Abstract: A lens for covering a light source to diverge light from the light source includes a light incident surface covering the light source, a light outputting surface positioned at lateral sides of the light incident surface; and a light reflecting surface positioned away from the light incident surface and interconnecting the light outputting surface. A reflectivity of the light reflecting surface is greater than a transmissivity thereof. Part of the light striking to the light reflecting surface is reflected by the light reflecting surface and traveling out of the lens via the light outputting surface. The other part of the light strikes to the light reflecting surface traveling out of the lens via the light reflecting surface. The light traveling through the lens has a viewing angle greater than 180 degrees.

Abstract: A luminous device comprises a light emitting diode (LED) light bar, a heat dissipating device thermally connected with the LED light bar, and a lamp cover made of light permissive material, engaging with the heat dissipating device and covering the LED light bar. The lamp cover is semicylindrical shaped and comprises an outer surface and an inner surface opposite to the outer surface and facing the LED light bar. A thickness of the lamp cover in a radial cross section thereof gradually reduces from a middle of the lamp cover to two opposite lateral sides thereof. Light generated by the LED light bar converges toward a plane orthogonally extending through the middle of the lamp cover after the light travels through the lamp cover.

Abstract: A lens includes a light incident surface and a light exiting surface. The light exiting surface includes a first concave surface, a first convex surface, a second convex surface, a first curved surface, and a second curved surface. The first concave surface is located at the center of the light exiting surface for diverging the light exiting therefrom. The first and second convex surface are arranged at two opposite sides of the first concave surface respectively for converging the light exiting therefrom; the first convex surface, the first concave surface, and the second convex surface connect in sequence along a first direction. The first and second curved surfaces are arranged at another two opposite sides of the first concave surface respectively; the first curved surface, the first concave surface, and the second curved surface connect in sequence along a second direction perpendicular to the first direction.

Abstract: A lens includes a light incident surface and a light exiting surface. The light exiting surface includes a first concave surface, a first convex surface, a second convex surface, a first curved surface, and a second curved surface. The first concave surface is located at the center of the light exiting surface for diverging the light exiting therefrom. The first and second convex surface are arranged at two opposite sides of the first concave surface respectively for converging the light exiting therefrom; the first convex surface, the first concave surface, and the second convex surface connect in sequence along a first direction. The first and second curved surfaces are arranged at another two opposite sides of the first concave surface respectively; the first curved surface, the first concave surface, and the second curved surface connect in sequence along a second direction perpendicular to the first direction.