WO2015140760A1

WO2015140760A1 - Led packages and apparatuses with enhanced color uniformity, and manufacturing method therefor.

Info

Publication number: WO2015140760A1
Application number: PCT/IB2015/052042
Authority: WO
Inventors: Thomas DEFLANDRE; Rémi Noirot; Werner Karl Goetz; Jan-Ivo Blankestijn
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2014-03-20
Filing date: 2015-03-20
Publication date: 2015-09-24
Anticipated expiration: 2016-09-20

Abstract

Color uniformity over a wide range of viewing positions for mid-power packages is achieved by adjusting the configuration (804d) of LEDs within a given LED package (812). In particular, the LEDs (802) within a given package can be configured such that the area (829) occupied by LEDs when the packages are superimposed is substantially larger than the area (831) of the superimposition that is unoccupied by the LEDs to significantly enhance the color uniformity of the system. In addition, the LED dies or chips within a given LED package can also be arranged asymmetrically to improve the color uniformity of the system.

Description

Led Packages And Apparatuses With Enhanced Color Uniformity

Technical Field

[0001] The present invention is directed generally to light-emitting diode (LED) packages and apparatuses and methods of their fabrication. More particularly, various inventive methods and apparatuses disclosed herein relate to improvement of color-over-position properties.

Background

[0002] 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.

[0003] Mid-power LED packages can provide a relatively cost-effective means for fabricating lighting devices for a variety of different applications, including office lighting, down-lighting and road lighting applications, as they are widely available due to their extensive use in backlighting systems. However, one drawback of utilizing mid-power LED packages is that the color of the light emitted by these packages is not consistent across a wide range of viewing angles and positions. In addition, a larger number of mid-power LEDs per package would need to be employed to achieve the same lighting effects of high-power LEDs. Thus, to achieve these effects, such mid-power packages often include two or more LED chips or dies in a given package. Further, if a phosphor converter is employed, the converter in this case would typically encapsulate all of the LEDs in the package to simplify the fabrication process, possibly resulting in undesirable light emission effects. As such, straightforward implementation of mid- power packages in this way would often involve a tradeoff between the size of the luminaire and color consistency over a range of viewing angles.

[0004] One method for addressing color disparities over different viewing angles for LED systems involves rotating LED packages in the system. In particular, individual packages are oriented differently on a circuit board so that the collective effect of the light output by the packages provides a uniform color over a range of viewing angles at a target field.

Summary

[0005] Although orienting packages alone can be effective in reducing color disparities, the correction capability is limited, as the number of variations and combinations of orientations is relatively low. Thus, using this method, it is fairly difficult to find and apply an appropriate orientation combination of the LED packages to achieve color uniformity over a large range of viewing angles and positions. Indeed, in some cases, the method may not be capable of providing color uniformity due to these limitations. Thus, there is a need in the art for an improved means of reducing color disparities over different viewing positions and angles for LED systems.

[0006] The present disclosure is directed to inventive methods and apparatuses for improving color uniformity of light output by LED devices over a wide range of viewing angles and positions. In particular, the present disclosure provides a significantly enhanced method for reducing color disparity over different viewing angles and positions by adjusting the position and orientation of LED chips and/or dies within the LED package itself. In addition to adjusting the orientation of LED packages, in accordance with an aspect of the present invention, the position and orientations of LEDs inside a package can be adapted to provide substantial color uniformity over a large range of viewing angles and viewing positions. Further, the inventors of the present application have discovered that positioning and orienting LEDs within respective LED packages of an LED system in a way that increases the area occupied by LEDs when the packages are superimposed results in improved color uniformity of the system. Although not required to achieve color uniformity effects, oftentimes the positioning and orientation of LEDs in LEDs packages are non-symmetrical to achieve improved color uniformity. For example, in contrast to LED packages in which LEDs are centrally and symmetrically disposed, asymmetric positioning and orientation of LEDs within an LED package provides a significantly larger number of possible variations in how light from the various LEDs of packages can be combined and oriented, thereby substantially enhancing the ability to find and implement the correct arrangement for achieving color uniformity and for fine-tuning color characteristics of the light output by the system.

[0007] Generally, one exemplary aspect of the present invention is directed to a method for manufacturing a light-emitting diode system. In accordance with the method, a configuration of at least one LED in an LED package is determined by assessing the effects of at least one of a position and/or an orientation of the LED(s) in the package on color uniformity over a plurality of viewing positions provided by the LED system. As noted above, assessing the position and/or orientation of one or more LEDs within the package itself substantially facilitates color correction and enables the discovery of a configuration that effectively provides improves color uniformity over various viewing positions. The package is fabricated with the determined configuration in the system and is arranged to enhance the color uniformity over the plurality of viewing positions.

[0008] In one exemplary embodiment, the determination of the LED configuration includes performing an adjustment of at least one of the position and/or the orientation of the LED(s) in the package and determining whether the adjustment provides the enhanced color uniformity over the plurality of viewing positions. Thus, the system can, for example, apply a heuristic method by iterating the adjustment of the position and/or orientation and assessing the effects on color uniformity. As indicated above, by enabling adjustment of the LED position and/or orientation within the package itself, color uniformity correction can be substantially facilitated.

