News Column

Researchers Submit Patent Application, "Led-Based Lighting Unit with a High Flux Density Led Array", for Approval

February 12, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Roberge, Brian (Franklin, MA); Piskun, Nadezhda (Sudbury, MA); Christopher, JR., Gerard Carl (Everett, MA), filed on April 12, 2012, was made available online on January 30, 2014.

The patent's assignee is Koninklijke Philips N.v.

News editors obtained the following quote from the background information supplied by the inventors: "Digital lighting technologies, i.e. illumination based on semiconductor light sources, such as light-emitting diodes (LEDs), offer a viable alternative to traditional fluorescent, HID, and incandescent lamps. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, durability, lower operating costs, and many others. Recent advances in LED technology have provided efficient and robust full-spectrum lighting sources that enable a variety of lighting effects in many applications. Some of the fixtures embodying these sources feature a lighting module, including one or more LEDs capable of producing different colors, e.g. red, green, and blue, as well as a processor for independently controlling the output of the LEDs in order to generate a variety of colors and color-changing lighting effects, for example, as discussed in detail in U.S. Pat. Nos. 6,016,038 and 6,211,626, incorporated herein by reference.

"Entertainment lighting fixtures are known that utilize non-LED light sources, such as incandescent lamps. For example, a popular stage lighting fixture is the SOURCE FOUR, available from Electronic Theatre Controls (ETC) of Middleton, Wis. The SOURCE FOUR utilizes either a HID lamp as a light source or a proprietary halogen HPL lamp. Typical optical system losses from the SOURCE FOUR or similar fixtures may range from, for example, 40-60% from initial lamp lumens. Moreover, the rated lifetime of lamps utilized in such fixtures may only be approximately one thousand hours. Thus, lamps require frequent changeouts to maintain a desired lighting output from the lighting fixture.

"Furthermore, in order to achieve any color effects from the SOURCE FOUR or similar conventional fixture, it is typically necessary to utilize gels. Due to their transmission coefficient, gels considerably cut the light output of an associated fixture. Moreover, gels tend to brown or burn up over time due to the extreme heat caused by the utilized incandescent lamp(s). Thus, the gels reduce light output of a fixture and require frequent change outs to maintain a desired lighting level and/or color from the fixture.

"It has been proposed to utilize an LED light source in lieu of the incandescent light source in entertainment lighting fixtures. The LED light source in such fixtures attempts to replicate the light output of the incandescent source and may be utilized in combination with gels as desired. However, such entertainment lighting fixtures utilizing an LED light source suffer from one or more drawbacks. For example, the LED lighting fixtures may be unable to obtain a desired intensity and/or color from the LED light source. Also, for example, when utilized with gobos or other effects, the LED light source may be unable to produce a desired clean hard edge. Instead, the LED light source often causes unacceptable levels of color fringing or chromatic aberration.

"Thus, there is a need in the art to provide a LED-based lighting unit that provides satisfactory intensity and/or color performance and/or provides a satisfactory hard edge when utilized with gobos or other effects and that may optionally be utilized in entertainment lighting fixtures."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "The present disclosure is directed to inventive methods and apparatus for a LED-based lighting unit having a high flux density LED array that includes a plurality of LEDs of various colors. For example, an LED based lighting unit may include an array of optionally high brightness LEDs of various spectra and the LEDs may be arranged so as to occupy a substantial percentage of the area generally defined by the outermost extent of the array of LEDs. The various color LEDs may optionally be intermixed with certain parameters to provide for desired color mixing from the LEDs. The LED-based lighting unit may optionally include a single reflector provided around the entirety of the array of LEDs. Optionally, the single reflector may be free of diffusers or other light altering lens. The LED-based lighting unit may be implemented in a lighting fixture, such as an entertainment lighting fixture.

