Sunlight-based large area light source and large area luminaire

The light source (25) of any one of the preceding claims, wherein the plurality of light source regions (57) is distributed over the non-source region (59) at equal distances with respect from each other.

The light source (25) of any one of the preceding claims, wherein the ratio of the area of the plurality of light source regions (57) with respect to the area of the main front face (55A) and/or the area of the non-source region (59) is less or equal to 16% such as 15% or less or less or equal to 10% such as less or equal to a few percent such as less or equal to 5% such as less or equal to 2% such as less or equal to 0.2%.

The light source (25) of any one of the preceding claims, wherein the light guide unit (43) comprises two opposite lateral light coupling faces (47) each being associated with a subgroup (51A, 51B) of light emitting units (41) of the plurality of light emitting units (41) for coupling counter-propagating light into the light guide unit (43).

The light source (25) of any one of the preceding claims, wherein a light emitting face (63) is formed by the collimated light emitting regions (61), and the continuous light emitting face (63) comprises in particular non-emitting regions (65) between collimated light emitting regions (61) and the area ratio between the non-emitting regions (65) and the collimated light emitting regions (61) is essentially constant over the light emitting face (63) of the light source (25).

The light source (25) of any one of the preceding claims, wherein the distance between neighboring light source regions (57) is in the range from 0.5 mm to 50 mm such as about 3 mm or 6 mm (pitch distance in a light propagation direction), and/or wherein the light source (25), and in particular the light guide unit (43), is configured such that the flux of light emitted from the light source regions (57) is at least 10 times or at least 20 times or even more than 50 times as much as any leakage flux of light through the non-source regions (59), and/or

• wherein the light source regions (57) are distributed within and in particular substantially surrounded by the non-source region (59).

The light source (25) of any one of the preceding claims, wherein the extension of the light guide unit (43) in directions defined by the shape of the main front face (55A) is much larger than the thickness of the light guide unit (43) in the thickness direction (dT), and the light guide unit (43) is in particular panel shaped having a thickness in the range from 1 mm to 5 mm and a lateral extension such as a diameter, a width, and/or a length in the range from 0.05 m to 3 m such as in the range from 0.1 m to 2 m, and/or wherein the main front face (55A) and the main back face (55B) are opposite and essentially parallel to each other.

The light source (25) of any one of the preceding claims, wherein the light guide unit (43) comprises a plurality of optically separated light guide strips (91), each light guide strip (91) comprising at least one lateral coupling face section optically coupled to at least one of the plurality of light emitting units (41), and a subgroup of the plurality of light source regions (57), the subgroup in particular being arranged linearly along the light guide strip (91) at equal distances, wherein that pitch (p) between neighboring light source regions (57) along the strip (91) is, for example, in the range from 1 mm to 50 mm such as about 3 mm, and/or

• wherein the light guide strip (7) has a rectangular cross-section with a thickness in the range from 0.1 mm to 5 mm, a lateral width in the range from 0.1 mm to 5 mm, such as a cross-section of 300 μm×300 μm, and a length in the range from 0.1 m to 2 m, and/or
• wherein plurality of light guide strips (91) is mounted to a substrate (191), in particular at the respective sides of the light guide strips (91) that are associated with the main back face (55B) of the light guide unit (43).

The light source (25) of any one of the preceding claims, further comprising

• a cross-talk reducing baffle structure (157) extending between and/or along collimating elements, thereby reducing the amount of light from a light source region (177) entering a collimating element associated with a neighboring collimating element, and/or
• a front leakage blocking structure (159) extending between collimating elements along the main front face (55A), and/or
• a back leakage blocking structure (105) extending along the main back face (55B) and in particular configured as a heat sink.

The light source (25) of any one of the preceding claims, wherein at least one of the plurality of light emitting units (41) comprises a light emitting device such as an encapsulated or a non-encapsulated light emitting devices (LEDs, 81E), a laser diode (83A) such as a butt-coupled laser diode (83A), and/or a refractive or a reflective coupling optic such as a lens or compound parabolic concentrator lens, and wherein in particular at least some of the plurality of light guide strips (91) are optically connected to a light emitting unit (93B), e.g. via a beam splitter configuration (95) in particular using fiber optical waveguides.

The light source (25) of any one of the preceding claims, wherein at least one of the plurality of light emitting units (41) comprises a light emitting device with a light emission over an angular range that results in an angular range (207) within the light guide unit (34) of below 40° such as below or about 30° or 20°, e.g. about 10°, and/or

• wherein the angular range (207) is characterized by an input light central direction (209) and the input light central direction (209) is inclined with respect to the normal to the main front face (55A) or main back face (55B) of light guide unit (43), and/or
• wherein at least one of the plurality of light emitting units (41) comprises a white light emission spectrum, and/or wherein the plurality of light emitting units (41) comprises a variation of emission spectra.