[0009] In accordance with another exemplary embodiment, a first orientation of the LED package in the system can be selected, where the fabrication of the LED system further comprises arranging the package in the system with the selected orientation of the LED package. Thus, in addition to selecting or determining an LED configuration within an LED package, the orientation of the package can be selected or determined to improve the color uniformity. Further, in one particular version of this embodiment, multiple packages can be considered. For example, a different orientation of a different package within the system can also be selected. Thus, in this case, the orientations of the multiple packages can be adjusted such that one or more of the packages have orientations that are different from other packages to enhance the color uniformity of the system. Optionally, the multiple LED packages can have the same configuration of LEDs within the package. Here, fabrication of the LED system is facilitated, as only one type of LED package can be manufactured and used to form the LED system. In accordance with one preferred version of the embodiment, the position and/or the orientation of one or more LEDs in one package is chosen such that superimposition of the package with at least one other package LED package results in a ratio of an area occupied by any of the LEDs in the superimposition to an area unoccupied by any of the LEDs in the superimposition that is at least 0.50. Most preferably, this ratio should be at least 0.80 to achieve a substantial enhancement of color uniformity. In accordance with one exemplary feature, the inventors of the present application have found that these ratio ranges can be utilized as an indicator that the color uniformity will be achieved by the configuration. In other words, to determine the LED configuration within an LED package, the ratio can be calculated and, if the ratio falls within the desired range, it can be assumed that sufficient color uniformity will likely be attained by the package.

[0010] In another exemplary embodiment, the package includes a plurality of LEDs. Here, the determination of the LED configuration is made by selecting the position and/or the orientation of each LED of the plurality of LEDs in the package such that the configuration of the plurality of LEDs is asymmetric with respect to any axis that is parallel to primary light-emitting surfaces of the plurality of LEDs in the system. Similar to the ratio described above, the asymmetric feature can also be used as an indicator that the color uniformity will be achieved by the configuration. One advantage of employing the asymmetric feature is that the determination of the appropriate configuration is substantially simpler. Thus, less complex circuitry and/or software can be utilized to find an appropriate configuration, thereby providing a cost-effective means for finding a suitable LED configuration. However, the use of the ratio feature discussed above is more accurate and, as such, is more preferable than the use of the asymmetric feature.

[0011] Another aspect is directed to a computer readable medium. The computer readable medium includes a computer readable program for designing an LED system. The computer readable program, when executed on a computer, causes the computer to perform the step of determining a configuration of at least one LED in an LED package by assessing effects of at least one of a position and/or an orientation of the LED(s) in the package on color uniformity over a plurality of viewing positions provided by the LED system. In accordance with one exemplary embodiment, the computer readable medium is a computer readable storage medium. Alternatively, in accordance with another exemplary embodiment, the computer readable medium is a computer readable signal medium.

[0012] One other exemplary aspect of the present invention is directed to an LED package. Here, the package includes at least one LED, where each LED includes a respective cathode, anode and electroluminescent material between the cathode and the anode. Further, the LED(s) is positioned and oriented in a particular configuration that enables a superimposition of the LED package with at least one other LED package having the same configuration such that a ratio of an area occupied by any of the LEDs in the superimposition to an area unoccupied by any of the LEDs in the superimposition is at least 0.5 to enhance a color uniformity over a plurality of viewing positions. In accordance with a preferred embodiment, this

superimposition ratio is at least 0.80. As noted above, configuring the package so that the superimposition ratio falls within these ranges results in a package that has a substantial color uniformity over various viewing positions.

[0013] In another embodiment, the LED package includes a phosphor component that encapsulates the LEDs, where the color uniformity is provided for light output from the phosphor component. In one version of the embodiment, the phosphor component encapsulates a plurality of LEDs. The LED configurations described herein are especially suitable to LED packages that employ phosphor converters, as they are particularly susceptible to color over position and color over angle variations. [0014] Another exemplary aspect of the present invention is directed to an LED apparatus including a plurality of LED packages that are configured such that superimposition of the LED packages results in a ratio of an area occupied by any of the LEDs in a superimposition of the packages to an area unoccupied by any of the LEDs in the superimposition that is at least 0.5 to provide the color uniformity over a plurality of viewing positions. In one embodiment, at least two of the LED packages have the same configuration but are oriented differently in the apparatus. As indicated above, manufacturing at least a subset of the packages so that they have the same configuration simplifies the fabrication process, while still permitting a significant correction in color uniformity over different viewing positions.

[0015] Alternatively, in accordance with a different embodiment, at least one of the packages has an LED configuration that is different from the LED configuration of another LED package. By using packages with different configurations, the color uniformity over various viewing positions of the apparatus can be more easily fine-tuned.

[0016] In another embodiment, the apparatus includes a system of lenses, where each lens of the system is disposed over a different one of the plurality of LED packages. Here, the color uniformity is provided for light output from the system of lenses. Apparatuses that employ lenses also tend to be susceptible to color non-uniformity over various viewing angles or positions, as the adjustment of the path of the light rays from the packages through the lenses can exacerbate the color non-uniformity problem. Thus, the LED configurations of the packages are particularly suitable to such LED apparatuses.

