Method and apparatus for starting difficult to start electrodeless lamps using a field emission source

An excimer lamp, comprising:

• a) an electrodeless envelope including an excimer forming fill;
• b) an external starting electrode switchable between a lamp starting mode where said starting electrode is in proximity to a given region of said envelope, and a lamp operating mode where said starting electrode is disposed away from said given region;
• c) a substance contained in said envelope at said given region for facilitating the starting of the lamp, said substance containing an element selected from the group of cesium, sodium, potassium, and rubidium;
• d) starting power source coupled to said electrode in said lamp starting mode to cause application of an electric field to said substance, said substance being responsive to said electric field to initiate electron emission therefrom to thereby cause a discharge in said fill;
• and
• e) excitation power source coupled to said fill to sustain the discharge.

A microwave powered electrodeless lamp, comprising:

• a) a microwave cavity;
• b) an envelope disposed in said cavity and containing a discharge forming fill;
• c) a metallic probe movable from a first position where said probe is in contact with said envelope at a given region to a second position where said probe is away from said envelope, said probe being in said first position when said lamp is started, said probe being in said second position when said lamp is operating;
• d) a substance contained on an interior surface of said envelope at said given region for facilitating the starting of the lamp;
• e) starting power source coupled to said probe in said first position to cause application of an electric field to said substance, said substance being responsive to said electric field to initiate electron emission therefrom to thereby cause discharge within said fill;
• f) microwave power source coupled to said cavity to sustain the discharge;
• and
• g) dielectric disposed between said probe and said cavity, said dielectric having a dielectric strength greater than the dielectric strength of air.

An electrodeless lamp, comprising:

• a) an envelope containing a fill;
• b) a starting electrode in proximity to a given region of said envelope when the lamp is started;
• c) a field emission source disposed inside said envelope at said given region;
• d) starting power source coupled to said electrode for applying an electric field to said field emission source to cause field emission from said source, said field emission source being responsive to said electric field to initiate electron emission therefrom to thereby cause a discharge within said envelope;
• and
• e) excitation power source coupled to said fill to sustain the discharge.

A method for starting an electrodeless lamp, comprising the steps of:

• a) providing a bulb comprised of an envelope and a discharge forming fill in said envelope;
• b) providing a field emission source on an interior surface of said envelope at a given region;
• c) applying an electric field at said given region to said field emission source, said field emission source being responsive to the electric field to initiate electron emission therefrom to thereby cause a discharge in said fill;
• and
• d) coupling a power source to said fill to sustain the discharge.