System for directing light from a luminaire

Details System for directing light from a luminaire System for directing light from a luminaire

2002-08-23

2004-03-16

O'Shea, Sandra (Department: 2875)

Illumination

Elongated source light unit or support

With or including transparent or translucent member

C362S147000, C362S346000, C362S217060, C362S221000, C362S222000, C362S223000, C362S367000

Reexamination Certificate

active

06705742

ABSTRACT:

FIELD OF THE INVENTION
The present invention pertains generally to lighting apparatus. More particularly, the new and useful invention claimed in this document pertains to a system for directing light from a luminaire in a variety of directions to achieve high performance and a number of aesthetic effects. The present invention is particularly, but not exclusively, useful for providing combinations and permutations of direct and indirect lighting.
BACKGROUND OF THE INVENTION
Lighting apparatus and fixtures, commonly referred to in the lighting industry as “luminaires,” are ubiquitous sources of light in modern industrialized nations both in residential, commercial, and other environments. Luminaires are expected to provide not only effective and energy-efficient radiant energy in the form of light, but also ambiance and aesthetics. Indeed, interior and exterior lighting presents at least two persistent challenges, performance and aesthetics.
The term “performance” means and is concerned with qualitative and quantitative aspects of light and lighting, as well as the flexible capability to direct light where lighting is desired. The term “aesthetics” includes not only the ambiance provided by a source of light that makes vision possible, but also the sensation aroused by stimulation of visual receptors. Thus, while it may be interesting from an engineering perspective that light is an electromagnetic radiation in wave length ranges that include infrared, visible, ultraviolet light, as well as x-rays, when traveling in a presumed vacuum at a speed of about 186,281 miles per second, and can be seen or sensed by the human eye, a luminaire is expected to present a pleasant appearance, permit adjustable direction of light that contributes to creating a pleasant mood and ambiance, while also providing useful energy-efficient light where desired. Therefore, a lighting fixture, or luminaire, must provide clean lines, appealing proportions in virtually any environment, problem-free installation and alignment, and years of reliable service. A luminaire also must be efficient, and use the least amount of electricity while achieving the highest performance and the best aesthetics.
Efforts to achieve both high performance and superb aesthetics have induced the industry to manufacture luminaire housings from a wide variety of materials. Smooth and textured coatings for luminaires have been provided. Minimal visible hardware components seek to achieve refined architectural design. In addition, luminaires have been designed to provide uniform output of light, free from streaks and striations. A variety of lamps have been developed in response to the demand for different quantities, qualities and colors of light. Accordingly, modern luminaires may use a variety of lamps, including quartz halogen, compact fluorescent, ceramic metal halide, and metal halide lamps. Microprismatic lenses, white or colored defusing lenses, ultraviolet and colored filters, baffled glare shields, cut off visors and similar apparatus have also been introduced into modern luminaires, also in the continuing effort to achieve both performance and aesthetics. Two patents demonstrating exemplary industry efforts to achieve performance and aesthetics include U.S. Pat. No. Des. 396,321, issued Jul. 21, 1998, and U.S. Pat. No. Des. 396,320, issued Jul. 21, 1998, both issued to one of the co-inventors of the present invention, and assigned to Insight Lighting, Inc.
Considerable efforts also have been devoted to evolving mathematical formulae and calculations to predict lighting performance and aesthetics. One series of formulae, for example, has been developed for determining illumination provided by a particular luminaire when positioned or mounted at a point P
1
. Cubic illumination at P
1
is a function of six illuminances on the faces of a presumed cube, consisting of three opposed pair of illuminances on x, y and z-axes. From such data, an illumination vector E
1
(X,Y,Z) may be determined. It is known that 3-dimensional illuminance distribution at any point in space is the sum of two components, the vector component E
1
and the symmetric component. The vector component and symmetric component together generate illumination patterns that are variations of light and shade formed on the surface of solid objects that intercept a flow of light. For each object, the illumination pattern is the sum of the effects of these two components. Light, therefore, to those who invent, design and manufacture light and lighting fixtures, or luminaires, is thought of at least in part in terms of light and shade patterns, and the sum of effects generated by the vector and symmetric components. It is the combination of light and shade patterns that are vital to visualize illumination.
Of course, quantification aspects of calculating light also is important. “Quantification” is concerned with the quantity of light produced by a given luminaire. Cubic illumination may be determined either by calculation or by measurement of the six cubic illuminances. Illuminance, however, may be applied to two distinctly different types of lighting problems, namely eye illumination, and object illumination. For example, eye illumination may be considered from the point of view of scalar illuminates, or the average illuminance of a small sphere, which is a simple metric that evaluates both light arriving at the eye from all directions, and which provides an indicator of ambient light level in an illuminated space rather than from the perspective of a horizontal plane illuminance.
Reflection, or the return of light waves from a surface, also has considerable impact on both performance and aesthetics of a luminaire. It is known that an incident beam of light may be reflected, or returned, from a smooth surface as a reflected beam, and that the angle the incident beam makes with an imaginary line called the “normal” that is at right angles to the reflection surface equals the angle made by the reflected beam, but on the other side of the normal.
To achieve performance and aesthetics from a luminaire, luminosity also is important. Luminosity is concerned with emitting or reflecting light, usually in the form of a steady, suffused, or glowing light. Reflectance, on the other hand, is concerned with the fraction of the total radiant flux of luminosity that is incident upon a surface that is reflected, and that varies according to the wave length distribution of incident radiation. To determine the quality or quantity of reflectance, the nature of the reflective surface must be known. Some reflective surfaces are specular, having the qualities of a mirror. Orientation of a reflective surface to the source of incident radiation in the form of light also affects reflectance. Diffuse or matte surfaces tend to veil reflections that in turn reduce the range of colors.
Luminance, however, like reflectance, is non-uniform. Furthermore, reflectances are usually demand-set by an architect or interior designer so that lighting or luminance determinations rest on the selection of illuminances. Thus it is clear that altering reflectances in a luminaire will affect performance and aesthetics, those two twin persistent challenges to the inventor and designer of luminaires. In part, these are issues addressed by the present invention.
Conventional luminaires tend to achieve performance without luminosity; or they provide luminosity, but lack performance. In other words, current suggestions for achieving performance and aesthetics from a luminaire solve one problem, but not both. In an indirect luminaire, one from which light is emitted substantially upward or vertically from the luminaire, performance may be achieved in present luminaires without providing fascia glow. Alternatively, in an indirect luminaire, conventional units may provide fascia glow, or luminosity, but unacceptable performance. As used in this document, the term “fascia” generally refers to a variously shaped member that is selected and designed to emit light through the member. Thus, fascia may include a member

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