[0017] An alternative exemplary aspect of the present invention is directed to an LED package including a plurality of LEDs, where each of the LEDs includes a respective cathode, anode and electroluminescent material between the cathode and the anode. Further, the LEDs are positioned and oriented in a particular configuration of the LEDs that is asymmetric with respect to any axis that is parallel to primary light-emitting surfaces of the plurality of LEDs in the package to provide an enhanced color uniformity over a plurality of viewing positions. As noted above, asymmetric positioning and orientation of LEDs within an LED package provides a relatively large number of possible variations in the manner in which light from the various LEDs of packages can be combined and oriented. As a result, the ability to find and implement a suitable arrangement for achieving color uniformity and for fine-tuning color characteristics of the light output by the system is substantially enhanced. In one particular embodiment, the package includes a phosphor component that encapsulates the plurality of LEDs, where the color uniformity is provided for light output from the phosphor component. As discussed above, mid-power packages that utilize a phosphor converter are particularly prone to a lack of color uniformity over different viewing positions. The LED configuration is especially suited for these types of packages.

[0018] Another aspect of the present invention is directed to an LED apparatus including a plurality of LED packages, where each of the packages has a respective plurality of LEDs that are positioned and oriented in a respective configuration that is asymmetric with respect to any axis that is parallel to primary light-emitting surfaces of the LEDs in the packages to provide the color uniformity over the plurality of viewing positions. In one particular embodiment, at least two of the packages have different configurations to, for example, better enable fine-tuning of the color properties of the light output by the LED apparatus. In another embodiment, at least two of the packages have the same LED configuration but are oriented differently. As noted above, use of packages with the same LED configuration facilitates cost-effective manufacturing of the apparatus. In another exemplary embodiment, the apparatus includes a system of lenses, where each lens of the system is disposed over a different one of the plurality of LED packages and where the LED configurations provide a color uniformity for light output from the system of lenses.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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). [0023] 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).

[0024] 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).

[0025] 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. [0026] 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 spectrums of radiation, wherein each different source spectrum may be referred to as a "channel" of the multi-channel lighting unit.

[0027] 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).

[0028] In various implementations, a processor or controller may be associated with one or more storage media (generically referred to herein as "memory," e.g., volatile and non-volatile computer memory such as RAM, PROM, EPROM, and EEPROM, floppy disks, compact disks, optical disks, magnetic tape, etc.). In some implementations, the storage media may be encoded with one or more programs that, when executed on one or more processors and/or controllers, perform at least some of the functions discussed herein. Various storage media may be fixed within a processor or controller or may be transportable, such that the one or more programs stored thereon can be loaded into a processor or controller so as to implement various aspects of the present invention discussed herein. The terms "program" or "computer program" are used herein in a generic sense to refer to any type of computer code (e.g., software or microcode) that can be employed to program one or more processors or controllers.

[0029] The term "network" as used herein refers to any interconnection of two or more devices (including controllers or processors) that facilitates the transport of information (e.g. for device control, data storage, data exchange, etc.) between any two or more devices and/or among multiple devices coupled to the network. As should be readily appreciated, various implementations of networks suitable for interconnecting multiple devices may include any of a variety of network topologies and employ any of a variety of communication protocols.

Additionally, in various networks according to the present disclosure, any one connection between two devices may represent a dedicated connection between the two systems, or alternatively a non-dedicated connection. In addition to carrying information intended for the two devices, such a non-dedicated connection may carry information not necessarily intended for either of the two devices (e.g., an open network connection). Furthermore, it should be readily appreciated that various networks of devices as discussed herein may employ one or more wireless, wire/cable, and/or fiber optic links to facilitate information transport throughout the network.

[0030] 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

[0031] 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.

[0032] FIG. 1 illustrates a block diagram of an exemplary LED device.

[0033] FIG. 2 illustrates a block diagram of an exemplary LED package.

[0034] FIG. 3 illustrates a diagram of an exemplary LED system.

[0035] FIG. 4 illustrates a diagram of an exemplary LED apparatus in accordance with an exemplary embodiment of the present invention.

[0036] FIG. 5 illustrates a high-level flow diagram of a method for manufacturing an LED system and apparatus in accordance with an exemplary embodiment of the present invention.

[0037] FIG. 6 illustrates a diagram depicting color disparity over different viewing angles of an exemplary mid-power LED package.

[0038] FIG. 7 illustrates diagrams of LED packages in accordance with various exemplary embodiments of the present invention.

[0039] FIG. 8 illustrates diagrams of LED packages and their superimposition characteristics in accordance with various exemplary embodiments of the present invention.

