Electrodeless fluorescent lamp with an electrically conductive coating

• US 5,808,414 A
• Filed: 03/20/1995
• Issued: 09/15/1998
• Est. Priority Date: 03/18/1994
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Wharmby, David Osborn, Girach, Mohamed Hanif
• Primary Examiner(s): Patel, Ashok
• Application Number:
  US08/407,531
• Time in Patent Office: 1,275 Days
• Field of Search: 313/635, 313/607, 313/160, 313/161, 313/594, 313/234, 315/248, 315/344, 315/338, 315/347, 315/348, 315/70
• US Class Current: 313/607
• CPC Class Codes: H01J 61/28 Means for producing, introducing, or replenishing gas or vapour during operation of the lamp
• CPC Class Codes: H01J 61/35 provided with coatings on the walls thereof; Selection of materials for the coatings using coloured coatings H01J61/40; using luminescent coatings H01J61/42
• CPC Class Codes: H01J 61/56 One or more circuit elements structurally associated with the lamp
• CPC Class Codes: H01J 61/70 Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr
• CPC Class Codes: H01J 65/048 the field being produced by using an excitation coil
• CPC Class Codes: H05B 41/24 in which the lamp is fed by high frequency ac, or with separate oscillator frequencyH05B41/26 takes precedence

Abstract

An electrodeless fluorescent lamp having a lamp envelope with an inner phosphor coating and containing a fill capable of sustaining a discharge when suitably excited by an electric field includes an electrically conductive coating on the exterior of the lamp envelope. The electrically conductive coating is also light transmissive and is effective for confining the electric field to within the lamp envelope.

Claims

1. An electrodeless fluorescent lamp comprising a sealed lamp envelope containing a luminescent layer and a fill capable of sustaining a discharge when suitably excited by an electric field, and a coating, on the external surface of the envelope, of electrically conductive light transmissive material for confining the electric field within the envelope and a light transmissive coating of electrically insulating material over said electrically conductive coating.

2. A lamp according to claim 1, further comprising means for producing the said electric field.

3. A lamp according to claim 2 wherein the field producing means is mains powered and further comprising a mains decoupling capacitor electrically connected to the said external electrically conductive coating.

4. A lamp according to claim 1 wherein said coating is comprised of fluorine doped tin oxide.

5. An electrodeless fluorescent lamp comprising:

a sealed lamp envelope containing a luminescent layer and a fill capable of sustaining a discharge when suitably excited by an RF electric field;

means for producing the electric field;

a coating on the external surface of the envelope, of electrically conductive light transmissive material for confining the electric field within the envelope;

a light transmissive coating of electrically insulating material over said coating of electrical conductive material; and

means for coupling the coating to an RF ground of the field producing means.

6. A lamp according to claim 5 wherein the field producing means is mains powered, and comprising safety means for preventing any contact surface of the lamp from being at mains potential.

7. A lamp according to claim 6 wherein a mains decoupling capacitor is electrically interconnected between the coating of electrically conductive material and said RF ground and provides both the means for coupling the coating to an RF ground and the safety means.

8. A lamp according to claim 6 wherein the means for coupling the coating to an RF ground comprises a decoupling capacitor.

9. A lamp according to claim 5 wherein the said means for coupling the coating to an RF ground comprises a conductive connection of the coating to the said RF ground.

10. A lamp of claim 5 wherein said coating is comprised of fluorine doped tin oxide.