Optical system for a fresnel lens light, especially for a spotlight or floodlight

• US 20030063466A1
• Filed: 03/13/2002
• Published: 04/03/2003
• Est. Priority Date: 03/16/2001
• Status: Active Grant

• Current Assignee: Auer Lighting GmbH (Saratoga Lighting Holdings LLC)
• Original Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Inventors: Wagener, Harry, Kittelmann, Ruediger
• Granted Patent: US 6,899,451 B2
• Time in Patent Office: Days
• US Class Current: 362/296
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 14/02 by movement of light sources in vehicle head lamps F21S41/657
• CPC Class Codes: F21V 5/045 the lens having discontinuous faces, e.g. Fresnel lenses
• CPC Class Codes: F21V 7/24 characterised by the material
• CPC Class Codes: F21W 2131/406 for theatres, stages or film studios

Abstract

The optical system for the Fresnel lens light has an ellipsoidal reflector (1), a light source (2) and a Fresnel lens (3). The distance (a) between the Fresnel lens (3) and the reflector (1) is related to the distance (b) between the light source (2) and the reflector (1) and is determined by the selected aperture angle for the propagated light beam, e.g. to provide spotlight or floodlight. The distance (b) is adjusted by moving the light source (2) from a first focal point (F1) in a direction toward or away from the vertex (V) of the reflector (1). The ellipsoidal reflector (1) is made of a metallic material or a transparent material. At least one of the respective surfaces on opposite sides of the reflector has a number of thin layers. Surfaces of the at least one Fresnel lens and/or the reflector can be structured to provide more uniform illumination of a given area. The optical system is useful for lights for film, stage, studio and photography.

Claims

1. An optical system for a Fresnel lens light, said optical system comprising an ellipsoidal reflector (10), a light source (2) and at least one Fresnel lens (3), wherein a distance (a) between said at least one Fresnel lens (3) and said ellipsoidal reflector (1) is related to a distance (b) between said light source (2) and said ellipsoidal reflector (1) according to a predetermined relationship and is determined by a predetermined aperture angle for a propagated light beam of the Fresnel lens light.

2. The optical system as defined in claim 1, wherein said distance (b) is set by moving said light source (2) toward or away from a vertex (V) of said ellipsoidal reflector (1).

3. The optical system as defined in claim 1, wherein said ellipsoidal reflector (1) comprises a metallic material or a transparent material.

4. The optical system as defined in claim 3, wherein said ellipsoidal reflector (1) has respective surfaces on opposite sides thereof and at least one of said respective surfaces is provided with a plurality of thin layers.

5. The optical system as defined in claim 4, wherein one of said respective surfaces of said ellipsoid reflector faces said at least one Fresnel lens and is a light-reflecting surface, said light-reflecting surface is structured to scatter incident light and no, one or two surfaces of said at least one Fresnel lens are structured to scatter light that falls on said at least one Fresnel lens.

6. The optical system as defined in claim 4, wherein one of said respective surfaces of said ellipsoidal reflector faces said at least one Fresnel lens is a light-reflecting surface, said light-reflecting surface does not scatter incident light and is not structured to scatter said incident light and at least one surface of said at least one Fresnel lens is structured to scatter light that falls on said at least one Fresnel lens.

7. The optical system as defined in claim 2, wherein said ellipsoidal reflector (1) has a first focal point (F1) closest to said vertex (V) and a second focal point (F2) furthest from said vertex (V), said light source (2) has a filament and said predetermined relationship is such that said light source is positioned so that said filament is located at said first focal point (F1) and said second focal point (F2) coincides with a focal point (F3) of said at least one Fresnel lens so as to provide a spotlight.

8. The optical system as defined in claim 2, wherein said ellipsoidal reflector (1) has a first focal point (F1) closest to said vertex (V) and a second focal point (F2) furthest from said vertex (V), said light source (2) has a filament and said predetermined relationship is such that said light source is positioned so that said filament is positioned closer to said at least one Fresnel lens (3) than said first focal point (F1) and said second focal point (F2) is closer to said at least one Fresnel lens (3) than a focal point (F3) of said at least one Fresnel lens so as to provide floodlight.

9. A Fresnel lens light for film, stage, studio or photography, wherein said Fresnel lens light comprises an optical system including an ellipsoidal reflector (10), a light source (2) and at least one Fresnel lens (3), wherein a distance (a) between said at least one Fresnel lens (3) and said ellipsoidal reflector (1) is related to a distance (b) between said light source (2) and said ellipsoidal reflector (1) according to a predetermined relationship determined by a predetermined aperture angle for a propagated light beam of the Fresnel lens light.

10. The Fresnel lens light as defined in claim 9, wherein said ellipsoidal reflector (1) has a first focal point (F1) closest to said vertex (V) and a second focal point (F2) furthest from said vertex (V), said light source (2) has a filament and said predetermined relationship is such that said light source is positioned so that said filament is located at said first focal point (F1) and said second focal point (F2) coincides with a focal point (F3) of said at least one Fresnel lens so as to provide spotlight.

11. The Fresnel lens light as defined in claim 9, wherein said ellipsoidal reflector (1) has a first focal point (F1) closest to said vertex (V) and a second focal point (F2) furthest from said vertex (V), said light source (2) has a filament and said predetermined relationship is such that said light source is positioned so that said filament is positioned closer to said at least one Fresnel lens (3) than said first focal point (F1) and said second focal point (F2) is closer to said at least one Fresnel lens (3) than a focal point (F3) of said at least one Fresnel lens so as to provide floodlight.

12. The Fresnel lens light as defined in claim 9, wherein said ellipsoidal reflector (1) has respective surfaces on opposite sides thereof and at least one of said respective surfaces is provided with a plurality of thin layers.

13. The Fresnel lens light as defined in claim 12, wherein one of said respective surfaces of said ellipsoid reflector faces said at least one Fresnel lens and is a light-reflecting surface, said light-reflecting surface is structured to scatter incident light and no, one or two surfaces of said at least one Fresnel lens are structured to scatter light that falls on said at least one Fresnel lens.

14. The Fresnel lens light as defined in claim 12, wherein one of said surfaces of said ellipsoidal reflector faces said at least one Fresnel lens is a light-reflecting surface, said light-reflecting surface does not scatter incident light and is not structured to scatter said incident light and at least one surface of said at least one Fresnel lens is structured to scatter light that falls on said at least one Fresnel lens.