The light source (25) of any one of the preceding claims, further comprising a plurality of down-conversion elements such as a phosphor compound or a quantum dot region, wherein each down-conversion element is associated with a light source region (57) and in particular

• a down-conversion element of the plurality of down-conversion elements is positioned to receive light having passed through the light source region (57), and/or
• a down-conversion element of the plurality of down-conversion elements is positioned next to the main front face (55A) or the main back face (55B) to generate light from light having passed through the light source region (57) or to generate light to pass through the light source region (57), and/or
• a down-conversion element of the plurality of down-conversion elements is positioned at the input side of a respective collimating element of the collimation unit (45).

The light source (25) of any one of the preceding claims, further comprising a plurality of reflective structures (117) respectively associated with a light source region (177) and wherein in particular

• a reflective structure (117) of the plurality of reflective structures (117) is positioned and configured to reflect light to pass through the light source region (177), and/or
• a reflective structure (117) of the plurality of reflective structures (117) is positioned and configured to reflect light onto a respective down conversion element, and/or
• a reflective structure (117) of the plurality of reflective structures (117) is configured as focusing reflector.

The light source (25) of any one of the preceding claims, further comprising a plurality of reflective structures (117) respectively associated with a light source region (177) and wherein in particular

• a reflective structure (117) of the plurality of reflective structures (117) is positioned and configured to reflect light falling onto it from opposite directions to pass through the light source region (177) in a similar extraction direction, and/or
• a reflective structure (117) of the plurality of reflective structures (117) is configured as a reflective prism formed on the main back side, the reflective prisms (221) extending in the thickness direction over, for example, 100 μm, for example by having a lateral size of about 100 μm and slope angle of about 45°, and/or
• a reflective structure (117) of the plurality of reflective structures (117) has a triangular cross section when looked at from the side and a round cross section when looked at from the respective collimating element, e.g. by having a reflecting side (227A, 227B) that is shaped half-ellipse like such as half-circle like.

The light source (25) of any one of the preceding claims, wherein at least one of the plurality of collimating elements comprises a refractive optic and/or a reflective optic such as one or more lenses, in particular a TIR lens or a TIR lens followed by a lens such as a Fresnel lens, and/or a compound parabolic concentrator, in particular a compound parabolic concentrator followed by a lens such as a Fresnel lens, and/or

• wherein at least one of the plurality of collimating elements comprises a circular or polygon base shape aperture (35) for the collimated light emitting region (61) such as a triangular, quadratic, or hexagonal shape, and/or wherein the collimating unit comprises a base structure for holding the collimating elements at respective positions and the base structure is in particular configured as the baffle structure.

The light source (25) of any one of the preceding claims, further comprising a light emitting face (63) formed by the collimated light emitting regions (61), and/or wherein the input side of a collimating element is optically associated to one of the plurality of light source regions (57) and/or

• wherein at least one of the plurality of collimating elements further comprises a lens such as a Fresnel lens, which is associated with a respective compound parabolic concentrator or TIR lens and collimates light exiting the compound parabolic concentrator or TIR lens, thereby forming the collimated light beam (29), and/or
• wherein the collimated light emitting regions (61) are defined by the lens, and/or
• wherein the collimated light emitting regions (61) are defined by exit faces of the compound parabolic concentrator or TIR lens.

The light source (25) of any one of the preceding claims, wherein at least one of the plurality of collimating elements is configured to provide at least one main light beam propagation axis for the propagation of the collimated light (29) that is orthogonal or inclined with respect to the light emitting face (63), and wherein in particular all collimating elements are configured to provide for the same main direction and/or wherein in particular an inclination of the direct light as generated by a displacement of the optical axes of components of the collimating elements with respect to each other or with respect to the light source region, such as a displacement of a compound parabolic concentrator or a TIR lens and a Fresnel lens.

The light source (25) of any one of the preceding claims, further comprising

• at least one driving unit for driving the plurality of light emitting units (61),
• at least one power supply (173), and
• a control unit (34) for controlling the at least one driving unit for example including a clock control, and wherein in particular a subgroup of the plurality of light emitting units (61) is controllable by a respective driving unit, thereby allowing an intensity control and/or color tuning control of the collimated light (29).

An edge-lit large area luminaire (21) comprising

• a light source (25) as in any one of the preceding claims, and
• a chromatic diffusing layer (27) comprising a plurality of nanoscale scattering elements such as nanoparticles, nanodroplets, or nanovoids embedded in a matrix and configured to provide for a direct transmission that is larger in the red than in the blue and for a diffuse transmission that is larger in the blue than in the red, in particular positioned to be illuminated by the collimated light or to be positioned downstream of the light source regions (57) such as downstream of the input side and/or the output side of the collimation unit.