[0040] FIG. 9 illustrates a block/flow diagram of an exemplary computer system that can be configured to implement features of methods for manufacturing a light-emitting diode system and apparatus in accordance with exemplary embodiments of the present invention. Detailed Description

[0041] As discussed above, one problem with employing mid-power LED packages for a variety of applications is that the color of the light emitted by these packages is not uniform over a wide range of viewing angles and positions. To address the problem, more generally, Applicants have recognized and appreciated that it would be beneficial to adjust the position and orientation of LED chips or dies within the package itself to ensure that the color is consistent across a large range of viewing positions and angles. In particular, the adjustment can be made to increase the area occupied by LED dies or chips when the packages are superimposed. The inventors have found that adjusting the LED packages in this way provides a substantial improvement in color uniformity in the system. Alternatively or additionally, the adjustment can be made to position the LED chips or dies in the package so that they are asymmetrical, which in turn enhances the ability to find and implement an effective

arrangement for achieving color uniformity and for fine-tuning color characteristics of the light emitted by the system. Each of these aspects provide an effective means for reducing color disparity over different viewing angles and positions.

[0042] Referring to FIG. 1, an exemplary LED device 100 is illustratively depicted in a cross- section of a side view. The LED device 100 includes an LED 107, which can be implemented as a die or a chip, and a phosphor component 110. The LED 107 includes a cathode 102, an electroluminescent layer 104 and an anode 106. In certain implementations, layer 102 can be the anode and layer 106 can be the cathode. As indicated above, the anode 106 can be composed of ITO, for example, while the cathode 102 can be composed of a metal, such as aluminum, for example. The LED can be an InGaN LED or it can be an organic light-emitting diode, where the electroluminescent layer is formed of an organic material. In addition, a phosphor converter or component 110 can be placed over the LED 107 to ideally convert, for example, blue light 108 into white light 112. FIG. 2 illustrates an exemplary package 200 in a cross-section of a side view. The package 200 comprises a housing 202 including an LED 204, which can be the LED 107 of FIG. 1, and a phosphor material or converter 206, which encapsulates the LED 204. Further, electrical connectors 208 can be coupled to the LED 204 to provide power to the LED 204. Here, the LED 204, and also the LED 107, can be a blue-emitting LED. Thus, blue light 210 interacts with a phosphor particle 212 of the phosphor material or component 206, which in turn re-emits yellow light 214. In addition, some of the blue light 216 is emitted directly out of the phosphor component 206 without interacting with a phosphor particle. The mixing of yellow light 214 and blue light 216 results in white light.

[0043] FIG. 3 illustrates a top view an exemplary light-emitting apparatus 300 during an intermediate processing stage, where phosphor material has not yet been deposited in elements 201 of the housing 202. Here, the housing 202 can include several packages 200, which are formed by depositing phosphor material 206/110 over the LED 204. As illustrated in elements 201 of FIG. 3, the LED dies/chips 204 are disposed in the package in a relatively central and symmetric configuration. FIG. 4, in turn, illustrates another exemplary light- emitting apparatus 400, which comprises a housing or board 402 including LED packages 406. In addition, a system of lenses 404 can be placed above the LED packages 406 such that each lens of the system is disposed over a different one of the LED packages 406.

[0044] As noted above, a variance in color over angle that is visible on a far field is a significant problem in lighting systems that employ mid-power packages. The problem is linked to the architecture of the package itself. In particular, the light-emitting area of a mid-power package is substantially different from the light-emitting area of a high-power package.

Specifically, there is a considerable contrast in color in the near field over the chip/die area and phosphor area of such packages, which in turn induces discrepancies in color over position on the surface of the chip/die. This variation in color over position forms a variation in color over angle in the far field when an optical element is disposed over the package. For example, FIG. 6 provides a diagram 600 illustrating the color over angle problem. Here, portion 601 of the diagram is a representation of light as it appears in an area in a far field. Element 602 denotes an area 2 that is near the center of the light distribution in the far field area, while element 604 denotes an area 1 that is at larger viewing angle from the center of the light distribution in the far field area. As illustrated in portion 605 of the diagram 600, light 606 in area 1 604 has a substantially bluish hue, while light 608 in area 2 602 is substantially white. Thus, the variance in color over angle is a significant problem in lighting systems that utilize mid-power packages. The methods, systems, apparatuses and devices herein address each of these problems. [0045] In view of the foregoing, various embodiments and implementations of the present invention are directed to methods, systems, apparatuses and devices for enhancing color uniformity over a wide range of viewing positions and viewing angles. It should be noted that each of the LEDs discussed herein below can be LED 107 of FIG. 1 and can be an LED chip or an LED die. With reference now to FIG. 5, an exemplary method 500 for manufacturing an LED system is illustratively depicted. The method 500 can begin at step 502 at which LED configuration(s) in one or more LED packages is determined. In particular, the determination of the LED configuration(s) can be made by assessing the effects of at least one of a position and/or an orientation of the LED(s) in the package on color uniformity over a plu rality of viewing positions provided by the LED system. For example, at step 504, one or more initial LED configurations for one or more corresponding LED packages can be selected. Examples of LED configurations that can be selected include configuration 704 of FIG. 7 and configurations 804a, 804b, 804c, 804d and 804e illustrated in FIG. 8. It should be understood that the number of LEDs in a given package need not be limited to two LEDs. For example, the number of LEDs can be any number of LEDs that are feasible for a given package size, include three LEDs, four LEDs, five LEDs, etc. In addition, as discussed herein below, even one LED in a given package can provide a relatively suitable color uniformity.

