Abstract: An electronic device has an electrically adjustable shutter. The shutter may be placed in a transparent state or a nontransparent state. The shutter may overlap a portion of a display, may overlap a liquid contact indictor or a structure with text in a device, or may overlap an optical component such as an optical proximity sensor, ambient light sensor, visible light-emitting diode or laser, infrared light-emitting diode or laser, visible light image sensor, or infrared light image sensor. Control circuitry in the electronic device may place the shutter in an opaque state to hide an overlapped component from view or may place the shutter in a transparent state to allow the overlapped component to transmit or receive light. The adjustable shutter may exhibit changes in its transmission spectrum in different modes of operation and may be used as a camera filter or neutral density filter.

Abstract: An apparatus is disclosed for generation of electricity using sunlight focused onto multi junction photovoltaic cells having high conversion efficiency. The apparatus includes a large paraboloidal mirror of back-silvered glass, turned to the sun throughout the day, so as to provide an intense focus. Multiple photovoltaic cells are provided at the focus. The optics are configured to distribute sunlight without significant loss into separate regions matched to the photovoltaic cell size. A secondary optical system takes strongly focused sunlight near the focus of a single paraboloidal mirror and distributes it equally between the cells, and regions of equally concentrated sunlight are matched to cell size and are substantially co-planar, so that the cells may be grouped on flat circuit cards.

Abstract: A Fresnel lens includes multiple different zones. At least one of the zones may be an asymmetric zone that is radially asymmetric. The asymmetric zone may redirect light received from a light source located within a focal length of the Fresnel lens to a portion of a field of view of an image sensor. In some embodiments, multiple asymmetric zones may be implemented within the same Fresnel lens, which may have different radial asymmetry.

Abstract: An apparatus is disclosed for generation of electricity using sunlight focused onto multi junction photovoltaic cells having high conversion efficiency. The apparatus includes a large paraboloidal mirror of back-silvered glass, turned to the sun throughout the day, so as to provide an intense focus. Multiple photovoltaic cells are provided at the focus. The optics are configured to distribute sunlight without significant loss into separate regions matched to the photovoltaic cell size. A secondary optical system takes strongly focused sunlight near the focus of a single paraboloidal mirror and distributes it equally between the cells, and regions of equally concentrated sunlight are matched to cell size and are substantially co-planar, so that the cells may be grouped on flat circuit cards.