Illumination apparatus for a fluorescent task lamp
An illumination assembly for a handheld fluorescent task lamp, comprising first and second elongated compact fluorescent bulbs positioned in an upright orientation side by side; a self starting electronic driver circuit operable to start and run the at least first and second compact fluorescent bulbs; and first and second receptacles for connecting the first and second compact fluorescent bulbs to the driver circuit and orienting the first and second compact fluorescent bulbs at a predetermined optimum angle with respect to each other such that an enhanced forward emission field is provided.
1. An illumination assembly for a fluorescent task lamp, comprising:
first and second elongated CFL bulbs having a longitudinal axis and positioned in an upright orientation side by side in the task lamp wherein the first and second CFL bulbs each have a twin tube configuration having first and second parallel emitting tubes;
a power supply controlled by an ON/OFF switch;
a self-starting electronic driver circuit connected to and operated by the power supply and operable to start and run the at least first and second CFL bulbs; and
first and second receptacles for connecting the first and second CFL bulbs to the driver circuit and orienting the first and second CFL bulbs at a predetermined optimum angle of approximately 153 +/−10 degrees with respect to each other such that an enhanced forward emission field is provided.
2. The assembly of claim 1 , wherein the enhanced forward emission field has an intensity defined by the sum of the light emissions from each of the four tubes of the first and second CFL bulbs.
3. The assembly of claim 2 , wherein the enhanced forward emission field is defined substantially within an included angle of approximately 108 degrees.
4. The assembly of claim 1 , wherein the first and second CFL bulbs may be either non-starter type or starter type fluorescent bulbs.
5. The assembly of claim 1 , further comprising a lens surrounding the first and second CFL bulbs and configured for providing both enhanced flood lamp and spotlight emissions.
6. The assembly of claim 5 , wherein the enhanced flood lamp emissions are directed normal to the longitudinal axes of the CFL bulbs.
7. The assembly of claim 5 , wherein the spotlight emission is directed along an axis parallel to the longitudinal axes of the CFL bulbs.
8. The assembly of claim 1 , wherein the first and second receptacles oriented at the predetermined optimum angle are disposed in a common body.
9. The assembly of claim 8 , wherein the predetermined optimum angle is approximately 153 degrees between first and second respective and intersecting planes, each plane passing through and defined by the parallel longitudinal axes of both of the twin tubes of each respective first and second CFL bulb.
10. The assembly of claim 9 , wherein the predetermined optimum angle may vary within a range of plus and minus ten degrees.
11. The assembly of claim 1 , further comprising a reflector having a reflecting surface disposed proximate the first and second CFL bulbs on a side of the first and second CFL bulbs opposite the enhanced forward emission field.
12. The assembly of claim 11 , wherein the reflecting surface is a plane disposed substantially normal to a plane passing between the first and second CFL bulbs and bisecting the forward emission field, and substantially parallel to the longitudinal axes of each tube of the first and second CFL bulbs.
13. The assembly of claim 11 , wherein the reflecting surface is a curved surface having a longitudinal centerline disposed in a plane passing between the first and second CFL bulbs and bisecting the forward emission field, and substantially parallel to the longitudinal axes of each tube of the first and second CFL bulbs.
14. The assembly of claim 13 , wherein the curved surface of the reflector has a cross section that is concave in the direction of the forward emission field.
15. The assembly of claim 14 , wherein the curved surface is cylindrical.
16. The assembly of claim 14 , wherein the curved surface is a conic section.
17. The assembly of claim 13 , wherein the curved surface of the reflector has a cross section that is convex in the direction of the forward emission field.
18. The assembly of claim 17 , wherein the curved surface is cylindrical.
19. The assembly of claim 17 , wherein the curved surface is a conic section.
20. The assembly of claim 1 , wherein the first and second CFL bulbs are oriented such that a centerline of the forward emission of each first and second CFL bulb intersects the centerline of the other CFL bulb at a second predetermined optimum angle.
21. The assembly of claim 20 , wherein the second predetermined optimum angle is approximately 27 degrees.
22. The assembly of claim 20 , wherein the enhanced forward emission field is defined substantially within an included angle called the effective emission beam width of approximately 108 degrees.
23. The assembly of claim 22 , wherein the second predetermined optimum angle is approximately one quarter of the effective beam width, and defines the angle of intersection of the center lines of the forward emission of each first and second CFL bulb.
24. The assembly of claim 23 , wherein the second predetermined optimum angle is approximately 27 degrees.