"Generally, in one aspect, an LED-based lighting unit is provided that includes a circuit board having a high density array of LED connection pads. Each of the LED connection pads is electrically connected to a single of a plurality of individual channels of the circuit board. The circuit board further includes a plurality of filled vias. At least some of the vias extend between a portion of a single of the LED connection pads and one of a plurality of interior conductive traces each electrically coupled to a single of the individual channels. A plurality of surface mount LEDs are each coupled to a single of the LED connection pads. The LEDs are of at least five different spectra. Each of the LEDs of a single of the spectra is electrically connected to a single of the channels and has a peak wavelength that varies from at least two other of the spectra by at least twenty nanometers. At least seventy percent of an area within which the LEDs are placed is occupied by the LEDs. The area being generally defined by a shape conforming to the outermost extent of the LEDs.

"In some embodiments, at least eighty percent of the area within which the LED are placed is occupied by the LEDs. In some embodiments, the circuit board includes a metal core.

"Also, at least seven different of the spectra may be provided. In some embodiments, the spectra include a first non-white spectrum. A plurality of the LEDs are of the first non-white spectrum and each of the LEDs of the first non-white spectrum is bordered only by the LEDs of a unique of the spectra.

"In other embodiments, a plurality of the LEDs are of a non-white spectrum. A majority of the LEDs of the non-white spectrum are bordered only by the LEDs of a unique of the spectra. In yet other embodiments, a plurality of the LEDs are of a non-white spectrum and each of the LEDs of the non-white spectrum are bordered only by LEDs of a unique of the spectra.

"The LEDs can be arranged in at least one substantially linear row.

"In some embodiments, the lighting unit includes a single reflector surrounding all of the LEDs. In some versions of those embodiments the reflector includes a hollow interior that is diffuser free.

"Generally, in another aspect, an LED-based lighting unit is provided that includes a circuit board having a high density array of LED connection pads. Each of the LED connection pads is electrically connected to a single of a plurality of individual channels of the circuit board. A plurality of surface mount LEDs are included and each is coupled to a single of the LED connection pads. A single reflector surrounds all of the LEDs. The LEDs are of at least five different spectra. Each of the LEDs of a single of the spectra is electrically connected to a single of the channels and has a peak wavelength that varies from at least one other of the spectra by at least twenty nanometers. At least seventy percent of an area within which the LEDs are placed is occupied by the LEDs. The area is generally defined by a shape conforming to the outermost extent of the LEDs.

"In some embodiments, at least eighty percent of the area within which the LEDs are placed is occupied by the LEDs. At least eight different of the spectra may be provided.

"In some embodiments, the reflector is a horn type reflector and optionally includes a hollow interior that is diffuser free.

"In some embodiments, the lighting unit further includes a heat dissipating structure in thermal connectivity with the circuit board. The heat dissipating structure optionally includes a heat slug adjacent the circuit board and a plurality of heat pipes extending from the heat slug into a plurality of cooling fins. In some versions of those embodiments, the lighting unit further includes a support structure supporting the circuit board and in direct contact with at least one of the cooling fins and the heat slug.

"Generally, in another aspect, an entertainment lighting fixture is provided that includes a circuit board having a high density array of LED connection pads. Each of the LED connection pads is electrically connected to a single of a plurality of individual channels of the circuit board. A plurality of surface mount LEDs are included and each is coupled to a single of the LED connection pads. The lighting unit also includes a single reflector that has a base surrounding all of the LEDs and a top distal the base. The top defines a reflector light output opening. A housing surrounds the circuit board, the LEDs, and the single reflector. The housing defines a housing light output opening that is in optical communication with the reflector light output opening. The LEDs are of at least three different spectra. Each of the LEDs of a single of the spectra is electrically connected to a single of the channels and has a peak wavelength that varies from at least one other of the spectra by at least twenty nanometers. The reflector is diffuser free between the base and the reflector light output opening.

"In some embodiments, the entertainment lighting fixture is diffuser free between the reflector light output opening and the housing light output opening.

