A generally plano rectangular louvers are capable of being ganged in a stacked tiltable array to enhance light re-direction when titled to follow the solar elevation. Combinations of features and optical characteristic avoid optical artifacts and enhance efficiency of light utilization and manufacturing. Different louvers can be combined in alternative ways in such arrays. Light directly louvers, films, sheets and panels deploy a grooves that re-direct exterior sunlight for deeper penetration into rooms and building interiors. Absorbing structure are combined with films or panel that while reducing total interior illumination, reduce the potential for annoying glare at low solar elevations

There is provided a light collecting device comprising a concave portion for receiving incoming light. The concave portion comprises a reflective inner surface for directing at least partly the incoming light toward a focal spot, which is defined by a geometry of the concave portion. A light guide holder is held in place at the focal spot and holds a light-receiving end of a light guide, inside its annular shape. It holds the light-receiving end toward the concave portion to substantially capture the incoming light directed toward the focal spot. The concave portion can be a dish or a lamp reflector. The light guide holder can be held in place by arms having pads that rest on or hold the concave portion.

A light-diffusion member includes a plurality of cylindrical lenses arrayed in a prescribed direction, wherein the cylindrical lenses are arrayed in a first direction and extended in a second direction that is perpendicular to the first direction, the cylindrical lenses each have a curved lens surface, and the lens surface has a height that continuously changes with a prescribed period in a cross-section of the cylindrical lens taken along a second imaginary plane that is perpendicular to a first imaginary plane containing both the first direction and the second direction and that is parallel to the second direction.

A novel lighting system includes a solar collector panel comprising a plurality of reflector elements configured to track and be oriented optimally to receive electromagnetic radiation from the sun and reflect the received electromagnetic radiation toward a skylight in a roof of a building, a dichroic mirror disposed in the skylight and oriented and configured to receive the reflected electromagnetic radiation from the solar collector panel, the dichroic mirror being configured to reflect electromagnetic radiation of a first specific range of wavelengths downward into the building and pass through electromagnetic radiation of a second specific range of wavelengths, and a photovoltaic panel oriented and configured to receive electromagnetic radiation of the second specific range of wavelengths that passed through the dichroic mirror and convert it to electricity.

There is provided a unit for light conversion in a building. The unit comprises a solar panel comprising photovoltaic cells without any light-absorbing or light-reflecting coating such as to be raw. The photovoltaic cells can have a wavelength range of conversion optimized for natural sunlight. The unit further comprises an enclosure surrounding the solar panel and preventing the exposure of the solar panel from direct light from outside the enclosure, the enclosure comprising an input. There is provided a light guide comprising an optical fiber and adapted for optical connection to the light collector, the light guide being connectable to the enclosure via the input, the light guide having an output end located by the input of the enclosure and directed toward a surface of the photovoltaic cells for illumination thereof. A light collector is provided outside the building for collecting sunlight and guiding the sunlight into the light guide.

A light box is designed to receive sunlight guided through optical-fibers and to divert it through optics onto a photovoltaic chip which converts sunlight into electrical energy. The optics can be arranged as a prism or a reflective surface. The chip is not integrated with the light box.

A sunlight-based projector system (3) is disclosed for providing a direct light beam (5). The projector system (3) comprises a sunlight receiving unit (9) with a collector system (13), a plurality of optical fibers (15), and a plurality of fiber output channels (44). The collector system (13) collects natural outdoor light, and couples the collected light into the plurality of optical fibers (15). The projector system (3) comprises further a sunlight forming unit (11) with a plurality of optical collimator units (47) arranged in a two-dimensional array, wherein each optical collimator unit (47) receives the respective fiber output light (45) and comprises at least one optical collimator (49) for reducing the angular distribution width of the received divergent fiber output light (45). Output areas of the plurality of optical collimator units (47) form essentially a continuously extending large light-emitting face (53) of the sunlight forming unit (11) for emitting an essentially collimated light beam (5). The generated direct light beam (5) may be used together with diffused light generating areal units to provide a sun-sky imitating lighting system with a sun-like appearance.

A light source (25) for emitting collimated light (29) in particular for a large area luminaire (21) comprises a light guide unit (43) for guiding light by total internal reflection. The light guide unit comprises a plurality of localized light source regions (57) at a main front face (55A) for having light pass there through. The light source (25) further comprises a plurality of light emitting units (41) for emitting light into the light guide strips (91) through respective portions of the at least one coupling face (47) of the light guide unit (43), and a collimation unit (45) extending along the main front face (55A) and comprising a plurality of collimating elements. At least one light emitting unit (41) is configured as a light input coupling assembly (250) to receive collected natural light from a fiber (249) and to provide the received natural light to the light guide unit (43). The light source (25) can be implemented in a sunlight-based illumination system (241) collecting and providing natural light to the light source (25).

A daylighting apparatus of the present invention includes: a daylighting sheet (13) that has first and second surfaces opposite to each other and that lets light in through the first surface and lets the light out through the second surface at a predetermined distribution of angles; and a visible light-reflecting sheet (15) that reflects part of visible light falling on the first surface of the daylighting sheet (13).

A method for increasing availability of light at a target area, comprising: selecting, at a time of manufacture of a convex reflective surface or optical equivalent thereof, maximum and minimum inclinations and curvature determined by an orientation and latitude and range of azimuths available for insolation at a location where the convex reflective surface or optical equivalent thereof is to be mounted, such that the convex reflective surface or optical equivalent thereof will, when mounted, deflect insolation to the target area without adjustment of a position, inclinations, or curvature of the convex reflective surface; statically mounting the convex reflective surface in a fixed orientation at the position above the target area, and deflecting sunlight received at the convex reflective surface vertically or obliquely downwards onto the target area without adjustment of the position, inclinations, or curvature of the convex reflective surface or optical equivalent thereof throughout the day.