News Column

Patent Issued for Luminaire and Optical Component

June 25, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Vissenberg, Michel Cornelis Josephus Marie (Eindhoven, NL); Krijn, Marcellinus Petrus Carolus Michael (Eindhoven, NL); Uitbeijerse, Bastiaan (Helmond, NL), filed on September 13, 2010, was published online on June 10, 2014.

The patent's assignee for patent number 8746936 is Koninklijke Philips N.V. (Eindhoven, NL).

News editors obtained the following quote from the background information supplied by the inventors: "In many applications, utilizing point sources of light present challenges for developers and providers of products thereof. Examples of point sources are for instance different type of semiconductor light sources such as LEDs and OLEDs.

"Further development of LEDs (Light Emitting Diodes) e.g. higher luminance, have opened new areas for their use. For instance, LEDs may nowadays be utilized in general lighting applications such as luminaires. Thereby the advantages provided by LED technology, such as narrow bandwidth lighting, enhanced control, and low energy consumption, may be utilized in previously unexplored fields of use.

"However, the use of LEDs in general lighting has required quite high demands on the optics used because of e.g. the high brightness provided by the LEDs.

"TIR (Total Internal Reflection) collimators are widely used to shape LED light into a usable beam. They usually consist of an entrance portion, where the LED light is coupled into the light guiding medium, a tapered light guiding part to collimate the beam, and an exit window where the light beam leaves the light guiding medium. The exit window may be smooth, but it can also contain subtle structures to shape the beam further. For example, the beam width may be broadened by applying a frosted surface or a lens array on the exit window as shown in FIGS. 1a-c. FIG. 1a shows optics 15 having circular lenticulars 16 for shaping the light beam at an exit location of a lighting device (not shown). Similarly, FIGS. 1b-c show optics 15 with straight lenticulars 17 across the exit window, and frosted glass 32 respectively."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "It is with respect to the above considerations and others that the present invention has been made.

"In view of the above, it would therefore be desirable to achieve an improved luminaire. In particular, it would be advantageous to achieve a luminaire having improved mixing properties and which reduces beam inhomogeneities.

"To better address one or more of these concerns, in a first aspect of the present invention there is provided an optical component adapted to shape a light beam, the optical component having a refractive surface through which the light beam is allowed to travel, wherein the refractive surface has a plurality of radially extending refractive structures for shaping the light beam.

"Beneficially, light may be refracted mainly in the angular or azimuth direction with respect to the beam due to the radially extending refractive structures. Thereby light in the azimuth direction may be smeared out, and mixing of light in the azimuth direction may be enhanced. This may be in particular be advantageous when shaping light from several light sources of a lighting device (such as a luminaire) distributed around the optical axis of the lighting device. Further, requirements on the internal optics of the lighting device, such as diffusers and mixing cavities may be reduced and/or the aforesaid optical components may be excluded from the lighting device. Thereby, a more cost efficient and simpler lighting device may be provided.

"By comparison, the optics of the prior art as discussed above, is undulating in either the radial direction (for circular lenticulars), or in a perpendicular direction with respect to the direction along which the lenticulars extend (for straight lenticulars). These optics have however essentially no curvature in the azimuth direction, and provide beam broadening and mixing mainly in the radial direction and in horizontal/vertical directions respectively.

"The plurality of radially extending refractive structures may present a periodic undulating pattern in an angular direction of the refractive surface providing a uniform distribution of the refractive structures along the refractive surface in the angular direction. Undulating herein is to be understood as any wavelike shape, such as concave-concave, convex-concave, convex-convex etc. Thereby, light luminance may be smeared out uniformly in the azimuth direction.

"The optical component may have a center and a periphery, and wherein the plurality of radially extending refractive structures extend outwardly from the center towards the periphery.

"Hereto, light may be smeared out in the azimuth direction along any annular section of the optical component.

"Each of the plurality of radially extending refractive structures may have a width that increases linearly in the angular direction as a function of a distance from a center of the optical component.

"Thereby uniform distribution of the refractive structures may be achieved.

"Each of the plurality of radially extending refractive structures may be lenticular. In this context, lenticular is to be construed as being lenticular in the azimuth direction. Further, lenticular may mean e.g. convex, concave, convex-concave and so on. The optical component described hereabove may be included in a luminaire comprising at least one light source adapted to provide a light beam and collimating optics for beam collimation.

"The optical component may present an exit window for a light beam of the luminaire. An exit window in this context is to be construed as the final component along the optical axis in the luminaire, from which light emanates from the luminaire.

"The refractive surface may define a far side of the optical component with respect to the at least one light source. Thus, the refractive surface is positioned on an 'outer' side of the luminaire, whereby the first side is the first side on which light incides.

"Thereby enhanced control of the light beam may be achieved when the light first enters the dense medium via a planar surface, and is refracted when going to air. In contrast, if the light is first refracted by the refractive structures, and then by the planar surface, light rays have a larger probability to have TIR (Total Internal Reflection) at the first side (e.g. the planar surface), and stay inside the material (and hence get scattered uncontrollably).

"The luminaire may comprise a plurality of light sources, each light source being located at least at a distance d from an optical axis O of said luminaire, wherein a radius r of said optical component is at least as large as said distance d. Hence each light source may be refracted efficiently by the optical component.

"The collimating optics may comprise a rotationally symmetric wedge for collimating the light beam, the wedge being arranged between the at least one light source and the optical component. Thereby light may be collimated and distributed over a large area prior to entering the optical component.

"The above aspect and others of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter."

For additional information on this patent, see: Vissenberg, Michel Cornelis Josephus Marie; Krijn, Marcellinus Petrus Carolus Michael; Uitbeijerse, Bastiaan. Luminaire and Optical Component. U.S. Patent Number 8746936, filed September 13, 2010, and published online on June 10, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8746936.PN.&OS=PN/8746936RS=PN/8746936

Keywords for this news article include: Koninklijke Philips N.V.

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Source: Journal of Engineering


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