"As used herein for purposes of the present disclosure, the term 'LED' should be understood to include any electroluminescent diode or other type of carrier injection/junction-based system that is capable of generating radiation in response to an electric signal. Thus, the term LED includes, but is not limited to, various semiconductor-based structures that emit light in response to current, light emitting polymers, organic light emitting diodes (OLEDs), electroluminescent strips, and the like. In particular, the term LED refers to light emitting diodes of all types (including semi-conductor and organic light emitting diodes) that may be configured to generate radiation in one or more of the infrared spectrum, ultraviolet spectrum, and various portions of the visible spectrum (generally including radiation wavelengths from approximately 400 nanometers to approximately 700 nanometers). Some examples of LEDs include, but are not limited to, various types of infrared LEDs, ultraviolet LEDs, red LEDs, blue LEDs, green LEDs, yellow LEDs, amber LEDs, orange LEDs, and white LEDs (discussed further below). It also should be appreciated that LEDs may be configured and/or controlled to generate radiation having various bandwidths (e.g., full widths at half maximum, or FWHM) for a given spectrum (e.g., narrow bandwidth, broad bandwidth), and a variety of dominant wavelengths within a given general color categorization.

"For example, one implementation of an LED configured to generate essentially white light (e.g., a white LED) may include a number of dies which respectively emit different spectra of electroluminescence that, in combination, mix to form essentially white light. In another implementation, a white light LED may be associated with a phosphor material that converts electroluminescence having a first spectrum to a different second spectrum. In one example of this implementation, electroluminescence having a relatively short wavelength and narrow bandwidth spectrum 'pumps' the phosphor material, which in turn radiates longer wavelength radiation having a somewhat broader spectrum.

"It should also be understood that the term LED does not limit the physical and/or electrical package type of an LED. For example, as discussed above, an LED may refer to a single light emitting device having multiple dies that are configured to respectively emit different spectra of radiation (e.g., that may or may not be individually controllable). Also, an LED may be associated with a phosphor that is considered as an integral part of the LED (e.g., some types of white LEDs). In general, the term LED may refer to packaged LEDs, non-packaged LEDs, surface mount LEDs, chip-on-board LEDs, T-package mount LEDs, radial package LEDs, power package LEDs, LEDs including some type of encasement and/or optical element (e.g., a diffusing lens), etc.

"The term 'light source' should be understood to refer to any one or more of a variety of radiation sources, including, but not limited to, LED-based sources (including one or more LEDs as defined above), incandescent sources (e.g., filament lamps, halogen lamps), fluorescent sources, phosphorescent sources, high-intensity discharge sources (e.g., sodium vapor, mercury vapor, and metal halide lamps), lasers, other types of electroluminescent sources, pyro-luminescent sources (e.g., flames), candle-luminescent sources (e.g., gas mantles, carbon arc radiation sources), photo-luminescent sources (e.g., gaseous discharge sources), cathode luminescent sources using electronic satiation, galvano-luminescent sources, crystallo-luminescent sources, kine-luminescent sources, thermo-luminescent sources, triboluminescent sources, sonoluminescent sources, radioluminescent sources, and luminescent polymers.

"A given light source may be configured to generate electromagnetic radiation within the visible spectrum, outside the visible spectrum, or a combination of both. Hence, the terms 'light' and 'radiation' are used interchangeably herein. Additionally, a light source may include as an integral component one or more filters (e.g., color filters), lenses, or other optical components. Also, it should be understood that light sources may be configured for a variety of applications, including, but not limited to, indication, display, and/or illumination. An 'illumination source' is a light source that is particularly configured to generate radiation having a sufficient intensity to effectively illuminate an interior or exterior space. In this context, 'sufficient intensity' refers to sufficient radiant power in the visible spectrum generated in the space or environment (the unit 'lumens' often is employed to represent the total light output from a light source in all directions, in terms of radiant power or 'luminous flux') to provide ambient illumination (i.e., light that may be perceived indirectly and that may be, for example, reflected off of one or more of a variety of intervening surfaces before being perceived in whole or in part).

