Method of making illumination systems employing reflective grids

A method of making illumination systems for illuminating building interiors, comprising:

• providing a first reflective side wall formed from an opaque rigid material;
• providing a second reflective side wall formed from the opaque rigid material;
• positioning the first and second reflective side walls at a distance from one another such that a reflective surface of the first reflective side wall is facing a reflective surface of the second reflective side wall;
• providing a reflective grid panel comprising a plurality of parallel longitudinal walls and a plurality of parallel transverse walls joining the plurality of parallel longitudinal walls and defining a plurality of rectangular openings configured to transmit light;
• positioning the reflective grid panel in a space between the first and second reflective side walls;
• providing an LED light source;
• positioning the LED light source above the reflective grid panel so as to illuminate the reflective grid panel at incidence angles ranging from a minimum angle of 0° to a maximum angle of at least 45°;
• providing a light diffusing sheet of an optically transmissive dielectric material which is approximately coextensive with the reflective grid panel;
• positioning the light diffusing sheet of the optically transmissive dielectric material in the space between the first and second reflective side walls in a parallel orientation with respect to the reflective grid panel and above the reflective grid panel;
• and
• wherein each of the first and second reflective side walls extends transversely with respect to a plane of the reflective grid panel and is configured to diffusely reflect a portion of light being transmitted through the plurality of rectangular openings.