OPTICAL ARRANGEMENT

• US 20100053959A1
• Filed: 04/10/2008
• Published: 03/04/2010
• Est. Priority Date: 04/16/2007
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Sabou, Florian Cosmin, Vissenberg, Michel Cornelis Josephus Marie, Ijzerman, Willem Lubertus, Van Der Tempel, Leendert
• Granted Patent: US 8,770,821 B2
• Time in Patent Office: Days
• US Class Current: 362/235
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]

Abstract

An optical arrangement comprising a light guide (101) having a light-entry portion (103) with a light-entry surface (105), a tapering portion (107) with a light reflecting surface, and a light-exit surface (109). The light-entry portion (103) is arranged to guide light from the light-entry surface (105) in a first direction (x) towards the light reflecting surface (H I), the light reflecting surface being arranged in relation to the first direction (x) so that incident light from the light-entry portion (103) is reflected towards the light-exit surface (109). A light transmitting layer (113) is adapted to transmit light diffusively and arranged to cover at least a portion of the light-entry edge surface (105) of the light guide (101). The arrangement is e.g. suitable for use in a LED based luminaire and allows for efficiency and forming of a light beam able to fulfill glare requirements. The arrangement may advantageously be used in a downlighting application.

Claims

1. An optical arrangement comprising:

a light guide (101) having

a light-entry portion (103) with a light-entry surface (105),

a tapering portion (107) with a light reflecting surface (111), and

a light-exit surface (109),

the light-entry portion (103) being arranged to guide light from the light-entry surface (105) in a first direction (x) towards the light reflecting surface (111), the light reflecting surface being arranged in relation to the first direction (x) so that incident light from the light-entry portion (103) is reflected towards the light-exit surface (109); and

a light transmitting layer (113) adapted to transmit light diffusively and arranged to cover at least a portion of the light-entry surface (105) of the light guide (101), wherein the light transmitting layer is a light emitting layer adapted to emit light in response to excitation.

2. The optical arrangement as claimed in claim 1, wherein the light emitting layer is a phosphor layer.

3. The optical arrangement as claimed in claim 1, wherein the optical arrangement further comprises a light source arranged to directly or indirectly illuminate the light transmitting layer and further comprising a re-transmitting light source (115) arranged to illuminate the light transmitting layer (113) in response to illumination by the light source (117).

4. The optical arrangement as claimed in claim 1, wherein the light-entry surface (105) and the light transmitting layer (113) encircle a space (102).

5. The optical arrangement as claimed in claim 1, wherein the light transmitting layer (113) is in optical contact with the light-entry surface (105).

6. The optical arrangement as claimed in claim 1, wherein the light-entry portion (103) increases in thickness from the light-entry surface (105) towards the tapering portion (107).

7. The optical arrangement as claimed in claim 1, further comprising:

a second light guide (153;

157) arranged to guide light to the light transmitting layer (113), said second light guide being adapted to guide light in its interior along a guide direction (y) using reflections in lateral surfaces (155;

159) of the second light guide, which surfaces are substantially parallel to said guide direction (y), the second light guide having a light input area (158) for in-coupling of light and a light output area (168) for output of light to the light transmitting layer (113), wherein the light output area (168) is arranged at a distance from the light input area (158) in the guide direction (y).

8. The optical arrangement as claimed in claim 7, wherein the second light guide (157) is of a dielectric material capable of guiding light inside the material, the light input area and the light output area corresponding to a respective input surface (158) and output surface (168) of said light guide (157).

9. The optical arrangement as claimed in claim 8, wherein the light input area (158) intersects the guide direction (y), and the light input surface (158) is in optical contact with a dielectric medium of lower refractive index, such as air, whereby any light provided to be incident on the light input surface (158) will pass through this medium and be coupled into the second light guide (157) at angles within a determined angular interval that is more narrow than an angular interval of the incident light.

10. The optical arrangement as claimed in claim 8, wherein the light output surface (168) is a portion of one of the lateral surfaces (159), which portion is in optical contact with and at least partially covered by the light transmitting layer (113).

11. The optical arrangement as claimed in claim 8, wherein the light output surface (168) intersects the guide direction (y), the light output surface being in optical contact with a dielectric medium of lower refractive index, such as air, whereby light leaving the second light guide via the light output surface passes through this medium.

12. The optical arrangement as claimed in claim 11, wherein the light output surface (168) is arranged substantially perpendicularly in relation to the light transmitting layer (113).

14. The optical arrangement as claimed in claim 11, wherein the light entry portion (103) comprises a funnel-shaped portion (151) with a wider end of the funnel facing the tapering portion (107) and a narrow end of the funnel comprising the light-entry surface (105).

15. The optical arrangement as claimed in claim 11, wherein all cavity surfaces perpendicular to the light transmitting layer (113) are light output surfaces (168) of the second light guide (157).

17. The optical arrangement as claimed in claim 3, wherein the light source comprises at least one light-emitting diode.

13. (canceled)

16. (canceled)