Luminaire having a light guide

Abstract

A luminaire, in particular a downlight, comprises a light source and a reflector, the reflector having a light entrance end and a light exit end, the light entrance end comprising at least one light entrance aperture with an edge and the light exit end comprising a light exit aperture. A luminaire shade encompasses the reflector at least partially. A first portion of the light source light is emitted by the reflector through the light exit aperture and a second portion is emitted through the luminaire shade. The light source is an LED. The luminaire includes a light guide arranged near the light entrance aperture between the LED and light exit end so at least some LED light enters into the light guide, the light guide comprising a light-guiding area extending perpendicular to the longitudinal extension of the reflector at least partially beyond the edge of the light entrance aperture.

Claims

1. A luminaire comprising a light source and a reflector, the reflector including a light entrance end and a light exit end, the light entrance end comprising at least one light entrance aperture with an edge and the light exit end comprising a light exit aperture, the luminaire further comprising a luminaire shade which encompasses the reflector at least partially, wherein a first portion of the light of the light source is not emitted through the luminaire shade, but emitted by the reflector through the light exit aperture, and a second portion of the light of the light source is emitted through the luminaire shade, wherein the light source is an LED, the luminaire further comprising a light guide which is separate from the reflector and arranged in the area of the light entrance aperture between the LED and the light exit end such that at least a portion of the light of the LED enters into the light guide, the light guide comprising a light-guiding area which extends in a direction perpendicular to the longitudinal extension of the reflector at least partially beyond the edge of the light entrance aperture, and wherein the light-guiding area extends, with respect to an axial direction defined by said longitudinal extension of the reflector, in front of the light entrance aperture.

2. The luminaire according to claim 1, wherein the light-guiding area has a substantially disc-shaped configuration.

3. The luminaire according to claim 2, wherein the light-guiding area is configured to be apart, at an angle, from the light exit aperture at least section-wise.

4. The luminaire according to claim 1, wherein the light guide comprises a lens area, the lens area guiding a portion of the light into the reflector.

5. The luminaire according to claim 4, wherein the lens area is arranged at least partially in the light entrance aperture.

6. The luminaire according to claim 4, wherein the light guide comprises at least one step between the lens area and the light-guiding area.

7. The luminaire according to claim 4, wherein the lens area has a plano-convex configuration, the plane surface of the plano-convex lens area pointing away from the light exit end of the reflector.

8. The luminaire according to claim 4, wherein the width of the lens area is between 30% and 50% of the width of the light guide.

9. The luminaire according to claim 1, wherein the width of the light guide in one direction amounts to at least 80% of the available width inside the luminaire shade in the area of the light guide.

10. The luminaire according to claim 1, wherein at least a part of the surface of the reflector pointing to the luminaire shade is configured to be reflective.

11. The luminaire according to claim 1, wherein at least a part of the light guide surface has a defined surface structure.

12. The luminaire according to claim 11, wherein the defined surface structure is a pyramid shaped structure.

13. The luminaire according to claim 1, wherein at least a part of the light guide surface is frosted.

14. The luminaire according to claim 13, wherein the frosted part of the light guide surface is formed via sandblasting.

15. The luminaire according to claim 1, wherein the reflector, the luminaire shade and the light guide are configured rotationally symmetrical and, together with the LED, are arranged coaxially relative to the optical axis of the light guide.

16. The luminaire according to claim 1, wherein the reflector is configured as a parabolic reflector.

17. The luminaire according to claim 1, wherein the luminaire shade and the reflector are connected to one another at the light exit end.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An advantageous exemplary embodiment of the present invention will be explained in more detail below by means of drawings. In the drawings:

(2) FIG. 1 shows a schematic cross-sectional view of a luminaire according to the invention,

(3) FIG. 2 shows a cross-section through the light guide of a luminaire according to the invention.

DETAILED DESCRIPTION

(4) In the following description like parts will be designated with like reference numbers. If a drawing includes reference numbers which are not referred to in the associated description of the figures, reference will be made to the preceding or subsequent description of the figures.

