Abstract: An apparatus for generating electricity from solar energy has a large dish reflector with a fly's eye receiver positioned near the focus of the dish reflector, held by a dual axis tracking structure. The fly's eye receiver includes a field lens that concentrates sunlight into an image of the dish reflector, a two-dimensional fly's eye array of contiguous convex lenses extending across the dish image, and a photovoltaic cell behind each convex lens of the fly's eye array. Two imaging stages are provided. First, the dish reflector and the field lens concentrate the sunlight in the form of an image of the dish that is stabilized against pointing errors of the tracking mechanism. Second, the contiguous array of convex lenses divides the sunlight energy of the dish image into portions, one per convex lens, each portion being further concentrated by the respective convex lens onto a corresponding photovoltaic cell.

Abstract: A solar PV module is disclosed having two types of laterally-separated coplanar cells with different bandgaps to improve conversion efficiency. A diffracting entrance window directs sunlight with wavelengths shorter than a separation 5 wavelength ks is directed largely to the first type of wider bandgap cells. Sunlight with wavelengths longer than a separation wavelength ks is directed largely to the second type of narrower bandgap cells. The separation wavelength is chosen so that each cell is illuminated largely by that part of the solar spectrum to which it has the higher conversion efficiency, resulting in an overall conversion efficiency higher than 10 for either type of cell used alone. The wider bandgap cells are configured on a planar support in separated parallel strips, with the narrower bandgap cells largely filling the area between these strips.

Abstract: An apparatus for generating electricity from solar energy has a large dish reflector with a fly's eye receiver positioned near the focus of the dish reflector, held by a dual axis tracking structure. The fly's eye receiver includes a field lens that concentrates sunlight into an image of the dish reflector, a two-dimensional fly's eye array of contiguous convex lenses extending across the dish image, and a photovoltaic cell behind each convex lens of the fly's eye array. Two imaging stages are provided. First, the dish reflector and the field lens concentrate the sunlight in the form of an image of the dish that is stabilized against pointing errors of the tracking mechanism. Second, the contiguous array of convex lenses divides the sunlight energy of the dish image into portions, one per convex lens, each portion being further concentrated by the respective convex lens onto a corresponding photovoltaic cell.

Abstract: A solar concentrator may have a horizontal circular track on the ground, a tower centered on a vertical axis of the track, and a rotatable structure around the track having an upper, concave mounting surface approximating the shape of part of a sphere centered on the top of the tower. Articulated concave mirrors are attached to the rotatable structure, and the mirrors have a focal length approximately equal to the radius of a sphere portion formed by the concave mounting surface. Sunlight is focused at a receiver mounted atop the tower, and the receiver may convert sunlight into thermal or electrical energy. As the position of the Sun changes, sunlight is maintained on the receiver by turning the rotatable structure toward the Sun, turning the receiver about said vertical axis to face the mirrors, and articulating the mirrors toward the receiver in response to the changing elevation of the Sun.

Abstract: A solar PV module is disclosed having two types of laterally-separated coplanar cells with different bandgaps to improve conversion efficiency. A diffracting entrance window directs sunlight with wavelengths shorter than a separation 5 wavelength ks is directed largely to the first type of wider bandgap cells. Sunlight with wavelengths longer than a separation wavelength ks is directed largely to the second type of narrower bandgap cells. The separation wavelength is chosen so that each cell is illuminated largely by that part of the solar spectrum to which it has the higher conversion efficiency, resulting in an overall conversion efficiency higher than 10 for either type of cell used alone. The wider bandgap cells are configured on a planar support in separated parallel strips, with the narrower bandgap cells largely filling the area between these strips.

Abstract: A solar concentrator may have a horizontal circular track on the ground, a tower centered on a vertical axis of the track, and a rotatable structure around the track having an upper, concave mounting surface approximating the shape of part of a sphere centered on the top of the tower. Articulated concave mirrors are attached to the rotatable structure, and the mirrors have a focal length approximately equal to the radius of a sphere portion formed by the concave mounting surface. Sunlight is focused at a receiver mounted atop the tower, and the receiver may convert sunlight into thermal or electrical energy. As the position of the Sun changes, sunlight is maintained on the receiver by turning the rotatable structure toward the Sun, turning the receiver about said vertical axis to face the mirrors, and articulating the mirrors toward the receiver in response to the changing elevation of the Sun.

Abstract: We disclose here a new type of solar generator using an optical concentrator in which sunlight is concentrated successively in each of two dimensions. Sunlight is first reflected toward a linear focus by a large, deeply-curved, cylindrical trough reflector of parabolic shape. Before the reflected light comes to the focus, it passes through smaller, regularly spaced toroidal arc lenses which further concentrate it in the orthogonal direction. The lenses have the two-dimensional cross section of a convex lens, extended into a toroid by rotation about an axis parallel to the line focus. The toroidal arc lenses operate to efficiently focus at very high-concentration converging rays that are incident from a wide range of directions, from the deeply curved primary reflector. The foci formed by the toroidal arc lenses are formed at regular intervals, spaced along a line parallel to and close to the primary linear trough focus.