[0046] In the method 500, at block 508, a minimum superimposition ratio of occupied versus unoccupied LED areas can be applied. The selection at step 504 can implement block 508, where the block is preconfigured to select an LED configuration for any given package by selecting the position and/or the orientation of the LED(s) in a given LED package such that superimposition of the given LED package with another package with the same LED

configuration results in a ratio of an area occupied by any of the LEDs in the superimposition to an area unoccupied by any of the LEDs in the superimposition that is at least 0.5, most preferably at least 0.80 to achieve a substantial enhancement of color uniformity. For example, FIG. 8 illustrates top views of LED packages 806, 808, 810, 812 and 814, which respectively have LED configurations 804a, 804b, 804c, 804d and 804e. In addition, FIG. 8 further illustrates top views of superimpositions 805, 809, 811, 813 and 815 corresponding to LED configurations 804a, 804b, 804c, 804d and 804e, respectively. Set 820 includes superimposition 805 and denotes a superimposition of two packages 806 each having LED configuration 804a, while set 850 includes superimpositions 809, 811, 813 and 815 and denotes a superimposition of four packages. For example, superimposition 809 denotes a superimposition for four packages 808, each package 808 having the LED configuration 804b, superimposition 811 denotes a superimposition for four packages 810, each package 810 having the LED configuration 804c, superimposition 813 denotes a superimposition for four packages 812, each package 812 having the LED configuration 804d and superimposition 815 denotes a superimposition for four packages 814, each package 814 having the LED configuration 804e. However, it should be noted that the number of packages considered in the superimposition need not be limited to two or four, but can include other numbers of superimpositions, including three or five, for example.

[0047] As illustrated by the superimposition 813 of FIG. 8, the area 829 occupied by any of the LEDs in the superimposition is substantially greater than an area 831 that is unoccupied by any of the LEDs in the superimposition. In particular, the ratio of area 829 to area 831 is greater than 0.80. Similarly, in the superimposition 809 of FIG. 8, the area 821 occupied by any of the LEDs in the superimposition is substantially greater than an area 823 that is unoccupied by any of the LEDs in the superimposition. Here, the ratio of area 821 to area 823 is the next greatest ratio in any of the superimpositions of sets 820 and 850 after the ratio of area 829 to area 831. As also illustrated in FIG. 8, the ratios of the LED occupied areas 825, 833 in superimpositions 811, 815, respectively, to unoccupied areas 827, 835 of superimpositions 811, 815, respectively, is also significantly large and substantially greater than 0.50. However, ratios of 0.50 can, in certain cases, be sufficient to provide a desired color uniformity. In contrast to the

configurations 804b-804e, the configuration 804a provides a superimposition ratio that is relatively small. For example, as illustrated in superimposition 805, the ratio of the area 807 occupied by any of the LEDs in the superimposition 805 to the area 803 that is unoccupied by any of the LEDs in the superimposition is rather small. Notice that, even if a larger number of packages with the configuration 804a were superimposed, the central area in the

superimposition would be largely unoccupied. Thus, the LED configuration, namely the position and/or orientation of the LED(s), in a given package is a significant factor in attaining the desired ratio.

[0048] As indicated above, a superimposition ratio of at least 0.50, most preferably at least 0.80, provides a substantial enhancement of color uniformity over a wide range of viewing positions provided by the LED system. For example, the range of viewing positions can correspond to, for example, viewing positions along the entire top surface of the package (illustrated for example in the top views of the packages in FIG. 8), or 85° in any direction from the normal line of at the center of the top surface of the LED package. For example, the viewing positions can be measured from the top view of the package(s) illustrated in FIG. 8 or FIG. 3. Similarly, the viewing position can be measured from the top of the packages 406 in the illustration depicted in FIG. 4 or the top of the lenses 404 illustrated in FIG. 4.

[0049] The superimposition ratio of at least 0.50, most preferably at least 0.80, results in a system of packages that essentially offset the color effects of each other to provide, for example, white light, over the wide range of viewing positions. For example, in one exemplary implementation, all or most of the packages in the system can have the same LED configuration but different orientations with respect to each other. For example, as illustrated in FIG. 7, the packages of sets 710, 720 and 730 can have the configuration 704. In set 720, two packages 700a and 700b can be employed with orientations that are offset from each other by 90°. Similarly, two packages 806 of LEDs 802 with orientations offset by 180°, as illustrated in the superimposition 805, can be employed. Here, in either case, the two packages can correspond to any two adjacent packages, such as adjacent packages 200 in any row or column in system 300 of FIG. 3, except of course that the LED configuration 704 is employed, or adjacent packages 406 on board or system 402 of FIG. 4. For example, the set of two adjacent packages can correspond to adjacent packages 215, which in turn can be repeated to occupy each package area of the system 300. The set of two adjacent packages 720 or 820 can be repeated regularly in the system, such as for example system 300 or 402, with the LED configuration 704 or 804a employed by the system. The effects of the packages in set 720 offset each other to provide an improved color uniformity over a plurality of viewing positions. In other words, the combined effects of the light emitted from the packages in the set provide an enhanced uniformity over the range of viewing positions.

