Abstract: An object of the present invention is to provide a light-emitting device comprising: a substrate, a first light-emitting semiconductor stack having a first transverse width, the first light-emitting semiconductor stack comprising a first active layer emitting a first radiation of a first dominant wavelength during operation; a second light-emitting semiconductor stack having a second transverse width less than the first transverse width and comprising a second active layer emitting a second radiation of a second dominant wavelength shorter than the first dominant wavelength during operation; and a first conductive connecting structure between the first light-emitting semiconductor stack and the second light-emitting semiconductor stack, wherein the first conductive connecting structure is lattice-mismatched to the first active layer and to the second active layer, the first light-emitting semiconductor stack is between the substrate and the second light-emitting semiconductor stack.

Abstract: A magnetic paper-feeding roller assembly is adapted to feed a piece of paper in a machine that requires paper-feeding and that includes a casing. The magnetic paper-feeding roller assembly includes a first roller and a second roller, both of which are adapted to be pivotably mounted in the casing. The first roller is made of a magnetically attractive material. The second roller produces a magnetic force to magnetically attract the first roller toward the second roller so as to maintain a predetermined gap between the first roller and the second roller.