System and method for the diffusion of illumination produced by discrete light sources

• US 20050063063A1
• Filed: 07/21/2004
• Published: 03/24/2005
• Est. Priority Date: 07/22/2003
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: TIR Systems Limited (Koninklijke Philips N.V.)
• Inventors: Ashdown, Ian
• Granted Patent: US 7,255,458 B2
• Time in Patent Office: Days
• US Class Current: 359/599
• CPC Class Codes: F21S 4/20 with light sources held by or within elongate supports
• CPC Class Codes: F21V 5/002 using microoptical elements for redirecting or diffusing light
• CPC Class Codes: F21Y 2113/00 Combination of light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G01J 1/04 Optical or mechanical part supplementary adjustable parts
• CPC Class Codes: G01J 1/0474 Diffusers cavities G01J2001/0481
• CPC Class Codes: G01J 1/08 Arrangements of light sources specially adapted for photometry standard sources, also using luminescent or radioactive material
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry

Abstract

The present invention provides a system and method for the diffusion of illumination from discrete light sources such that the illumination is blended and directed in one or more desired directions. The illumination system comprises a substrate having a plurality of light-emitting elements thereon which are arranged in an array, wherein these light-emitting elements produce illumination at one or more wavelengths. Proximate to the light-emitting elements is a diffuser, which collects the illumination produced by the discrete light-emitting elements and redirects this illumination in one or more predetermined directions, thereby blending together the one or more wavelengths of illumination and concentrating the illumination in the predetermined directions. The illumination system further comprises a power system, which provides energy to the light-emitting elements thereby resulting in their activation. Through the blending of the illumination produced by the discrete light-emitting elements together with the redirection of the illumination in a desired direction, both of which are enabled by the diffuser placed proximate to the discrete light-emitting elements, the creation of a blended pattern of illumination from these discrete light-emitting elements is provided, wherein this pattern of illumination can be one or more lines or planes of illumination.

Claims

1. An illumination system comprising:

a) a substrate having a plurality of light-emitting elements thereon, said light-emitting elements arranged in an array and said light-emitting elements producing illumination having one or more wavelengths, said substrate having sides and a length;

b) at least one diffuser proximate to the light-emitting elements, said diffuser collecting the illumination produced by the light-emitting elements and redirecting the illumination in one or more predetermined directions, thereby blending the one or more wavelengths of the illumination and concentrating the illumination in the predetermined directions; and

c) a power system for energising the light-emitting elements and for controlling the illumination produced by the light-emitting elements.

2. The illumination system according to claim 1, wherein said diffuser is a holographic diffuser that produces a linear distribution of the illumination.

3. The illumination system according to claim 2, wherein said diffuser has a cross sectional shape selected from the group comprising flat, round, semicircle and an angular segment.

4. The illumination system according to claim 1, wherein said diffuser is a holographic diffuser that produces a moderately or strongly elliptical distribution of the illumination.

5. The illumination system according to claim 1, wherein the diffuser is a holographic diffuser that diffuses only predetermined wavelengths of the illumination.

6. The illumination system according to claim 1, wherein the diffuser is a replica diffraction grating.

7. The illumination system according to claim 1, wherein the diffuser is a mechanically produced or mastered directional diffuser.

8. The illumination system according to claim 1, wherein the array is a linear array, the one or more predetermined directions are parallel to the linear array and the diffuser has a cross section having a centre of radius intersecting the light emitting elements.

9. The illumination system according to claim 8, wherein the diffuser has a semicircular cross section.

10. The illumination system according to claim 8, wherein the diffuser has an angular segment cross section.

11. The illumination system according to claim 1, further comprising mirrors oriented perpendicular to the substrate and positioned on the sides and along the length of the substrate, said mirrors reflecting portions of the illumination towards the diffuser.

12. The illumination system according to claim 11, wherein said mirrors are flat.

13. The illumination system according to claim 11, wherein said mirrors are curved.

14. The illumination system according to claim 1, further comprising diffraction gratings oriented perpendicular to the substrate and positioned on the sides and along the length of the substrate, said diffraction gratings diffracting portions of the illumination towards the diffuser.

15. The illumination system according to claim 1, further comprising solid objects oriented perpendicular to the substrate and positioned on the sides and along the length of the substrate, said solid objects reflect portions of the illumination towards the diffuser.

16. The illumination system according to claim 1, wherein the array is a linear array and the one or more predetermined directions are tangential to the linear array.

17. The illumination system according to claim 1, wherein the array is a linear array and the one or more predetermined directions are perpendicular to the linear array.

18. The illumination system according to claim 1, further comprising a second diffuser positioned over the diffuser in a stacked configuration, wherein the diffuser and the second diffuser are separated by a predetermined distance.

19. The illumination system according to claim 1, wherein the diffuser is a holographic diffuser having a circular arc cross section having a centre of radius proximate to the light emitting elements.

20. The illumination system according to claim 1, wherein the diffuser is a holographic diffuser having a circular arc cross section having a centre of radius on a side of the diffuser opposite the light-emitting elements.

21. The illumination system according to claim 1, wherein the array is a planar array comprising two or more rows of light emitting elements along the length of the substrate.