[0050] Alternatively, sets of four adjacent packages can be employed to provide an even greater enhancement of color uniformity over a wide range of viewing positions. For example, as illustrated in FIG. 7, the package set 730 of adjacent packages having configuration 704 can be used, where the packages 700c, 700d, 700e and 700f in the set 730 have orientations that differ in multiples of 90° from each other, as illustrated in FIG. 7. Similarly, four adjacent packages 812 with configuration 804d can be employed, where the adjacent packages are oriented such that they are also offset from each other by multiples of 90°, as illustrated by superimposition 813. Further, any of the packages of FIG. 8 can be employed, where a set four adjacent packages having the same configuration, such as configuration 804b, 804c, 804e, can be employed and where the packages are oriented differently so that they are offset from each other by 90°, as illustrated by superimpositions 809, 810 and 814. Here, any of the sets of four packages described above can correspond to any four adjacent packages, such as adjacent packages 200 in any row or column in system 300 of FIG. 3, except of course that the respective LED configurations having the superimposition ratio of 0.5, or preferably 0.80, are employed. Similarly, any of the set of four packages can be implemented in adjacent packages 406 on board or system 402 of FIG. 4. For example, the set of four adjacent packages can correspond to adjacent packages 217, which in turn can be repeated to occupy each package area of the system 300. The set of four adjacent packages can be repeated regularly in the system, such as for example system 300 or 402, with the LED configurations of, for example, 704, 804b, 804c, 804d and 804e employed by the system. As discussed above, the combined effects of the light emitted by packages in the set provide an even more enhanced color uniformity over the range of viewing positions.

[0051] It should be noted, for any of the embodiments or versions of embodiments disclosed here, that the repeated set of packages need not be limited to two or four packages, but can consist of other numbers of packages, including three packages, five packages, etc. In addition, the difference in orientations between packages in the sets need not be limited to multiples of 90°, but can be any orientation offset that would achieve a desired color uniformity over a variety of viewing positions. Further, the LED configurations in a repeated set need not be the same. For example, a repeated set of four LED packages may, in certain embodiments, include LED packages that respectively have configurations 804b, 804c, 804d and 804e.

However, other configurations can be used. In addition, the set of LED packages need not be repeated, where one or more of the sets of LED packages in any given LED system, such as systems 300, 400 and 402, can employ unique configurations in the set of LED packages, as long as the sets of packages achieve a desired color uniformity.

[0052] Alternatively or additionally, asymmetric configurations can be applied at block 510. For example, the selection at step 504 can implement block 510 by selecting LED configurations based on asymmetry of the LEDs in the package. For example, as noted above, of the LED configurations illustrated in FIG. 8, LED configurations 812 and 808 provide the most enhanced color uniformity. In particular, the configuration of the LEDs 802 in configurations 812 and 808 is asymmetric with respect to any axis that is parallel to primary light-emitting surfaces of the LEDs in the system. For example, the tops of the LEDs 802, which are illustrated in FIG. 8, are the primary light-emitting surfaces of these LEDs. Here, no axis that is parallel to the primary light-emitting surfaces in configurations 812 and 808 can be drawn that would result in a symmetrical arrangement of LEDs 802. As noted above, the asymmetric positioning and orientation of LEDs within an LED package provides a significantly larger number of possible variations in how light from the various LEDs of packages can be combined and oriented, which in turn substantially enhances the capability of the configuration to achieve an effective color uniformity over a plurality of viewing positions.

[0053] It should be noted that block 508 can also apply a configuration that has only one LED in each package of a given set of adjacent packages, which can, for example, occupy any number of adjacent packages in systems 300, 400 or 402, as discussed above. For example, four or more LED packages can include a configuration in which an LED 802 is disposed at the edge of the package. For example, the configuration can consist of an LED in a position and orientation illustrated by the LED denoted by the lead line to reference character 802 in package 806 in FIG. 8. Here, a sufficient number packages can be employed, with an appropriate size of the LED package, to effect a ring of LEDs in the superimposition to achieve a superimposition ratio of at least 0.5.

[0054] Alternatively, the selection at step 504 can be made randomly or can be selected from a predetermined set of configurations, where a heuristic method is employed and adjustments of the LED configuration in the package(s) can be made iteratively, as discussed herein below.

[0055] Optionally, at step 506, initial orientations of the LED packages can be selected. For example, selection of orientations illustrated in elements 720 or 730 of FIG. 7 or illustrated superimpositions 805, 809, 811, 813 and 815 in FIG. 8 for corresponding sets of packages can be made. Further other orientations for various LED configurations can be made. Alternatively, the selection at step 506 can be incorporated into step 504, where the orientations of the packages are incorporated into the selection of LED configurations of individual packages of any given set of packages.

