Abstract: An optical system includes a plurality of separate light sources with a number M of the light sources arranged in a first direction and a number N of the light sources arranged in a second direction. Each of the light sources has an asymmetric light emission area. The light sources are arranged so that a light beam passing a collimator optical element has a beam width in the first direction greater than a beam width in the second direction. An anamorphic optical element is arranged to have a beam-size reduction rate in the first direction greater than a beam-size reduction rate in the second direction and converts the plurality of light beams from the light sources into a light beam having a symmetric beam cross-section. A light-condensing optical element condenses the light beam having the symmetric beam cross-section into a light receiving element, and the anamorphic optical element includes an array of a number of prisms integrally arranged.

Abstract: An optical system is disclosed that is compact and is capable of efficiently condensing light into a light receiving optical element. The optical system includes plural light sources and a light condensing portion. The light sources are arranged as an array with M light sources in the horizontal direction and N light sources in the vertical direction (M>N, and M, N>1). The light condensing portion includes a collimator optical element, an anamorphic optical element, and a light-condensing optical element. The anamorphic optical element is arranged such that its magnification in the horizontal direction is greater than that in the vertical direction. Due to the anamorphic optical element, the beam size in the horizontal direction is approximately equal to that in the vertical direction.