A light emitting diode chip or chips array mounted on a substrate is
surrounded by one or more side walls. The wall has an uneven reflecting
surface to diverge the light emitted from the LED chip or chip array. The
wall may have a triangular cross-section so that the emitted light
diverges in all directions. When three double-sided reflecting walls
surround three LED panels, the reflected light becomes omnidirectional
hemispherically and can be used in a light bulb.