The optical lens embodiment of the invention refracts and reflects light emitted from the
light emitting diode chips on a unique combination of curved surfaces to obtain the desired
coupling to a lateral
light guide. The
system of curved surfaces redirects rays from multiple LED chips laterally by multiple
refraction and / or reflection. The optical lens has an
optical axis, and comprises a bottom surface and a curved reflecting surface having a
concave side. The
concave side is oriented to face said bottom surface at an
oblique angle. The reflecting surface surrounds the
optical axis. The lens comprises a first curved refracting surface having a
concave side facing the concave side of the reflecting surface and a second refracting surface extending as a smooth curve from the bottom surface to the first refracting surface. Light entering the lens through the bottom surface and directly incident on the reflecting surface is reflected from the reflecting surface at its concave side to the first refracting surface and refracted by the first refracting surface to exit the lens in a lateral direction with respect to the
optical axis of the lens. A first portion of light entering the lens through the bottom surface and directly incident on the second refracting surface is refracted by the second refracting surface to exit the lens in a lateral direction with respect to the optical axis of the lens. A second portion of light entering the lens through the bottom surface and directly incident on the second refracting surface is refracted by the second refracting surface to the first refracting surface, refracted by the first refracting surface to the reflecting surface, reflected by the reflecting surface at its concave side to the first refracting surface and refracted by the first refracting surface to exit the lens in a lateral direction with respect to the optical axis of the lens.