Omnidirectional LED based solid state lamp

• US 8,757,836 B2
• Filed: 01/13/2011
• Issued: 06/24/2014
• Est. Priority Date: 01/13/2011
• Status: Active Grant

• Current Assignee: GE Lighting Solutions LLC (Savant Systems, LLC)
• Original Assignee: GE Lighting Solutions LLC (Savant Systems, LLC)
• Inventors: Kolodin, Boris, Kuenzler, Glenn H., Allen, Gary R., Mayer, Mark J., Cao, Yiyu
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): Snyder, Zachary J
• Application Number:
  US13/005,970
• Publication Number:
  US 20120182711A1
• Time in Patent Office: 1,258 Days
• Field of Search: 362/84, 362/249.02, 362/800
• US Class Current: 362/249.02
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21S 4/00 Lighting devices or systems using a string or strip of light sources
• CPC Class Codes: F21V 29/51 using condensation or evaporation of a fluid, e.g. heat pipes
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 3/061 the material being glass
• CPC Class Codes: F21V 3/062 the material being plastics
• CPC Class Codes: F21V 3/10 characterised by coatings
• CPC Class Codes: F21V 3/12 the coatings comprising photoluminescent substances
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21Y 2107/90 on two opposite sides of supports or substrates
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 19/0071 adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source

Abstract

A lighting apparatus includes a bilaterally symmetrical light engine comprising first and second light emitting diode (LED) devices or planar LED device arrays facing opposite directions, and an envelope including phosphor spaced apart from and surrounding the bilaterally symmetrical light engine. The phosphor is effective to convert light emitted by the light engine to emission light. The bilaterally symmetrical light engine may be configured to emit light having a bilaterally symmetrical intensity distribution that is uniform except at emission angles within 10° of the symmetry plane of the bilaterally symmetrical light engine. Each of the first and second LED devices or planar LED device arrays may comprise at least one hemispherically emitting LED device including an LED chip and an encapsulant encapsulating the LED chip and shaped to refract light emitted by the LED chip into a uniform distribution over a hemispherical solid angle.

Claims

1. An apparatus comprising:

a light engine comprising first and second light emitting diode (LED) devices or planar LED device arrays arranged to emit light in opposite directions, the light engine being bilaterally symmetric about a symmetry plane with the first LED device or planar LED device array and the second LED device or planar LED device array on opposite sides of the symmetry plane; and

a surrounding spherical envelope including phosphor, the light engine disposed at the center of the surrounding spherical envelope, the phosphor being effective to convert light emitted by the light engine to emission light;

wherein each of the first and second LED devices or planar LED device arrays is configured to emit light having a uniform intensity distribution within plus or minus 20% over all emission angles of a hemisphere except angles within 10°

of the symmetry plane.

2. The apparatus as set forth in claim 1, wherein each of the first and second LED devices or planar LED device arrays comprises:

at least one light emitting diode (LED) chip; and

at least one optical element configured to refract or scatter light from the at least one LED chip into a uniform distribution over a hemispherical solid angle.

3. The apparatus as set forth in claim 2, wherein the at least one optical element comprises:

an encapsulant encapsulating each LED chip and shaped to refract light emitted by the encapsulated LED chip into a uniform distribution over a hemispherical solid angle.

4. The apparatus as set forth in claim 2, wherein the at least one LED chip comprises a planar array of LED chips.

5. The apparatus as set forth in claim 2, wherein the at least one optical element refracts or scatters light emitted by the at least one LED chip into a uniform distribution within plus or minus 20% over a hemispherical solid angle excluding angles within 10°

of the symmetry plane.

6. The apparatus as set forth in claim 1, wherein the light engine emits blue, violet, or ultraviolet light and the phosphor converts the blue, violet, or ultraviolet light emitted by the light engine to white emission light.

7. The apparatus as set forth in claim 1, further comprising a post passing through the surrounding envelope, the light engine being mounted on an end of the post.

17. The apparatus as set forth in claim 3, wherein the encapsulant encapsulating each LED chip and shaped to refract light emitted by the encapsulated LED chip into a uniform distribution over a hemispherical solid angle comprises a cusped encapsulant.

18. The apparatus as set forth in claim 17, wherein the cusped encapsulant includes a convex annular sidewall that is undercut and a concave upper surface.

8. An apparatus comprising:

a bilaterally symmetrical light engine comprising first and second light emitting diode (LED) devices or planar LED device arrays facing opposite directions, each of the first and second LED devices or planar LED device arrays including at least one optical element comprising a cusped encapsulant corresponding to and encapsulating each LED device and cooperating with the LED device or device array to generate a hemispherical light distribution, wherein the bilaterally symmetrical light engine is configured to emit light having a bilaterally symmetrical intensity distribution that is uniform except at emission angles within 10°

of the symmetry plane of the bilaterally symmetrical light engine; and

an envelope including phosphor spaced apart from and surrounding the bilaterally symmetrical light engine, the phosphor being effective to convert light emitted by the light engine to emission light.

9. The apparatus as set forth in claim 8, wherein the bilaterally symmetrical intensity distribution is uniform to within plus or minus 20% except at emission angles within 10°

of the symmetry plane of the bilaterally symmetrical light engine.

10. The apparatus as set forth in claim 8, wherein the envelope comprises a spherical envelope and the bilaterally symmetrical light engine is disposed at a center of the spherical envelope.

11. The apparatus as set forth in claim 8, wherein the bilaterally symmetrical light engine further comprises a support having oppositely facing first and second planar surfaces on which the respective first and second LED devices or planar LED device arrays are disposed.

12. The apparatus as set forth in claim 8, wherein the bilaterally symmetrical light engine comprises precisely two LED devices facing opposite directions.

13. The apparatus as set forth in claim 8, wherein the bilaterally symmetrical light engine comprises first and second planar LED device arrays facing opposite directions, the light engine including no additional LED devices other than the LED devices of the first and second planar LED device arrays.

15. The apparatus as set forth in claim 8, wherein the cusped encapsulant includes a convex annular sidewall that is undercut and a concave upper surface.

14. An apparatus comprising:

a bilaterally symmetrical light engine comprising first and second light emitting diode (LED) devices or planar LED device arrays facing opposite directions and configured to emit light having a bilaterally symmetrical intensity distribution that is uniform within plus or minus 20% over all emission angles of a hemisphere except at emission angles within 10°

of the symmetry plane of the bilaterally symmetrical light engine;

a surrounding envelope including phosphor, the light engine disposed at the center of and spaced apart from the surrounding envelope, the phosphor being effective to convert light emitted by the light engine to emission light; and

a post passing through the surrounding envelope, the bilaterally symmetrical light engine being mounted on an end of the post.

16. An apparatus comprising:

a light engine comprising;

a light emitting diode (LED) device, and

a cusped encapsulant encapsulating the LED device and cooperating with the LED device to generate a hemispherical light distribution, the cusped encapsulant including a convex annular sidewall that is undercut and a concave upper surface, and

a planar substrate on which the LED device and the cusped encapsulant are disposed with the convex annular sidewall undercut proximate to the substrate,

wherein the intensity distribution is uniform to within plus or minus 20% except at emission angles within 10°

of the plane of the planar substrate.