Plasma lamp with dielectric waveguide
A dielectric waveguide integrated plasma lamp is disclosed for powering a small and bright bulb with a diameter of a few millimeters. The lamp is contained within a high dielectric constant material which guides the microwaves to the bulb, provides heat isolation to the drive circuit, contains the microwaves, provides structural stability and ease of manufacturing and allows efficient energy coupling to the bulb when used as a dielectric resonant oscillator.
1. A plasma lamp comprising:
a waveguide body having a dielectric constant greater than about 2;
an RF source including an input and an output, the output coupled to the waveguide body at a first location to provide RF energy to the waveguide body;
the input of the RF source coupled to the waveguide body at a second location to obtain feedback from the waveguide body; and
a bulb adjacent to the waveguide body, the bulb containing a gas that forms a plasma when the RF energy is applied to the waveguide body through the first feed.
2. The plasma lamp of claim 1 , wherein the RF source uses the feedback to adjust the frequency of the RF energy applied to the waveguide body to maintain at least one resonant mode.
3. The plasma lamp guide of claim 1 , wherein a cavity is formed in the dielectric waveguide body and the bulb comprises the cavity and a window.
4. The plasma lamp of claim 1 , wherein a cavity is formed in the dielectric waveguide and the bulb is positioned in the cavity.
5. The plasma lamp of claim 1 , wherein the RF source is configured to use the feedback to provide an immediate re-strike capability when the plasma is extinguished.
6. The plasma lamp of claim 1 further comprising an amplifier coupled to the RF source and the waveguide body to provide the feedback.
7. The plasma of claim 2 wherein, the first location is at a resonant field maximum.
8. The plasma of claim 2 , wherein the bulb is positioned at a resonant field maximum.
9. A plasma lamp comprising:
a waveguide body having a dielectric constant greater than about 2;
a first feed coupled to the waveguide body to provide RF energy to the waveguide body;
a second feed coupled to the waveguide body to obtain feedback from the waveguide body; and
a bulb adjacent to the waveguide body, the bulb containing a gas that forms a plasma when the RF energy is applied to the waveguide body through the first feed.
10. The plasma lamp guide of claim 9 , wherein the first feed is embedded within the waveguide body.
11. The plasma lamp of claim 9 , wherein the second feed is embedded within the waveguide body.
12. The plasma lamp of claim 9 , further comprising an amplifier coupled to the second feed.
13. The plasma lamp of claim 9 , wherein the waveguide body is configured to resonate when the RF energy is applied to the waveguide body.
14. The plasma lamp of claim 13 , wherein the first feed is positioned at a resonant field maximum.
15. The plasma lamp of claim 13 , wherein the bulb is positioned at a resonant field maximum.
16. The plasma lamp of claim 15 , wherein the first feed is positioned at a different resonant field maximum.