News Column

Patent Issued for Light Fixture with Co-Formed Plenum Component

July 2, 2014

By a News Reporter-Staff News Editor at Journal of Engineering -- Cree, Inc. (Durham, NC) has been issued patent number 8752976, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventor is Pickard, Paul Kenneth (Morrisville, NC).

This patent was filed on December 28, 2011 and was published online on June 17, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Light emitting diode (LED) lighting systems are becoming more prevalent as replacements for existing lighting systems. LEDs are an example of solid state lighting (SSL) and have advantages over traditional lighting solutions such as incandescent and fluorescent lighting because they use less energy, are more durable, operate longer, can be combined in multi-color arrays that can be controlled to deliver virtually any color light, and generally contain no lead or mercury. In many applications, one or more LED dies (or chips) are mounted within an LED package or on an LED module, which may make up part of a lighting unit, lamp, 'light fixture' or more simply a 'fixture,' which includes one or more power supplies to power the LEDs. An LED fixture may be made with a form factor that allows it to replace a standard fixture or bulb. LEDs can also be used in place of florescent lights as backlights for displays.

"For most LED lamps, LEDs may be selected to provide various light colors to combine to produce light output with a high color rendering index (CRI). The desired color mixing may be achieved, for example, using blue, green, amber, red and/or red-orange LED chips. One or more of the chips may be in a package with a phosphor or may otherwise have a locally applied phosphor. Translucent or transparent materials may be used with LED lighting fixtures to provide diffusion, color mixing, to otherwise direct the light, or to serve as an enclosure to protect the LEDs.

"Rigid or semi-rigid materials may be included in a fixture or lamp as optical elements external to the LED modules themselves. Such optical elements may allow for localized mixing of colors, collimate light, and provide the minimum beam angle possible. Such optical elements may include reflectors, lenses, and/or lens plates. Reflectors can be, for example, of the metallic, mirrored type, in which light reflects of opaque silvered surfaces, or be made of or use white or near-white highly reflective material. Lenses can vary in complexity and level of optical effect, and can be or include traditional lenses, total internal reflection optics, or glass or plastic plates with or without coatings or additives."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventor's summary information for this patent: "Embodiments of the present invention provide troffer-style recessed solid state lighting products using a highly reflective plastic reflectors. In at least some embodiments, a light fixture with a plastic reflector can meet the additional requirements placed on mechanical components exposed to the space above the ceiling plane in plenum return ceiling applications. Thus, a light fixture can be made of lower cost material, and/or be made larger than traditional metal troffers but can still be used in plenum ceiling environments.

"Example embodiments of the present invention include a light fixture with an LED light source and a co-formed reflector to reflect at least some light from the light source. In some embodiments, the co-formed reflector is coextruded from a plenum rated substrate and a reflective material, for example, a plenum rated plastic substrate and a diffuse, white reflective material. In at least some embodiments the light fixture also includes a lens or lens arrangement including at least two lens plates. In at least some embodiments, the light fixture can include a pan disposed on the outside of the reflector to support the fixture, forming an in-ceiling, troffer-style light fixture.

"In some embodiments, the plenum rated substrate for the co-formed reflector includes polyetherimide, a polyphenylene ether/polystyrene blend, polycarbonate, polycarbonate copolymer, or a combination of the foregoing. In some embodiments, a longer fixture can be assembled by using two, complimentary, portions of a co-formed reflector, where these portions are adapted to be joined end-to-end. In some such embodiments, reinforcing members can be used in the co-formed reflector.

"In some embodiments of the invention, the LED light source includes an LED array with at least two groups of LEDs, wherein one group, if illuminated, would emit light having dominant wavelength from 440 to 480 nm, and another group, if illuminated, would emit light having a dominant wavelength from 605 to 630 nm. In some embodiments LEDs in one group are packaged with a phosphor, which, when excited, emits light having a dominant wavelength from 560 to 580 nm.

"In some embodiments one group of LEDs, if illuminated, would emit light having dominant wavelength from 435 to 490 nm, and another group, if illuminated, would emit light having a dominant wavelength from 600 to 640 nm. In some embodiments LEDs in one group are packaged with a phosphor, which, when excited, emits light having a dominant wavelength from 540 to 585 nm.

"A light fixture according to at least some embodiments of the invention can be made by co-forming a plenum rated reflector, fixing a plurality of LED devices to a heatsink to serve as a source of light for the light fixture, and positioning the heatsink with the light source so that at least a portion of the light is reflected from the plenum rated reflector. In some embodiments, the heat sink can be positioned between two lens plates that serve as the lens or lens portion of the reflector and lens assembly of the fixture. A pan may also be attached to the fixture to form an in-ceiling troffer-style fixture."

For the URL and additional information on this patent, see: Pickard, Paul Kenneth. Light Fixture with Co-Formed Plenum Component. U.S. Patent Number 8752976, filed December 28, 2011, and published online on June 17, 2014. Patent URL:

Keywords for this news article include: Cree Inc.

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Source: Journal of Engineering

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