflections the light out of the panel. Such features and their combination are not disclosed in the known art.
• any point of the transparent lighting element containing the dielectric particles the number of particles within a 10 "2 cm 3 volume (with the condition that all the volume is encompassed in such constituting element) is equal or differs by less than 10% with respect to the average value in the panel.
• a simple way to verify this condition is to verify that the difference between the concentration in the central part of the lighting element and a periphery volume is equal to or less than 10%.
• the above definition takes also into account that the lighting constituting element containing the scattering particles may present a discontinuity (absence of dielectric particles) close to the edges of the lighting device and/or in the immediate whereabouts of the discrete light sources.
• Such periphery areas when present, are up to 3 cm from the lighting device borders.
• the composite transparent lighting device comprises a transparent element, with transparent element material it is intended a material whose optical light extinction coefficient a is equal to or less than 0,009 cm "1 evaluated at 500 nm.
• - lin and lout are respectively the incident light intensity and light intensity after having passed through the transparent element
• Preferred transparent materials for use in the present invention are glass, polymeric materials such as poly-methyl methacrylate (PMMA), poly-carbonate (PC), poly-siloxane resins, acrylic, epoxy resins and poly-vinyl butyral (PVB). These materials may be used alone or in combination with a transparent substrate, i.e. a thin layer of a transparent element (for example a PMMA layer containing a dispersion of dielectric particles) could be deposited over a glass substrate. Preferred transparent substrate thicknesses are comprised between 0, 1 and 6 mm.
• the dielectric particles concentration for a composite transparent lighting device according to the present invention should be low, meaning that the particles give an increase in the optical light extinction value by an amount comprised between 0,003 cm " 1 and 0,03 cm "1
• dielectric particle volume concentration values (volume of the particles with respect to volume of the matrix) comprised between:
• p is the average dielectric particle size expressed in ⁇
• m is the ratio between the refractive index of the dielectric particles and the refractive index of the transparent matrix evaluated at 500 nm.
• volume concentration for the dielectric particles concentration comprised:
• the maximum concentration of each constituent should not exceed the Cmax given in the formula.
• the above Cmin and Cmax limits for each constituent should be proportionally adjusted according with the relative concentration of the specific constituent with respect to the total volume of dielectric particles. For example, if it is present 40% vol/vol of scattering particle A and 60% of scattering particle B, the maximum and minimum concentration with respect to the matrix are given by the above formula corrected by a multiplying factor of 0,4 for scatterer A and 0,6 for scatterer B.
• suitable materials for the dielectric particles are: metallic oxides, in this case preferred are oxides of Ti, Al, Zr, Hf, Ta, Y, Yb; silicates, in this case preferred are aluminosilicates, Si0 2 , glass beads; white and transparent ceramic beads; white and transparent plastic beads; barium sulfate.
• the thickness of the matrix containing the uniform dispersion of dielectric particles is preferably comprised between 0, 1 and 6 mm.
• Another class of materials suitable to be used as dielectric particles in the composite transparent lighting device according to the present invention are inorganic phosphors such as Ce:YAG; orthosilicates, aluminosilicates, nitrides, oxynitrides doped with Europium, etc.
• the transparent element further contains a dispersion of luminescent dyes in concentration comprised between 10 "6 and 10 "9 mol/L.
• suitable luminescent dyes are: organic molecules as bipyridine derivate, coumarin, dicarbocyanine derivate, lactone, oxazine 720, naphtalimide derivate, phthalocyanine, hematoporphyrin, pyrromethene, thioxanthene, sulfoRhodamine, Rhodamine 6G, perylene derivatives, derivate of (iso)violanthrone; inorganic Quantum Dots (CuInS, ZnSe, ZnS, InP, CuInZnS etc.) or nano-phosphors.
• the composite lighting element perimeter presents an average reflectivity equal to or higher than 80%, this takes into account both the fact that a 100% reflectivity is an ideal value (even though materials with a reflectivity higher than 90% may be easily identified by a person skilled in the art being them rather conventional), as well as the fact that some portions of the perimeter of the device may not be reflective, for examples the portions in correspondence to the discrete light sources.
• the reflective frame may be given by a variety of equivalent solutions such as metal guides, deposition of metallic layers or films, high reflectance paintings or coatings.
• Example of discrete light sources useful to be adopted in the present invention are conventional LEDs, preferred is the use of blue or white LEDs, laser diodes, organic light emitting transistors (OLETs) or organic light emitting diodes (OLEDs). Those are preferably disposed on at least two sides of the composite transparent lighting device, and their number is such that the provided power is comprised between 5 and 18 W per meter of length along the device perimeter. Preferably such discrete light sources provide a total light output comprised between 2000 and 5000 lumen per each square meter of composite transparent lighting device surface.
• Figure 1 shows a schematic view from above of a first embodiment of a composite transparent lighting device 10.
• a set of discrete light sources 13, 13', 13" is inserted in the transparent element that contains the uniform dispersion of dielectric particles 11.
• the four sides 12, 12', 12", 12" ' of the composite transparent lighting device 10 are made reflective, for example by depositing a thin metal layer.
