Directional lamp with beam forming optical system including a lens and collecting reflector

Patent metadata

Field	Value
Publication number	US-9534743-B2
Application number	US-201314083597-A
Country	US
Kind code	B2
Filing date	Nov 19, 2013
Priority date	Jan 11, 2010
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A directional lamp comprises a light source, a beam forming optical system configured to form light from the light source into a light beam, and a light mixing diffuser arranged to diffuse the light beam. The light source, beam forming optical system, and light mixing diffuser are secured together as a unitary lamp. The beam forming optical system includes: a collecting reflector having an entrance aperture receiving light from the light source and an exit aperture that is larger than the entrance aperture, and a lens disposed at the exit aperture of the collecting reflector, the light source being positioned along an optical axis of the beam forming optical system at a distance from the lens that is within plus or minus ten percent of a focal length of the lens.

First claim

The invention claimed is:

1. A directional lamp comprising:
a planar light source comprising one or more light emitting diode (LED) devices defining an LED plane; and
a beam forming optical system configured to form light from the planar light source into a light beam, the optical system including:
a collecting reflector having an entrance aperture of diameter D s receiving light from the light source and an exit aperture of diameter D o that is larger than the diameter D s of the entrance aperture, and
a collimating lens disposed at the exit aperture of the collecting reflector; and
wherein the light source and beam forming optical system are secured together as a unitary lamp.

2. The directional lamp as set forth in claim 1 , further comprising a light-mixing diffuser arranged to diffuse the light beam wherein the light mixing diffuser comprises a single-pass diffuser having less than 10% back-reflection for the light beam.

3. The directional lamp as set forth in claim 2 , wherein the single-pass diffuser comprises an interlace diffuser.

4. The directional lamp as set forth in claim 2 , wherein the single-pass diffuser scatters collimated input light into an angular distribution having a full width at half maximum (FWHM) of less than or about 40°.

5. The directional lamp as set forth in claim 1 , further comprising a light-mixing diffuser arranged to diffuse the light beam wherein the light mixing diffuser comprises an interface diffuser formed into a principal surface of the collimating lens of the beam forming optical system.

6. The directional lamp as set forth in claim 1 , further comprising a light-mixing diffuser arranged to diffuse the light beam wherein the light mixing diffuser is disposed to receive light from the light source after passing through the collimating lens.

7. The directional lamp as set forth in claim 1 , wherein the planar light source is positioned along an optical axis of the beam forming optical system with the LED plane at a distance from the collimating lens that is within plus or minus ten percent of a focal length of the collimating lens.

8. The directional lamp as set forth in claim 1 , wherein the one or more LED devices include LED devices of at least two different colors, and the directional lamp further comprises a light mixing diffuser arranged to diffuse the light beam to reduce the variation of chromaticity within the FWHM beam angle to within 0.006 from the weighted average point on the CIE 1976 u′v′ color space diagram.

9. The directional lamp as set forth in claim 1 , wherein θ s is the half-angle of light emission of the planar light source, θ o is the half-angle of light emission of the directional lamp, and

D
o

≥

θ
s

θ
o

⁢

D
s

⁢

⁢

⁢
and
⁢

⁢

D
s

≤

θ
o

θ
s

⁢

D
o

.

10. The directional lamp as set forth in claim 9 , wherein:
the light source is positioned along the optical axis of the beam forming optical system at a defocused position respective to the collimating lens to produce defocusing, and
the directional lamp further comprises a light mixing diffuser arranged to diffuse the light beam, wherein diffusion of the light beam provided by the light mixing diffuser together with the defocusing transforms a spatial intensity distribution of the light beam having multiple intensity peaks due to the plurality of spatially discrete light emitting elements into a light beam having no visually perceptible local variations of intensity throughout the beam pattern.

11. The directional lamp as set forth in claim 1 , further comprising:
a first diffuser disposed with the planar light source at the entrance aperture of the collecting reflector; and
a second diffuser disposed with the collimating lens at the exit aperture of the collecting reflector.

12. The directional lamp as set forth in claim 1 , wherein θ s is the half-angle of light emission of the planar light source, θ o is the half-angle of light emission of the directional lamp, and

D
o

≥

θ
s

θ
o

⁢

D
s

⁢

⁢

⁢
and
⁢

⁢

D
s

≤

θ
o

θ
s

⁢

D
o

,

and the planar light source is positioned along an optical axis of the beam forming optical system with the LED plane at a distance from the collimating lens that is within plus or minus ten percent of a focal length of the collimating lens.

13. The directional lamp as set forth in claim 1 , wherein the collimating lens has an f-number N=f/D of less than or about one where f is the focal length of the collimating lens and D is a maximum dimension of the entrance pupil of the collimating lens.

14. The directional lamp as set forth in claim 13 , wherein the planar light source is positioned along an optical axis of the beam forming optical system with the LED plane at a distance from the collimating lens that is within plus or minus ten percent of a focal length of the collimating lens.

15. The directional lamp as set forth in claim 1 , wherein the planar light source is positioned along an opti

Assignees

• Allen Gary R
• Weaver Jr Stanton E
• Mulder R Stephen
• Dudik David C
• Kaminski Mark E
• Ge Lighting Solutions Llc

Inventors

• Allen Gary R
• Weaver Jr Stanton E
• Mulder R Stephen
• Dudik David C
• Kaminski Mark E

Classifications

• F21Y2105/10

  comprising a two-dimensional [2D] array of point-like light-generating elements · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• F21V5/04

  of lens shape · CPC title

• F21K9/60

  Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction · CPC title

• F21Y2105/12

  characterised by the geometrical disposition of the light-generating elements, e.g. arranging light-generating elements in differing patterns or densities · CPC title