[0056] At step 511, the LED package configuration and/or the LED package orientations are assessed. For example, a simulation can be conducted with the packages. Here, in the simulation, the packages can be arranged in a simulated system, which can be modeled on, for example, systems 300, 400 or 402, and an assessment of the color uniformity over different viewing positions, such as, for example, the viewing positions defined above, can be made. For example, at step 512, a determination of whether a desired color uniformity has been achieved can be made. If the color varies below a pre-determined threshold variation over the various viewing positions, then the desired color uniformity can be deemed achieved and the method can proceed to step 520. However, if the color varies above the pre-determined threshold variation over the various viewing positions, then it can be deemed that the desired color uniformity is not achieved and the method can proceed to step 514. Here, at step 514, and/or step 516, the method can implement either one or both of the blocks 508 and 510, as discussed above, to adjust the LED configuration, in particular the position and/or orientation, of LED(s) within one or more LED packages. For example, the adjustment of the LED configuration at step 514 can be made in a way that increases the superimposition ratio described above. Alternatively or additionally, the adjustment of the LED configuration at step 514 can be made in a way that increases the asymmetric nature of the configuration or makes the configuration asymmetric as discussed above. Of course, any of the configurations 704, 804a, 804b, 804c, 804d and/or 804e can be used in the adjustment step 514, to, for example, either adjust the configuration to or from these particular configurations. Thereafter, the method can proceed to step 516. Similarly, at optional step 516, the adjustment of the LED package orientation(s) can be made in a way that increases the superimposition ratio described above. Of course, any of the orientations described above, including, the orientations depicted in sets 720 and/or 730 and/or the orientations depicted in the superimpositions 805, 809, 811, 813 and 815 can be used in the adjustment step 516, to, for example, either adjust the orientation(s) to or from these particular orientations. Thereafter, the method can proceed to step 511.

[0057] It should be noted that, at steps 511 and/or step 512, the determination of whether a desired color uniformity is achieved can be made by assessing whether superimposition of a number of LED packages, such as, for example, packages in the sets 720 and/or 730 and/or the sets of LED packages depicted in the superimpositions 805, 809, 811, 813 and 815, results in a superimposition ratio of 0.5, more preferably results in a ratio 0.80. Here, in this example, as opposed to using a simulation to determine whether a color uniformity has been achieved, the superimposition ratio threshold of 0.5, more preferably 0.80, can be used. For example, at step 512, if the superimposition ratio is at or greater than 0.5, more preferably at or greater than 0.80, then the desired color uniformity can be deemed achieved and the method can proceed to step 520. However, if the superimposition ratio is less than 0.5, more preferably less than 0.80, then it can be deemed that the desired color uniformity is not achieved and the method can proceed to step 514. Using this standard for color uniformity simplifies the determination of LED configurations at step 502. Similarly, the symmetry properties of the LED configurations can additionally or alternatively be employed to even further simplify the determination at step 502; however, the assessment using the symmetry properties alone would be less accurate than the use of the superimposition ratio. Here, if the configuration of LEDs in a given LED package is asymmetric with respect to any axis that is parallel to primary light-emitting surfaces of the LEDs in the given package, then the desired color uniformity can be deemed achieved and the method can proceed to step 520. However, if the configuration of LEDs in a given LED package is not asymmetric with respect to any axis that is parallel to primary light-emitting surfaces of the LEDs in the given package, then it can be deemed that the desired color uniformity is not achieved and the method can proceed to step 514.

[0058] At step 520, LED packages that are determined to have adequate color uniformity at step 512 can be fabricated. For example, at step 522, for each LED package, one or more LED chips or dies can be arranged with configuration(s) determined at step 502 and can be deposited on a housing or board, such as, for example, housing 202 or board 402. Here, the LED packages 200 or 406 can be oriented In the same way as the set of orientations, such as, for example, the orientations In the sets 720 and/or 730 of LED packages and/or the sets of LED packages depicted in the superimpositions 809, 811, 813 and 815, determined at step 511 to have a sufficient color uniformity over a plurality of viewing positions. Further, as noted above, orientations of a set of two or four, or other number of packages, can be repeated in any column or row of, for example, housing 202 or board 402. In particular, the combined effect of the differently oriented packages in a given set of packages can significantly enhance the color uniformity over a wide range of viewing positions, as discussed above. At step 524, the LED packages, such as, for example, packages 200 and 406, can be coupled to connectors 208 and each of the packages can be completed by encapsulating the LEDs. For example, as noted above, the LEDs can be encapsulated with a phosphor material, such as, for example, the phosphor converter material 206 or 110 described above. Alternatively, the package can be completed first and then arranged in a housing or on a board. For example, at step 526, for each LED package, one or more LEDs can be encapsulated with, for example, the phosphor converter material 206. Then, at step 528, for each package, such as packages 406, for example, the encapsulated LEDs can be arranged on a board, such as board 402, and can be coupled, through the bottom of the LEDs, to electrical connectors at the top of the board. Here, the encapsulated LEDs packages can be oriented In the same way as the set of orientations, such as, for example, the orientations In the sets 720 and/or 730 of LED packages and/or the sets of LED packages depicted in the superimpositions 809, 811, 813 and 815, determined at step 511 to have a sufficient color uniformity over a plurality of viewing positions. In addition, the orientations of a set of packages can be repeated in any column or row of, for example, housing 202 or board 402, as discussed above. It should be noted that, in each of steps 524 or 526, the LEDs need not be encapsulated with the phosphor material 206 or 106. Alternatively, a layer, such as layer 106, can be deposited on top of each of the LEDs, as illustrated in FIG. 1.

