Luminaire

• US 6,227,684 B1
• Filed: 04/03/1998
• Issued: 05/08/2001
• Est. Priority Date: 04/07/1997
• Status: Expired due to Term

• Current Assignee: Philips Lighting North America Corporation (Signify N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Entrop, Jean P., Wijbenga, Hendrik
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Zeade, Bertrand
• Application Number:
  US09/054,788
• Time in Patent Office: 1,131 Days
• Field of Search: 362/223, 362/297, 362/300, 362/301, 362/302, 362/346
• US Class Current: 362/310
• CPC Class Codes: F21S 8/02 of recess-mounted type, e.g. downlighters specially adapted for vehicle exteriors F21S41/00-F21S45/00
• CPC Class Codes: F21S 8/024 intended to be recessed in a wall or like vertical structure, e.g. building facade
• CPC Class Codes: F21S 8/026 intended to be recessed in a ceiling or like overhead structure, e.g. suspended ceiling
• CPC Class Codes: F21V 7/09 with a combination of different curvatures
• CPC Class Codes: F21W 2131/101 of tunnels or the like, e.g. under bridges
• CPC Class Codes: F21W 2131/105 of arenas or the like
• CPC Class Codes: F21W 2131/107 of the exterior of buildings

Abstract

The luminaire has a concave reflector (1) with an optical axis (3) in a plane of symmetry (2), suitable to receive an elongate light source transverse to said plane (2). The reflector (1) is composed of flat facets (10,10′) which are bounded by first parallel planes (8) which are transverse to the plane of symmetry (2), and which facets (10,10′) are arranged in rows (11,11′) by second planes (9) which are parallel to the plane of symmetry (2). The first planes (8) are at an acute angle to a light emission window (5). The reflector (1) touches the window (5) at one side of the axis (3) and is extended by a light reflecting screen (7) up to said window (5) at the opposite side of the axis (3). The luminaire can be used to illuminate sports fields, the light emission window (5) being directed downwards, has a sharp cut-off angle and prevents stray light above the horizontal.

Claims

1. A luminaire comprising:

a concave reflector (1) with a plane of symmetry (2) and an optical axis (3) having an optical center (4) lying in said plane (2);

a planar light emission window (5) tangent to the reflector (1) and transverse to the plane of symmetry (2);

means (6) for accommodating an electric lamp transversely to the plane of symmetry (2), with an elongate light source of said lamp in the optical center (4);

a planar light-reflecting screen (7) extending along the optical axis (3) transverse to the plane of symmetry (2);

said reflector (1) comprising several plane facets (10,10′

) bounded by first, mutually substantially parallel, substantially flat planes (8) perpendicular, to the plane of symmetry (2), and having lengths bounded by second substantially flat planes (9) which arrange the facets into rows (11,11′

) which extend along the plane of symmetry(2);

wherein;

the first substantially flat planes (8) enclose an angle of 15°

-30°

with the light emission window (5), and the screen (7) extends from the reflector (1) to the light emission window (5).

2. A luminaire as claimed in claim 1, characterized in that side panels (20) extend up to the screen (7) on either side of the plane of symmetry (2), which panels extend up to in the light emission window (5) and bound facets (10′

) of remote rows (11′

), which rows (11′

) lie farthest removed from the plane of symmetry (2).

3. A luminaire as claimed in claim 2, wherein the screen (7) and the side panels (20) are diffusely reflecting.

4. A luminaire as claimed in claim 2, wherein the side panels (20) approach one another in a direction towards the screen (7).

5. A luminaire as claimed in claim 1, characterized in that the first substantially flat planes (8) have points of intersection (12) with the reflector (1) in the plane of symmetry (2) which lie substantially on a parabola whose focus is the optical center (4).

6. A luminaire as claimed in claim 1, characterized in that the reflector (1) has facets (10) with a greater width w at a side of the optical axis (3) remote from the screen (7) than at a side of this axis (3) adjacent the screen (7).

7. A luminaire as claimed in claim 5, characterized in that the facet (10a) lying closest to the screen (7) in the plane of symmetry (2) is tilted inwards into the parabola along this screen (7).

8. A luminaire as claimed in claim 5, characterized in that the facet (10b) tangent to the light emission window (5) in the plane of symmetry (2) may be tilted outwards from the parabola along the light emission window (5).

9. A luminaire as claimed in claim 5, characterized in that the screen (7) and the optical axis (3) diverge by an angle of a few degrees in a direction towards the light emission window (5).

10. A luminaire as claimed in claim 1, characterized in that the reflector (1) has no more than three rows (11, 11′

) of facets (10, 10′

).

11. A luminaire as claimed in claim 1, characterized in that the second substantially flat planes (9) are substantially parallel to the plane of symmetry (2).

12. A luminaire as claimed in claim 1, characterized in that the facets (10) of a first row (11) intersect the plane of symmetry (2) and, measured in a first flat plane (8), enclose an angle of 35 to 45°

with the facets (10′

) of adjoining rows (11′

).

13. A luminaire as claimed in claim 1, characterized in that the screen (7) is at least substantially parallel to the first substantially flat planes (8).

14. A luminaire as claimed in claim 1, characterized in that the light emission window (5) is closed off by a transparent plate (21).

15. A luminaire as claimed in claim 2, characterized in that the light emission window (5) is closed off by a transparent plate (21), and in that a few slats (22) extend from the light emission window (5) into the luminaire along each of the side panels (20), substantially parallel to the plane of symmetry (2).

16. A luminaire as in claim 1, wherein said first flat planes enclose an angle of 25°

with the light emission window.