• FIG. 2 shows a schematic view from above of a second embodiment of a composite transparent lighting device 20, comprising the transparent element 21 that contains the uniform dispersion of dielectric particles, said element having a perimeter 22, a reflective frame 24 with an external perimeter and an internal perimeter 25, partially overlapping with the transparent element 21 containing the dielectric particles and discrete light sources 23, 23', 23",....
• frame 24 has been shown as a single element, but it is more convenient that is obtained by joining together a subassembly, i.e. the final frame is obtained by coupling together sub-frames, for example four sub-frames, one for each side of the composite transparent lighting device, this will simplify both the assembly operation, as well as service operation in case one or more discrete devices needs to be replaced.
• this is not limited to any specific shape, square and rectangular shapes (as the one shown in figures 1-3) are preferred, but also circular and oval shapes may be used.
• the shapes herein mentioned are provided just as non-limiting examples, since any other shape may be successfully adopted.
• Figure 3 shows a schematic cross-section view of a third embodiment 30 of a composite transparent lighting device according to the present invention.
• the transparent element 31 containing the uniform dispersion of dielectric particles is sandwiched between two transparent substrate material 35 and 35'; similarly to the case of figure 1, discrete light sources 33 and 33' go within the transparent element 31, and the boundary of the composite transparent lighting device 30 is given by a reflective frame 34 running alongside the perimeter of the device.
• frame 34 may be made by the joining of more sub-frames and should provide a suitable thermal dissipation.
• the embodiment shown in figure 3 is particularly preferred in case of building windows, said kind of windows having two external transparent substrates 35 and 35' providing a thermal insulating action as well as a protective action from ambient agents for the dielectric particles that in some cases may react with moisture or oxygen.
• a preferred alternative solution according to the embodiment shown in figure 3 consists in a thin film deposited on the surface of only one of the glass substrates 35 or 35' assembled maintaining an empty space between said glass substrates filled with inert gasses or dry air. This is especially the case when the composite transparent lighting device is assembled in a hermetically sealed manner and also filled in its empty space with an inert gas.
• Different Ce:YAG in a silicone matrix dispersions are made. Roll mills are used to disperse commercially available powders of Ce: YAG with sizes comprised between 5 and 10 ⁇ . First the highest concentration sample is made (CI) and then by successive dilution the other samples C2, C3, SI are made.
• Average dimension for Ce:YAG and Si0 2 particles is 7,5 ⁇ , while Ti0 2 particles were peaked at 0,1 ⁇ , so these values have been used as reference values for the particle size.
• experiment 1 The various samples described in experiment 1 have been characterized in terms of the extinction coefficient over the visible wavelength spectrum by means of a UV- Vis JASCO spectrometer.
• FIG. 5 shows the results obtained for comparative sample C4 (semi-continuous line L5), comparative sample C5 (semi-continuous line L6), comparative sample C6 (semi-continuous line L7) and sample S2 (dotted line L8), while figure 6 shows the results obtained for comparative sample C7 (semi-continuous line L9), comparative sample C8 (semi-continuous line L10), comparative sample C9 (semi- continuous line Ll l), comparative sample CIO (semi-continuous line L12) and sample S3 (dotted line L13).
• a 15 cm x 15 cm x 3 cm sandwiched structure is made with two external glass layers and an intermediate composite layer.
• the composite layer is made mixing a liquid polyvinyl-butyral precursor with Si0 2 spheres with radius peaked at 310 nm.
• the concentration of Si0 2 in matrix is of 5- 10 "6 Vol/Vol.
• the ratio between the refractive index of the dielectric particles and the refractive index of the matrix, called m, is 0,99.
• the liquid dispersion is deposited on the glass with doctor blading technique and a 0,4 mm thick layer is obtained.
• the polymerization occurs in situ through UV-curing in N 2 environment. Consequently a few micrometer thick layer of liquid dispersion is deposited on the cured layer and the capping glass layer is placed. A second polymerization under same conditions is applied.
• the reflective frame and discrete light sources are not mounted, but instead the subassembly is irradiated from the right upper portion, with a collimated 450 nm laser with 75 mW power.
• the output of a recording CCD digital camera is shown in figure 7, while figure 8 shows the results obtained with a similar sub-assembly without the middle (active) layer. It is possible to observe that in figure 8 are visible only two spots in correspondence to the laser beam incoming and outcoming, due to scattering on the panel interfaces/borders, with no recording of further scattering from the panel inner area.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Dispersion Chemistry (AREA)
• Architecture (AREA)
• Chemical & Material Sciences (AREA)
• Optical Elements Other Than Lenses (AREA)
• Planar Illumination Modules (AREA)
• Glass Compositions (AREA)
• Display Devices Of Pinball Game Machines (AREA)
• Seal Device For Vehicle (AREA)

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Citations (7)

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• 2013
  • 2013-05-10 IT IT000774A patent/ITMI20130774A1/it unknown
• 2014
  • 2014-05-09 US US14/786,137 patent/US9803819B2/en active Active
  • 2014-05-09 CN CN201480025084.2A patent/CN105164358B/zh active Active
  • 2014-05-09 WO PCT/IB2014/061318 patent/WO2014181296A1/en not_active Ceased
  • 2014-05-09 EP EP14728335.2A patent/EP2994590B1/en active Active
  • 2014-05-09 JP JP2016512469A patent/JP6407259B2/ja active Active

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