LED work light
Work light has LEDs that require heatsink. Desired radiation pattern achieved by using optical components designed to produce beam or LEDs may have beams in different directions. Radiation pattern of LEDs may be changed by refractive-reflective optics or by convex lenses. Convex lenses may be hemispheres, other planoconvex shapes, concavo-convex shapes, or other shapes. Curved surfaces on any lenses may be spherical or aspheric. Ballast to operate the LEDs from line voltage AC or low voltage DC. Work light may contain batteries. The work light may be mounted on a stand. May have accessory mount. May have charging station. May have a paging transmitter to activate a paging receiver in work light. May have openings for heat transfer from heatsink to ambient air external to light.
1. A work light comprising:
a) a high power LED that normally requires a heatsink for operation in a normal working environment while preserving a useful life in prolonged use,
b) a heatsink thermally connected to the LED to preserve useful working life of the LED when operated in prolonged use,
c) a casing substantially enclosing the LED and the heatsink, the casing comprising at least a portion that is transparent through which light can emit from the casing about a beam axis,
d) an optic within the casing associated with the LED such that a beam of light radiating from the LED has a beam width that is changed by the optic, and light emitting from the optic emits a useful beam of light through a transparent portion of the casing, the useful beam of light with a width adequate for use in working for prolonged periods that is essentially at least 40 degrees and essentially no more than 90 degrees,
wherein the casing is substantially tubular and wherein the beam emitted from the casing has a central beam axis that is essentially perpendicular to a longitudinal axis of the casing, and wherein the beam of light emitting from the optic has a more uniform light density across its beam width than the light density across a beam emitted by the LED, and
wherein the optic is a convex lens, the convex lens has both a convex surface and a concave surface, and the concave surface is curved more sharply towards its edge than towards its center such that light is more evenly spread across the area of the beam when the LED associated with the concave surface has a beam width greater than 90 degrees.
2. The work light of claim 1 wherein the concave surface is flat in its center.
3. The work light of claim 1 wherein: the LEDs are white LEDs.
4. The work light of claim 3 further comprising:
a) a plurality of LEDs including the LED,
b) a plurality of optics including the optic, and
c) at least one heatsink including the heatsink,
wherein each optic is associated with a respective one of the LEDs, and each LED is thermally connected to the at least one heatsink, and
wherein each LED produces a beam of light having a beam width other than essentially at least 40 degrees and essentially no more than 90 degrees,
wherein the plurality of LEDs and optics are arranged to produce a combined work light beam having a beam width that is essentially at least 40 degrees and essentially no more than 90 degrees,
wherein the beam of light emitting from each optic has a more uniform light density across its beam width than the light density across a beam emitted by its associated LED, and
wherein each LED of the plurality of LEDs produces a beam of light having a beam width of essentially less than 40 degrees and each optic is placed forward from its respective LED in order for said work light to produce a work light beam width that is essentially more than 40 degrees and essentially no more than 90 degrees, and
wherein each optic is a convex lens, each convex lens has both a convex surface and a concave surface, and the concave surface is curved more sharply towards its edge than towards its center such that light is more evenly spread across the area of the beam when the LED associated with the concave surface has a beam width greater than 90 degrees.
5. The work light of claim 4 wherein: said work light works from low voltage direct current.
6. The work light of claim 5 further comprising: a DC power source within the casing.
7. The work light of claim 5 wherein: the DC power source comprises rechargeable batteries.
8. The work light of claim 7 wherein: the casing is plastic.
9. The work light of claim 8 further comprising: a handle covering about a handle portion of the casing extending from a head portion of the casing, wherein the head portion houses the LED and heatsink.
10. The work light of claim 9 wherein: the handle covering comprises a compressible material.
11. The work light of claim 10 wherein: the compressible material is selected from rubber or a thermoplastic elastomer.
12. The work light of claim 4 wherein: at least one convex lens is part of a transparent lens assembly.
13. The work light of claim 12 wherein: the transparent lens assembly is molded.
14. The work light of claim 13 wherein: the lens assembly is machined after molding.
15. The work light of claim 14 wherein: the lens assembly is polished after machining.
16. The work light of claim 4 wherein the convex surface of each convex lens has a diameter, and the concave surface of each convex lens has a diameter smaller than that of the convex surface of its respective convex lens.
17. The work light of claim 4 wherein the concave surface of each convex lens is flat in its center.
18. The work light of claim 4 wherein: the plurality of LEDs are mounted substantially on one plane to emit light substantially perpendicular to the plane.
19. The work light of claim 18 wherein: the plurality of LEDs are mounted substantially along a line in the plane.
20. The work light of claim 4 wherein: dissipation of heat from the at least one heatsink maintains the temperature of an outside surface of the LEDs below about 75 degrees Celsius in a range of ambient temperatures below about 35 degrees Celsius.
21. The work light of claim 20 wherein the at least one heatsink is set back from an adjacent internal surface of the casing.
22. The work light of claim 20 further comprising: an air gap between the at least one heatsink and the adjacent internal surface of the casing.
23. The work light of claim 20 wherein each LED emits light about a central beam axis,
wherein the at least one heatsink has three dimensions: depth, width and height,
wherein each LED is mounted adjacent and in thermal contact with the at least one heatsink along the respective LED central beam axis in an opposite direction to which the LED emits light,
wherein the depth of the at least one heatsink is measured along the respective LED central beam axis,
wherein the width and height of the at least one heatsink are measured perpendicular to the depth and to one another, and
wherein the depth of the at least one heatsink is substantially less than the width of the at least one heatsink and substantially less than the height of the at least one heatsink, such that the work light uses less space in the direction in which light is desired.
24. The work light of claim 4 , wherein each LED has a nominally lambertian radiation pattern.