Lighting fixture having Fresnel reflector with high reflection coating thereon

Abstract

Lighting fixture having housing with an open side. A lamp is mounted in the housing and produces rays which pass through the open side. The housing carries an internal reflecting surface for reflecting light rays from the lamp through the open side. The internal reflecting surface includes Fresnel type portions for reflecting light rays from the lamp at high angles through the open side. In certain applications, the open side would be enclosed by a glass enclosure. In order to increase the efficiency of the lighting fixture, an anti-reflection coating can be provided on both sides of the glass enclosure. BACKGROUND OF THE INVENTIONMany different types of lighting fixtures hereto fore have been provided. However in connection with such lighting fixtures there always is a need for increased reflectivity from the reflective portions of the lighting fixture. In addition, there is a further requirement to obtain better control over the direction of the light emitted from the lighting fixture. Therefore there is a need for a new and improved lighting fixture which is more efficient and one which emits more light rays at high angles.SUMMARY OF THE INVENTION AND OBJECTSThe lighting fixture consists of a housing which has an open side. A lamp is mounted in the housing and produces light rays through the open side of the housing. The housing carries an internal reflecting surface for reflecting light rays from the lamp through the open side. The internal reflecting surface includes Fresnel type portions for reflecting light rays at higher angles through the open side. High reflecting coatings are provided on the Fresnel portions to increase the efficiency of the lighting fixture. In certain applications a glass enclosure is provided to cover the open side of the housing. To also increase the efficiency, anti-reflection coatings are provided on both surfaces of the glass enclosure.In general, it is an object of the present invention to provide a lighting fixture in which increased efficiency is obtained by increasing the reflectivity from reflective portions of the lighting fixture.Another object of the invention is to provide a lighting fixture of the above character which is provided with Fresnel type reflecting surfaces for increasing the amount of light which is emitted from the fixture at high angles.Another object of the invention is to provide a lighting fixture of the above character in which it is possible to direct the rays in any desired direction from the light fixture without depending on the overall surface configuration of the reflecting surface.Another object of the invention is to provide a lighting fixture of the above character in which the light emitted at high angles directly from the lamp is increased.Another object of the invention is to provide a lighting fixture of the above character in which it is possible to reduce the profile of the lighting fixture.Another object of the invention is to provide a lighting fixture of the above character which has an increased coefficient of utilization.Additional objects and features of the invention will appear from the following description in which the preferred embodiment are set forth in detail in conjunction with the accompanying drawings.

Description

Claims

1. In a lighting fixture, a housing having an open side, a lamp mounted in the housing and producing light rays passing through the open side, an internal reflecting surface carried by the housing for reflecting light rays from the lamp through the open side, said internal reflecting surface including Fresnel type portions positioned so that there is provided a Fresnel type of reflector for reflecting light rays at higher angles of 70.degree. or greater through the open side of the housing by a single reflection of each light ray.

2. A fixture as in claim 1 together with an enclosure covering said open side, said enclosure having planar inner and outer surfaces and a high angle anti-reflection coating disposed on each of the surfaces.

3. A lighting fixture as in claim 2 wherein said reflecting surfaces are generally parabolic.

4. A fixture as in claim 2 wherein said housing is formed of glass and wherein said facets are formed in said glass.

5. A fixture as in claim 4 wherein said glass has a generally parabolic configuration.

6. A fixture as in claim 4 wherein said glass is generally a flat configuration.

7. A fixture as in claim 4 wherein together with a high reflector coating disposed on the facets.

8. A fixture as in claim 7 wherein said high reflector coating is formed of first, second and third layers counting from the surface of the facet with the first layer being formed of a metal and the second and the third layers being formed of materials having low and high indices of refraction respectively.

9. A lighting fixture as in claim 8 wherein said metal layer is formed of aluminum.

10. A lighting fixture as in claim 8 wherein said second layer is formed of a material selected from silicon dioxide and magnesium fluoride.

11. A fixture as in claim 8 wherein said third layer is formed of a material selected from titanium dioxide and zirconium dioxide.

12. A fixture as in claim 1 wherein said Fresnel type reflector surfaces are formed from metal.