NOVELTY - The device (100) has a mirror (130) arranged on convex lower surface (115), where the mirror and convex lower surface are arranged such that sunlight passing through a flat upper aperture surface (112) is reflected and focused by the mirror to a linear region of the upper aperture surface. A linear solar-energy collection element e.g. string of photovoltaic cell, fixedly arranged to receive the focused light reflected by the mirror. A tracking system (140) rotates the trough reflector around an axis that is non-parallel to the upper aperture surface.    USE - Trough reflector-type solar-electricity generation device for use in a rooftop of a house and in a business area.    ADVANTAGE - The trough reflector utilizes moderate solar concentration, thus reducing the amount of photovoltaic (PV) material required by the device. The reflector is rotated around an axis that is perpendicular to the focal line, and the reflector remains in-plane with or in a fixed, canted position relative to an underlying support surface, thus reducing engineering demand on the strength of the support structure and the amount of power required to operate the tracking system, and providing economical benefits. The device utilizes an optical element, thus reducing deleterious end effect by causing the refracted light to transit the optical element normal to the array, and reducing the amount of poorly or non-illuminated regions at the ends of the energy collection element. The optical element is solid, and the mirror and collection element remain permanently aligned, thus maintaining optimal optical operation while minimizing maintenance cost. The device reduces normal operating cell temperature (NOCT) of photovoltaic-based solar energy collection element. The optical element is positioned between the aperture surface and convex surface/mirror, and the convex surface/mirror and the solar energy collection element, thus reducing loss of light at gas/solid interfaces. The active surface of the collection element and the mirror surface are permanently protected from dirt and corrosion by solid optical element material while leaving only the relatively easy to clean flat upper aperture surface exposed to dirt and weather. The device reduces profile, height, and cost of manufacture of the array. The mirror is essentially self-forming and self-aligned when the mirror is formed as a mirror material film, thus greatly simplifying manufacturing process and minimizing production cost.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for generating solar-electricity using a trough reflector.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded perspective view of a solar-electricity generation device.    Trough reflector-type solar-electricity generation device (100)    Flat upper aperture surface (112)    Convex lower surface (115)    Mirror (130)    Tracking system (140)