Decorative lighting apparatus with light source and luminescent material

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
1 illustrates a lighting apparatus according to one embodiment of the invention.
The lighting apparatus 100 includes a light source 110 powered via electrical connectors 112, an optical coupler 120, a transmissive body 130, and at least one region of luminescent material 140.
The light source 110 typically comprises a light emitting diode (LED) or a laser diode.
For example, the light source may comprise an LED or a laser diode which emits ultraviolet (UV) or blue light.
Such LEDs and laser diodes are available commercially from Nichia Industrial Chemicals Ltd.
in Japan.
Examples of LEDs which emit blue or UV radiation are described in U.
S.
Pat.
Nos.
5,813,752 and 5,813,753.
Examples of laser diodes which emit blue or UV radiation are described in U.
S.
Pat.
Nos.
5,604,763 and 5,644,584.
See also Shuji Nakamura and Gerhard Fasol, "The Blue Laser Diode" (1997).
The light source 110 can be optically coupled to the transmissive body 130 by an optical coupler 120.
The optical coupler 120 may be in the shape of a truncated cone such that substantially all the radiation emitted from the light source 110 is coupled into the transmissive body 130.
The optical coupler 120 and the transmissive body are preferably transparent in the wavelengths emitted by the light source 110.
Typically, the optical coupler 120 and the transmissive body 130 are formed of a flexible material such as a polymer (e.
g.
epoxy or thermoplastic), a silicone, or a glass.
For example, a polymer material having a thickness on the order of 1 mm may be flexible enough to bend with a radius of curvature of 1 mm or less without damage to the material.
The optical coupler and transmissive body can be formed integrally as a single piece, in which case the optical coupler is merely the end portion of the transmissive body.
The lighting apparatus 100 is typically configured such that substantially all the light from the light source 110 is transmitted through the transmissive body 130 by total internal reflection