Microwave energized plasma lamp with solid dielectric waveguide
A plasma lamp including a waveguide body including at least one dielectric material with a dielectric constant greater than approximately 2. The body is coupled to a microwave source which causes the body to resonate in at least one resonant mode. At least one lamp chamber integrated with the body contains a bulb with a fill forming a light-emitting plasma when the chamber receives power from the resonating body. A bulb either is self-enclosed or an envelope sealed by a window or lens covering the chamber aperture. Embodiments disclosed include lamps having a drive probe and a feedback probe, and lamps having a drive probe, feedback probe and start probe, which minimize power reflected from the body back to the source both before each plasma is formed and after it reaches steady state.
1. An electrodeless plasma lamp comprising:
a lamp body comprising a dielectric material having a dielectric constant greater than 2;
an electrically conductive material forming an outer surface around the lamp body;
a power source configured to provide power to the lamp body at about a resonant frequency for the lamp body;
an electrodeless bulb containing a fill, the fill positioned within the lamp body to receive at least a portion of the power from the lamp body, the fill adapted to emit light when the power is received from the lamp body;
the electrically conductive material including an opening in the outer surface;
the bulb including at least a portion of light transmissive material recessed from the opening such that a light path is formed between the light transmissive material and the opening in the outer surface; and
the light transmissive material positioned between the fill and the opening in the outer surface such that the light emitted from the fill is transmitted through the light transmissive material and out of the opening.
2. The lamp of claim 1 , further comprising a reflector configured to direct the light out of the lamp body.
3. The lamp of claim 2 , wherein the reflector is formed on a surface of the solid dielectric material.
4. The lamp of claim 2 , wherein the reflector is spaced apart from the light transmissive material.
5. The lamp of claim 1 , wherein the light path is disposed within an opening formed by the dielectric material.
6. The lamp of claim 1 , wherein the light path comprises a light tunnel between the light transmissive material and the opening.
7. The lamp of claim 1 further comprising a hollow reflective optical element to direct light away from the lamp body.
8. The lamp of claim 7 wherein the optical element is a tube lined with a reflective material.
9. The lamp of claim 1 further comprising a light pipe to direct light away from the lamp body.