LED lamp with high color rendering index

• US 9,458,971 B2
• Filed: 05/01/2015
• Issued: 10/04/2016
• Est. Priority Date: 12/22/2010
• Status: Active Grant

• Current Assignee: IDEAL Industries Lighting, LLC (Ideal Industries Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: van de Ven, Antony Paul, Negley, Gerald H., Lu, Dong
• Primary Examiner(s): Guharay, Karabi
• Application Number:
  US14/702,176
• Publication Number:
  US 20150330581A1
• Time in Patent Office: 522 Days
• Field of Search: 362/294, 362/231
• US Class Current: 1/1
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• 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 9/235 Details of bases or caps, i.e. the parts that connect the light source to a fitting; Arrangement of components within bases or caps F21K9/238 takes precedence
• CPC Class Codes: F21K 9/237 Details of housings or cases, i.e. the parts between the light-generating element and the bases; Arrangement of components within housings or cases F21K9/238 takes precedence
• CPC Class Codes: F21K 9/238 Arrangement or mounting of circuit elements integrated in the light source
• CPC Class Codes: F21K 9/272 Details of end parts, i.e. the parts that connect the light source to a fitting; Arrangement of components within end parts F21K9/278 takes precedence
• CPC Class Codes: F21K 9/62 using mixing chambers, e.g. housings with reflective walls
• CPC Class Codes: F21K 9/66 Details of globes or covers forming part of the light source
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: F21K 9/90 Methods of manufacture
• CPC Class Codes: F21V 23/02 the elements being transformers, impedances or power supply units, e.g. a transformer with a rectifier
• CPC Class Codes: F21V 29/51 using condensation or evaporation of a fluid, e.g. heat pipes
• CPC Class Codes: F21V 29/773 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21V 29/83 the elements having apertures, ducts or channels, e.g. heat radiation holes
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21V 3/04 characterised by materials, surface treatments or coatings
• CPC Class Codes: F21V 7/0016 on lighting devices that also provide for direct lighting, e.g. by means of independent light sources, by splitting of the light beam, by switching between both lighting modes
• CPC Class Codes: F21V 7/041 with conical or pyramidal surface
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 : Light-emitting diodes [LED]
• CPC Class Codes: Y10T 29/49002 : Electrical device making
• CPC Class Codes: Y10T 29/49119 : Brush

Abstract

An LED lamp with a high color rendering index (CRI) is disclosed. Example embodiments of the invention provide an LED lamp with a relatively high color rendering index (CRI). In some embodiments, the lamp has other advantageous characteristics, such as good angular uniformity. In some embodiments, the LED lamp is sized and shaped as a replacement for a standard incandescent bulb, and includes an LED assembly with at least first and second LEDs operable to emit light of two different colors. In some embodiments, the lamp can emit light with a color rendering index (CRI) of at least 90 without remote wavelength conversion. In some embodiments, the LED lamp conforms some, most, or all of the product requirements for a 60-watt incandescent replacement for the L prize.

Claims

1. An LED lamp comprising:

an Edison base;

an LED assembly further comprising at least first and second LED device packages that emit light of at least two different colors; and

an optical enclosure around the LED assembly connected to the Edison base to form an A shaped replacement for a standard incandescent light bulb, the optical enclosure comprising a section having a higher transmittance-to-reflectance ratio than most of the optical enclosure;

wherein the optical enclosure and the LED assembly are configured so that light from the LED assembly passes through the optical enclosure without wavelength conversion outside of the LED device packages and is emitted from the lamp with a correlated color temperature (CCT) from 2500K to 3500K that is reduced with dimming to as low as 1200K.

2. The LED lamp of claim 1 wherein the optical enclosure further comprises a color mixing treatment.

3. The LED lamp of claim 1 wherein light is emitted from the lamp with a CCT from 2700K to 3300K.

4. The LED lamp of claim 1 further comprising a power supply connected between the LED assembly and the Edison base.

5. The LED lamp of claim 1 wherein the LED device packages include lumiphors.

6. The LED lamp of claim 5 operable with a luminous efficacy of at least 100 lumens per watt.

7. The LED lamp of claim 5 operable a luminous efficacy of at least 75 lumens per watt.

8. An LED lamp comprising an LED assembly including at least two groups of LED device packages that emit light of at least two different colors, and further comprising an optical enclosure around the LED assembly to form an A shaped replacement for a standard incandescent light bulb, the optical enclosure comprising a section having a higher transmittance-to-reflectance ratio than most of the optical enclosure so that light from the LED assembly is emitted through the optical enclosure without remote wavelength conversion outside of the LED device packages and with a correlated color temperature (CCT) from 2500K to 3500K that is reduced with dimming to as low as 1200K.

9. The LED lamp of claim 8 wherein LEDs in one group of LED device packages LEDs are arranged in two strings with LEDs in the second group of LED device packages are arranged in a single string between the two strings.

10. The LED lamp of claim 9 comprising a support for the LED assembly, wherein the support further comprises at least one of a thermal post, a reflective surface, and a heat pipe.

11. The LED lamp of claim 8 wherein light is emitted from the lamp with a CCT from 2700K to 3300K.

12. The LED lamp of claim 8 wherein the LED device packages include lumiphors.

13. The LED lamp of claim 12 operable with color rendering index (CRI) of at least 90.

14. The LED lamp of claim 13 operable a luminous efficacy of at least 75 lumens per watt.

15. A method of making an LED lamp comprising:

providing at least first and second LED device packages operable to emit light of two different colors, at least some of the LED device packages including a lumiphor to produce an LED assembly that can provide light with a correlated color temperature (CCT) from 2500K to 3500K that is reduced with dimming to as low as 1200K; and

installing an optical enclosure around the LED assembly to form an A shaped replacement for a standard incandescent light bulb, the optical enclosure comprising a section having a higher transmittance-to-reflectance ratio than most of the optical enclosure, and so that at least some light emitted by the LED assembly when the lamp is energized exits the LED lamp through the optical enclosure without wavelength conversion outside of the LED device packages.

16. The method of claim 15 further comprising installing a power supply in the power supply portion to enable the LED lamp.

17. The method of claim 16 further comprising installing a support for the LED assembly, wherein the support is selected from a group consisting of a support with a conical reflective surface, a thermal post, and a heat pipe.

18. The method of claim 16 wherein light is emitted from the LED lamp with a CCT from 2700K to 3300K.

19. The method of claim 16 wherein the LED lamp is operable with a luminous efficacy of at least 100 lumens per watt.

20. The method of claim 16 wherein the luminous efficacy is at least 75 lumens per watt.