Artificial lighting system for simulating a natural lighting

Patent metadata

Field	Value
Publication number	US-2016281960-A1
Application number	US-201314442583-A
Country	US
Kind code	A1
Filing date	Nov 14, 2013
Priority date	Nov 14, 2012
Publication date	Sep 29, 2016
Grant date	—

Abstract

A lighting system for illuminating an environment with a lighting that simulates natural lighting, which includes: a first light source which emits a beam of visible light; a diffused-light generator delimited by an inner surface, which receives the light beam, and an outer surface, the diffused-light generator being at least partially transparent to the light beam. The diffused-light generator transmits at least part of the light beam and emits, through the outer surface, visible diffused light, the correlated color temperature of the transmitted light being lower than the CCT of the visible diffused light. The lighting system includes a dark structure which is optically coupled to the environment via the diffused-light generator and provides a substantially uniform background to the first light source.

First claim

1 . A lighting system for illuminating an environment with a lighting that simulates natural lighting, which comprises:
a first light source configured to emit a beam of visible light; a diffused-light generator delimited by an inner surface configured to receive the light beam, and by an outer surface, said diffused-light generator being at least partially transparent to the light beam, being configured to transmit at least part of the light beam, and being further configured to emit, through the outer surface, visible diffused light, the correlated color temperature (CCT) of the transmitted light being lower than the CCT of the visible diffused light; a dark structure, which is configured to be optically coupled to the environment via the diffused-light generator, and wherein:
at least one portion of the dark structure has a substantially uniform absorption coefficient in the visible range, and the dark structure is configured to provide a substantially uniform background to the first light source; and/or
at least one portion of the dark structure has an absorption coefficient in the visible range at least equal to 70%, and the dark structure is configured to provide a dark background to the first light source.

2 . The lighting system according to claim 1 , wherein said at least one portion of the dark structure has a substantially uniform absorption coefficient in the visible range, and the dark structure is configured to provide a substantially uniform background to the first light source; and wherein said at least one portion of the dark structure has an absorption coefficient in the visible range at least equal to 70%, and the dark structure is configured to provide a dark background to the first light source.

3 . The lighting system according to claim 1 , wherein the dark structure is configured to prevent the external light from illuminating the diffused-light generator from upstream.

4 . The lighting system according to claim 1 , wherein the dark structure is configured so that, when the first light source is on, and given a direction sheaf with a top angle of at least 0.1 sterad, in any first point of at least one portion of the outer surface, a first and a second background luminances of said first point differ from one another by no more of 50% of the first background luminance, said first and second background luminances being measured respectively in a first and a second observation directions, the first observation direction being parallel to any of the directions of the direction sheaf and non-parallel to any of the local dazzling directions, the second observation direction being set apart from the first observation direction by an angular distance in the range 0.3°-1° and being non-parallel to any of the local dazzling directions, said local dazzling directions being the directions which are set apart by less of 3° from any direction under which the first light source is seen from said first point, each of said first and second background luminances being formed only by the light rays which have hit the dark structure and have never passed through the environment.

5 . The lighting system according to claim 4 , wherein said direction sheaf is conical and has an axis directed along an axis direction, said axis direction being parallel to a direction under which the first light source is seen from at least a second point of said portion of the outer surface.

6 . The lighting system according to claim 4 , wherein the dark structure is further configured to prevent that, when the first light source is on, said first background luminance is greater than a threshold luminance value equal to 30% of the overall luminance of said first point in said first observation direction, in the absence of light rays coming from the environment.

7 . The lighting system according to claim 1 , wherein said portion of the dark structure has an area at least equal to 50% of the area of the inner surface.

8 . The lighting system according to claim 1 , wherein said portion of the dark structure is edge-free.

9 . The lighting system according to claim 1 , wherein the diffused-light generator is such that the CCT of the transmitted light is not greater than the CCT of the light beam.

10 . The lighting system according to claim 1 , wherein the diffused-light generator is such that the CCT of the visible diffused light is greater than the CCT of the light beam.

11 . The lighting system according to claim 1 , wherein the first light source is configured so that, on the inner surface, the illuminance varies between a minimum value and a maximum value, the maximum value being not greater than three times the minimum value.

12 . The lighting system according to claim 1 , wherein the diffused-light generator is arranged with respect to the first light source so that the relation
|tan(θ 1 −θ e )|≦0.5·cos(θ 1 )
holds true, wherein:
θ 1 is the angle at which a first light ray of the light beam, which originates from the barycenter of an emitting surface of the first light source, impinges on the barycenter of the inner surface; and
θ e is the angle at which a second light ray, which originates from the barycenter of the emitting surface of the first light source, impinges on a point of the boundary of the inner surface, said point being the point among the points of the boundary having maximum distance from the barycenter of the inner surface.

13 . The lighting system according to claim 1 , wherein the diffused-light generator is arranged with respect to the first light source so that the relation
|tan(θ 1 −θ 2 )|≦ X ·cos(θ 1 )/ L
holds true for at least one point of the inner surface spaced apart from a barycenter of the inner surface by X, wherein:
θ 1 is the angle at which a first light ray of the light beam, which originates from the barycenter of an emitting surface of the first light source, impinges on the barycenter of the inner surface;
θ 2 is the angle at which a second light ray, which originates from the barycenter of the emitting surface of the first light source, impinges on said at least one point of the inner surface; and
L is equal to, or greater than, three meters.

14 . The lighting system according to claim 1 , wherein the diffused-light generator is arranged with respect to the first light source so that the relation
|tan(θ 1 −θ 2 )|≦ X ·cos(θ 1 )/ L
holds true for at least one point of the inner surface spaced apart from a barycenter of the inner surface by X, wherein:
θ 1 is the angle at which a first light ray of the light beam, which originates from the barycenter of an emitting surface of the first light source, impinges on the barycenter of the inner surface;
θ 2 is the angle at which a second light ray, which originates from the barycenter of the emitting surface of the first light source, impinges on said at least one point of the inner surface; and
L is equal to at least 70% of the maximum distance between any two points of the inner surface.

15 . The lighting system according to claim 1 , wherein the first light source is arranged off-axis with respect to a line perpendicular to the inner surface and passing through the barycenter of the inner surface.

16 . The lighting system according to claim 1 , further comprising a reflective optical system arranged inside the dark structure and configured to convey the light beam onto the inner surface, said reflective optical system being such that light rays coming, in use, from the inner surface and impinging onto the reflective optical system are not reflected onto the inner surface.

Assignees

• Coelux Srl

Inventors

• Di Trapani Paolo
• Magatti Davide

Classifications

• E06B7/28

  Other arrangements on doors or windows, e.g. door-plates, windows adapted to carry plants, hooks for window cleaners {(edge protecting devices for door leaves E06B3/88; special glazing; emergency glazing; double glazing E06B3/66)} · CPC title

• F21V3/04

  characterised by materials, surface treatments or coatings · CPC title

• F21V3/0615

  the material diffusing light, e.g. translucent glass · CPC title

• F21V3/0625

  the material diffusing light, e.g. translucent plastics · CPC title

• F21W2121/008

  for simulation of a starry sky or firmament · CPC title