"The term 'spectrum' should be understood to refer to any one or more frequencies (or wavelengths) of radiation produced by one or more light sources. Accordingly, the term 'spectrum' refers to frequencies (or wavelengths) not only in the visible range, but also frequencies (or wavelengths) in the infrared, ultraviolet, and other areas of the overall electromagnetic spectrum. Also, a given spectrum may have a relatively narrow bandwidth (e.g., a FWHM having essentially few frequency or wavelength components) or a relatively wide bandwidth (several frequency or wavelength components having various relative strengths). It should also be appreciated that a given spectrum may be the result of a mixing of two or more other spectra (e.g., mixing radiation respectively emitted from multiple light sources).

"For purposes of this disclosure, the term 'color' is used interchangeably with the term 'spectrum.' However, the term 'color' generally is used to refer primarily to a property of radiation that is perceivable by an observer (although this usage is not intended to limit the scope of this term). Accordingly, the terms 'different colors' implicitly refer to multiple spectra having different wavelength components and/or bandwidths. It also should be appreciated that the term 'color' may be used in connection with both white and non-white light.

"The term 'color temperature' generally is used herein in connection with white light, although this usage is not intended to limit the scope of this term. Color temperature essentially refers to a particular color content or shade (e.g., reddish, bluish) of white light. The color temperature of a given radiation sample conventionally is characterized according to the temperature in degrees Kelvin (K) of a black body radiator that radiates essentially the same spectrum as the radiation sample in question. Black body radiator color temperatures generally fall within a range of from approximately 700 degrees K (typically considered the first visible to the human eye) to over 10,000 degrees K; white light generally is perceived at color temperatures above 1500-2000 degrees K.

"The term 'lighting fixture' is used herein to refer to an implementation or arrangement of one or more lighting units in a particular form factor, assembly, or package. The term 'lighting unit' is used herein to refer to an apparatus including one or more light sources of same or different types. A given lighting unit may have any one of a variety of mounting arrangements for the light source(s), enclosure/housing arrangements and shapes, and/or electrical and mechanical connection configurations. Additionally, a given lighting unit optionally may be associated with (e.g., include, be coupled to and/or packaged together with) various other components (e.g., control circuitry) relating to the operation of the light source(s). An 'LED-based lighting unit' refers to a lighting unit that includes one or more LED-based light sources as discussed above, alone or in combination with other non LED-based light sources. A 'multi-channel' lighting unit refers to an LED-based or non LED-based lighting unit that includes at least two light sources configured to respectively generate different spectra of radiation, wherein each different source spectrum may be referred to as a 'channel' of the multi-channel lighting unit.

"The term 'controller' is used herein generally to describe various apparatus relating to the operation of one or more light sources. A controller can be implemented in numerous ways (e.g., such as with dedicated hardware) to perform various functions discussed herein. A 'processor' is one example of a controller which employs one or more microprocessors that may be programmed using software (e.g., microcode) to perform various functions discussed herein. A controller may be implemented with or without employing a processor, and also may be implemented as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions. Examples of controller components that may be employed in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).

"It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

"In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

"FIG. 1 illustrates an exploded perspective view of an embodiment of a stage lighting fixture having an LED-based lighting unit with a high flux density LED array; the outer housing of the stage lighting fixture is not illustrated in FIG. 1.

"FIG. 2 illustrates a perspective view of the stage lighting fixture of FIG. 1; a portion of the outer housing of the stage lighting fixture is removed to better show certain components of the stage lighting fixture.

"FIG. 3 illustrates a plan view of the LEDs and circuit board of the embodiment of the LED-based lighting unit of FIG. 1.

"FIG. 4A illustrates a plan view of an internal conduction layer of the circuit board of FIG. 3.

"FIG. 4B illustrates a plan view of a top conduction layer of the circuit board of FIG. 3."

For additional information on this patent application, see: Roberge, Brian; Piskun, Nadezhda; Christopher, JR., Gerard Carl. Led-Based Lighting Unit with a High Flux Density Led Array. Filed April 12, 2012 and posted January 30, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=3497&p=70&f=G&l=50&d=PG01&S1=20140123.PD.&OS=PD/20140123&RS=PD/20140123

Keywords for this news article include: Electronics, Circuit Board, Semiconductor, Microprocessors, Light-emitting Diode, Koninklijke Philips N.v..

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Source: Electronics Newsweekly


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