LED light bulb

[0001] The present invention relates generally to LED (light emitting diode) light bulbs, and more specifically to an LED light bulb that includes a reflector, which reflects light outwards from LEDs mounted in the light bulb.

[0002] As is well known in the art, different kinds of light bulbs have been developed in addition to the familiar incandescent light bulb, such as halogen lights, florescent lights and LED (light emitting diode) lights. Halogen lights have some disadvantages, such as high temperatures and relatively high wattage.

[0003] LED light bulbs have several advantages. For example, white LEDs have been developed that will last up to 50,000 hours, about 50 times as long as a 60-watt bulb. LED light bulbs are advantageous in places where changing bulbs is difficult or expensive (e.g., hard to reach places, such as the exterior of buildings). Hotels may use LEDs to save costs of replacing burned-out incandescent bulbs.

[0004] Although a LED requires minute amounts of electricity, generates little heat, and transmits a focused beam of light, there is a recognized problem of gathering enough light so that the LED light can compete with an incandescent, halogen or even a florescent light.

[0005] The prior art has recognized the need for focusing light from LEDs to solve the above problem. For example, some LED light bulbs place the LED in a cup shaped mirrored cavity to focus and intensify the light. U.S. Pat. No. 6,840,654 to Guerrieri, et al. describes an LED light bulb with a conical reflecting chamber and a rear housing to accommodate a series of light emitting diodes, each diode residing in a chamber adapted therefore.

[0006] U.S. Pat. No. 6,361,190 to McDermott describes a large surface LED lighting device using a single reflecting means to increase the divergence of light.

[0007] PCT published patent application WO 02/14738A1 to Ming describes a combination of a reflector and magnifying lens to increase the brightness and utility of an LED light.

[0008] US Patent Application US2002/0080622 to Pashley et al describes a multifaceted cup assembly to increase the divergence and intensity of an LED light.

[0009] The present invention seeks to provide a novel LED light bulb, as is described more in detail hereinbelow.

[0010] There is thus provided in accordance with an embodiment of the present invention a light emitting diode (LED) light bulb including at least one LED mounted in a light bulb in electrical communication with an electrical contact adapted for connection to an electrical power source, and a refractor/reflector positioned in the light bulb to reflect outwards light rays emanating from the at least one LED, the refractor/reflector including a curved surface concavely curved with respect to the at least one LED. The curved surface of the refractor/reflector may have a parabolic curve.

[0011] In accordance with an embodiment of the present invention the refractor/reflector may have a narrow end and a wide end, the curved surface curving outwards towards the wide end. A plurality of LEDs may be mounted about the narrow end of the refractor/reflector, wherein light emanating from the LEDs is directed onto the curved surface and reflected outwards from the light bulb. Optionally, one or more LEDs may be mounted in the wide end of the refractor/reflector and in electrical communication with an electrical contact adapted for connection to an electrical power source.

[0014] Reference is now made to FIG. 1, which illustrates an LED light bulb 10, constructed and operative in accordance with an embodiment of the present invention.

[0015] The LED light bulb may include one or more LEDs 12 mounted in a light bulb 14 in electrical communication with an electrical contact 16 adapted for connection to an electrical power source (such as mains, not shown). The LED light bulb 10 may be DC powered (e.g., from a battery, 6-12V) or AC powered (e.g., 110-120 or 220-240 VAC) or solar powered (e.g., connected to a solar cell).

[0016] In a preferred embodiment, the LEDs 12 are mounted on a printed circuit board 15 electrically connected to electrical contact 16. In the non-limiting illustrated embodiment, electrical contact 16 is a standard screw base contact. However, the invention is not limited to this type of contact, and LED light bulb 10 may have any other suitable contact, such as but not limited to, a single pin bayonet base, a double pin bayonet base (with one negative and one positive terminal in the base to match two contact points in a corresponding socket), a flange base, an MR16 socket base, or a wired connection.

[0017] A refractor/reflector 18 may be positioned in the light bulb 14 to reflect outwards light rays emanating from the LEDs 12. The refractor/reflector 18 has a curved surface 20 concavely curved with respect to the LEDs 12. The curved surface 20 may be white, for example. “White” is defined as the color that has no or little hue, due to the reflection of all or almost all incident light. “White” in the specification and claims encompasses, bright white, “dirty” white, off-white, gray-white, snow white, hard-boiled-egg white and other shades of white. Alternatively, the curved surface 20 may be silvered or have a mirror finish (mirrored). The curved surface 20 of the refractor/reflector 18 may be, without limitation, a parabolic curve or a tulip-shaped curve, for example. The periphery of the curved surface 20 about its longitudinal axis may be smooth and round (e.g., conical). Alternatively, the curved surface 20 may be prismatic, that is, have facets about its longitudinal axis.

[0018] In the non-limiting illustrated embodiment, the refractor/reflector 18 has a narrow end 22 and a wide end 24. The curved surface 20 curves outwards towards the wide end 24. A plurality of LEDs 12 are mounted about the narrow end 22 of the refractor/reflector 18, wherein light emanating from the LEDs 12 is directed onto the curved surface 20 and reflected outwards (e.g., horizontally, omnidirectionally 360°) from the light bulb 14.

[0019] The refractor/reflector 18 is shown with the wide end 24 facing upwards to the top part of the light bulb 14 (opposite electrical contact 16), but the invention also encompasses the opposite, wherein the curved surface 20 faces downwards or anything in-between.

[0020] Optionally, one or more LEDs 12 may be mounted in the wide end 24 of the refractor/reflector 18. These LEDs 12 may be in electrical communication with an electrical contact (e.g., the same electrical contact 16 or a different one), such as being mounted on a PCB 28 or similar substrate which is wired to the electrical contact 16.

[0021] The LEDs 12 may be arranged in any pattern, such as but not limited to, a circular pattern or matrix pattern. The LEDs 12 may be of any size, mcd rating, and color (e.g., white, red, green, blue, yellow or other non-white colors, or a RGB (red, green, blue) changing LED, or any combination thereof). Light bulb 14 may be transparent or translucent (or anything between), and may have any size, shape and color.

[0022] It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the features described hereinabove as well as modifications and variations thereof which would occur to a person of skill in the art upon reading the foregoing description and which are not in the prior art.