(5) The luminaire 1 according to the invention, illustrated in FIG. 1, is designed as a ceiling spotlight, respectively, downlight. The luminaire 1 includes a light source 2, a reflector 3, a luminaire shade 4 as well as a light guide 5. The reflector 3, luminaire shade 4 and light guide 5 are configured to be rotationally symmetrical with respect to the optical axis A of the light guide 5. In the exemplary embodiment shown the light source 2 is formed of several LEDs 6 which are arranged concentrically about the axis A. The LEDs are designed as SMD-LEDs and attached to the housing 7 of the luminaire 1.

(6) The reflector 3 comprises a light entrance aperture 32 at its light entrance end 31. At its light exit end 34 the reflector 3 comprises a light exit aperture 35. A hollow-cylindrical collar region is formed at the edge 33 of the light entrance aperture 32, which extends substantially perpendicular to the light entrance aperture 32 in the direction of the LEDs 6. The reflector 3 is configured to be reflective on its inside 36 and outside 37.

(7) The light guide 5 comprises a light-guiding area 51. The light-guiding area 51 is disc-shaped, and bent relative to the light exit aperture 35. The light-guiding area 51 runs at an angle of approximately 84 relative to the optical axis A. The light guide 5 defines thus a clearance 55 in which the LEDs 6 are arranged. The outer edge 53 of the light guide 5 is angled approximately parallel to the axis A in the direction of the LEDs. This arrangement allows a very great portion of the emitted light of the LEDs 6 to be radiated into the light guide 5. In the center of the light guide 5 same comprises a lens area 52, the light-guiding area 51 merging via a step 54 into the lens area 52. This allows an arrangement of the LEDs 6 particularly close to the light guide 5. The surface 56 of the lens area 52 pointing to the LEDs 6 has a pyramid-shaped surface structure so as to improve the coupling of the light into the light guide. The lens area 52 has a plano-convex shape. The lens area 52 is arranged in the light entrance aperture 32 of the reflector 3. The edge 33 of the light entrance aperture 32 is in contact with the step region 54 of the light guide 5. The lens area 52 fills the whole light entrance aperture 32 of the reflector 3. The light guide 5 is held by the edge 33 of the light entrance aperture 32 in a force-closed manner. The upper side 57 of the light-guiding area 51 is frosted by sandblasting. Thus, the light emitted by the light-guiding area 51 is mixed.

(8) The luminaire shade 4 in the illustrated embodiment is opaque and surrounds the reflector 3 and the light guide 5. Thus, the light emitted through the luminaire shade 4 is diffuse.

(9) The light emitted by the LEDs 6 is partially coupled through the pyramid-shaped surface structure 56 into the lens area 52, but partially also directly into the light-guiding area 51. A first portion of the coupled light is guided through the lens area 52 into the reflector 3, and emitted by the reflector 3 upwardly. A second portion is guided through the light-guiding area 51 radially outwardly, and is emitted through the frosted surface 57. This portion of the light is thereupon diffusely emitted to the outside through the luminaire shade 4, whereby it may be reflected once again on the outside 37 of the reflector 3 before.

(10) In the embodiment shown the width B of the lens area 52 amounts to approximately 34% of the width C of the light guide 5. The luminaire shade 4 is cylindrical and has a thread 41 on the bottom side thereof. The width C of the light guide 5 amounts to more than 95% of the available width D inside the luminaire shade, whereby the available width corresponds to the inner diameter D of the luminaire shade 4 in the region of the thread 41. The reflector 3 is connected at its light exit aperture 34 to the luminaire shade 4.

(11) In the embodiment shown the luminaire 1 comprises a cylindrical housing 7 which is screw-connected to the luminaire shade 4. A gasket 8 is arranged in the region of the screw connection between the housing 7 and the luminaire shade 4.

(12) For mounting the luminaire 1, firstly the lens area 52 of the light guide 5 is clamped into the light entrance aperture 32 of the reflector 3. The reflector 3 is thereupon connected to the luminaire shade 4 at the light exit aperture 35. Lastly, the luminaire shade 4 is screwed to the housing 7.

(13) FIG. 2 illustrates the light guide of the luminaire according to the invention illustrated in FIG. 1 in more detail.