Illumination – Housing – Recessed
Reexamination Certificate
1999-06-30
2001-06-26
Quach, Y. (Department: 2875)
Illumination
Housing
Recessed
C362S147000, C362S339000, C362S348000
Reexamination Certificate
active
06250780
ABSTRACT:
TECHNICAL FIELD
This invention relates to an indoor luminaire assembly or lighting unit.
BACKGROUND ART
Designers of lighting for recessed indoor applications have limited design choices. This is particularly the case when the designer desires a smaller lighting fixture package because the designated recessed lighting environment has a high grid ceiling or a shallow plenum depth between ceiling and adjacent floor joists. Traditionally, fluorescent lighting fixtures have been used in such recessed applications because they generate much less heat than other types of lighting units (such as high intensity discharge luminaires), making them ideal for placement in a high ceiling having a shallow plenum depth. Fluorescent fixtures also typically have horizontally oriented lamps which lie in the plane of the ceiling, usually because any other orientation would lead to visual discomfort and glare due to direct high angle radiation from the lamp, and may require louvers. However, fluorescent fixtures also provide relatively less illumination than other types of lighting fixtures, thereby requiring a greater number of units to achieve the desired lighting effect.
Another type of lighting unit is the high intensity discharge (HID) luminaire, which is often used in outdoor applications. HID units have generally proven unsuitable for indoor applications as they tend to generate a relatively large and undesirable amount of heat, especially in the context of enclosed spaces, such as a grid ceiling, and particularly in those ceilings having a relatively shallow plenum depth. Such fixtures also produce unacceptable glare.
Accordingly, when used indoors, such luminaires have generally used a white coated diffuse reflector and a flat prismatic lens (which lies in the ceiling plane) to help reduce the apparent brightness of the fixture. Unfortunately, the diffuse nature of this type of reflector causes a large reduction in reflector efficiency. Also, the radiant energy emitted by the HID lamp goes through multiple reflection bounces before it exits the luminaire. Because each reflection leads to some degree of absorption of radiation (for example, if reflectance is 80%, then the material absorbs 20% of the energy), this leads to more energy being absorbed by the luminaire housing and hence transmitted to the ceiling structure in the form of heat. Moreover, in traditional HID fixtures, in order to change the lighting distribution it is necessary to change the lamp center and/or the optical unit itself, which can be a time consuming and costly task.
Consequently, an improved luminaire assembly for indoor applications is desired. The improved luminaire assembly should be adapted for use in a high grid ceiling or a ceiling having a shallow plenum depth. The luminaire assembly should have acceptable levels of generated and absorbed heat, brightness and glare control for their designated application. The luminaire should also have relatively high efficiency and reflectance.
DISCLOSURE OF INVENTION
It is an object according to the present invention to provide an improved luminaire assembly for indoor applications.
It is a further object according to the present invention to provide an improved luminaire assembly for use in a high ceiling or a ceiling having a shallow plenum depth.
It is still a further object according to the present invention to provide a luminaire assembly having acceptable heat generation and absorption characteristics and which runs at cooler temperatures.
It is still another object according to the present invention to provide an indoor luminaire assembly having acceptable brightness and glare control.
It is yet another object according to the present invention to provide a luminaire assembly which extends below the plane of the ceiling with a vertically oriented lamp without the high angle radiation or visual discomfort which would typically be associated with the same.
It is a further object according to the present invention to provide an indoor luminaire assembly having improved efficiency.
In carrying out these and other objects and goals according to the present invention, a luminaire assembly is provided which is adapted for use indoors mounted in a ceiling. The luminaire assembly includes a reflector portion which has an inner surface formed of a specular material which has relatively high specular reflectance. The assembly also includes an HID lamp which is disposed within the reflector portion for generating light. It further includes an optical unit which is substantially disposed below a plane defined by the ceiling and has a refractor portion with a prismatic structure for distributing the light in a downward direction. In a preferred embodiment, the reflector portion is formed of an anodized aluminum layer which has the relatively high specular material deposited on the inner surface. In a still more preferred embodiment, the specular material is a Miro 4™ material. In another embodiment, the reflector portion is formed of faceted segments attached to each other, and is preferably formed into a segmented hexagonal shape. The inner surface of reflector portion should have an approximately 95% specular reflectance and the total luminaire assembly efficiency should be in the range between 72-79%. Further, the lamp of this luminaire assembly should project below the plane defined by the ceiling.
In another embodiment, provided is an indoor luminaire assembly for installation in a grid ceiling which has a low plenum depth profile and defines a ceiling plane, which includes a frame which is disposed in the grid ceiling and is co-planar with the ceiling plane. Also included is a reflector which is attached to the frame and is disposed substantially above the ceiling plane. The reflector includes a highly specular reflective inner surface which has a relatively high specular reflectance of approximately 95%. A lamp is also included for generating light vertically oriented from the reflector. Further, an optical unit is attached to the frame and has a prismatic refractor which is disposed substantially below the ceiling plane for distributing light therethrough.
In still another embodiment, an indoor recessed luminaire assembly is provided for installation in a drop ceiling which defines a ceiling plane. The indoor luminaire assembly includes a housing which is oriented above the drop ceiling plane and has a lamp socket, a ballast and a capacitor which are mounted therein. Also included is a lamp received in the lamp socket and vertically disposed therefrom for generating light. The lamp is oriented to project below the ceiling plane. Also included is a frame disposed in the drop ceiling and which is co-planar with the ceiling plane. Further included is a reflector disposed above the ceiling plane and attached to the frame, and which has a relatively high specular reflective inner surface. Also included is a glass prismatic optical unit which is attached to the frame and which is disposed below the plane of the drop ceiling for distributing generated light, such that the indoor recessed luminaire assembly has an efficiency in the range of 72-79%.
REFERENCES:
patent: 1846813 (1932-02-01), Pfeiffer
patent: 2630521 (1953-03-01), Kirlin
patent: 6053625 (2000-04-01), Bowker
Minissi Paolo E.
Ries Jack L.
NSI Enterprises Inc.
Quach Y.
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