Patent ID: 8371725

Claim:
A shaped optical prism structure, comprising an optical prism set horizontally in a perpendicular manner relative to a vertical line, said optical prism being arranged on a light-outgoing surface of a lamp, said lamp comprising a lampshade and at least one light source adapted for emitting light rays upwardly in a parallel manner out of said light-outgoing surface into said optical prism, a dimension and sloping angle of said optical prism being designed in a symmetric manner based on said vertical line, wherein said optical prism comprises: two recessed flat incident surfaces of a cross section of said optical prism sloping inwardly and symmetrically from a center area of a bottom side thereof toward said vertical line, a size of each said recessed flat incident surface, when projected onto a horizontal plane, being about one half of the size of said light-outgoing surface of said lamp, the combined size of said two recessed flat incident surfaces, when projected onto a horizontal plane, being equal to the size of said light-outgoing surface of said lamp, said recessed flat incident surfaces being defined to be the light incident surfaces of said optical prism; a light-outgoing surface connected to said recessed flat incident surfaces and adapted for output of light rays out of said optical prism; two recessed primary full-reflection surfaces of the cross section of said optical prism sloping inwards from a top side thereof toward said vertical line and adapted for primarily and fully reflecting the incident light falling upon said recessed flat incident surfaces; and a curved light-distribution surface formed of a series of sloping surfaces at the periphery of said optical prism for fully reflecting incident light secondarily, said sloping surfaces sloping at different angles, said curved light-distribution surface having a top side thereof connected with a top edge of said two recessed primary full-reflection surfaces and a bottom side thereof connected with said light-outgoing surface, said sloping surfaces of said curved light-distribution surface sloping from the top side of said curved light-distribution surface toward the bottom side of said curved light-distribution surface in an outward manner away from a center line of said optical prism; and wherein light rays emitted by said at least one light source enter said optical prism through said two recessed flat incident surfaces and then are primarily reflected by said two recessed primary full-reflection surfaces and secondarily reflected by said curved light-distribution surface and then refracted by the light-outgoing surface of said optical prism toward a predetermined area right below said lamp.