[0059] At step 530, optionally, a lens system can be formed above the packages. For example, the system of lenses 404 illustrated in FIG. 4 can be arranged over the packages 406 such that each lens of the lens system is disposed over a different LED package 406 on the board. Here, the color uniformity over a wide range of viewing positions is provided for light output from the system of lenses. The apparatuses and systems formed in accordance with the method 500 can employ the same form factor as conventional mid-power LEDs, such as 30*30; 35*35. Use of these standard sizes is especially cost-efficient, as they are used extensively in backlighting display applications.

[0060] Referring now to FIG. 9, an exemplary computing system 900 by which method embodiments of the present principles described above can be implemented, is illustrated. The computing system 900 includes a hardware processor or controller 908 that can access random access memory 902 and read only memory 904 through a central processing unit bus 906. In addition, the processor 908 can also access a computer-readable storage medium 920 through an input/output controller 910, an input/output bus 912 and a storage interface 918, as illustrated in FIG. 9. The system 900 can also include an input/output interface 914, which can be coupled to a display device, keyboard, mouse, touch screen, external drives or storage mediums, etc., for the input and output of data to and from the system 900. In accordance with one exemplary embodiment, the processor 908 can access software instructions stored in the storage medium 920 and can access memories 902 and 904 to run the software instructions stored on the storage medium 920 and thereby implement the determination step 502 of the method 500. Alternatively, the software instructions that implement step 502 of the method 500 can be encoded in a computer-readable signal medium, such as a radio frequency signal, an electrical signal or an optical signal. [0061] While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[0062] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

[0063] The indefinite articles "a" and "an," as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean "at least one."

[0064] As used herein in the specification and in the claims, the phrase "at least one," in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B," or, equivalently "at least one of A and/or B") can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0065] It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

[0066] Also, reference numerals appearing between parentheses in the claims, if any, are provided merely for convenience and should not be construed as limiting the claims, in any way.

[0067] In the claims, as well as in the specification above, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMS:

1. A method (500) for manufacturing a light-emitting diode (LED) system comprising: determining (502) a configuration of at least one LED in an LED package by assessing effects of at least one of a position and/or an orientation of the at least one LED in said package on color uniformity over a plurality of viewing positions provided by the LED system; and

fabricating (520) said package with said configuration in said system such that said package is arranged to enhance the color uniformity over the plurality of viewing positions.

2. The method of claim 1, wherein the determining comprises performing an adjustment (514) of at least one of the position and/or the orientation of the at least one LED in said package and determining (512) whether the adjustment provides the enhanced color uniformity over the plurality of viewing positions.

3. The method of claim 1, further comprising:

selecting (506) a first orientation of said LED package in said system, wherein the fabricating further comprises arranging said package in said system with the selected orientation of the LED package.

4. The method of claim 3, wherein the at least one LED is at least one first LED, where the LED package is a first LED package, and wherein the determining further comprises selecting (506) at least one different orientation in said system of at least one other LED package including at least one other LED such that the color uniformity over the plurality of viewing positions is enhanced by the LED system.

5. The method of claim 4, wherein the at least one other package has said determined configuration.

6. The method of claim 5, wherein said determining further comprises selecting (514) the position and/or the orientation of the at least one first LED in said first package such that superimposition of said first LED package with said at least one other package LED package results in a ratio of an area occupied by any of the LEDs in the superimposition to an area unoccupied by any of the LEDs in the superimposition that is at least 0.5.

7. The method of claim 1, wherein said at least one LED in said package is a plurality of LEDs and wherein the determining further comprises selecting the position and/or the orientation of each LED of said plurality of LEDs in said package such that the configuration of the plurality of LEDs is asymmetric with respect to any axis that is parallel to primary light- emitting surfaces of said plurality of LEDs in said system.

8. A computer readable medium (920) comprising a computer readable program for designing a light-emitting diode (LED) system, wherein the computer readable program when executed on a computer causes the computer to perform the step of:

determining a configuration of at least one LED in an LED package by assessing effects of at least one of a position and/or an orientation of the at least one LED in said package on color uniformity over a plurality of viewing positions is provided by the LED system.

9. The computer readable medium of claim 7, wherein the medium is a computer readable storage medium.

10. The computer readable medium of claim 7, wherein the medium is a computer readable signal medium.

11. A light-emitting diode (LED) package (812) comprising:

at least one LED (107), each LED including a respective cathode, anode and

electroluminescent material between the cathode and the anode, wherein the at least one LED is positioned and oriented in a particular configuration (804d) that enables a superimposition of said LED package with at least one other LED package having said configuration such that a ratio of an area occupied by any of the LEDs in the superimposition to an area unoccupied by any of the LEDs in the superimposition is at least 0.5 to enhance a color uniformity over a plurality of viewing positions.

12. The LED package of claim 11, wherein said ratio is at least 0.80.

13. The LED package of claim 11, further comprising a phosphor component (206) encapsulating said at least one LED, wherein said color uniformity is provided for light output from said phosphor component.

14. The LED package of claim 13, wherein said at least one LED is a plurality of LEDs encapsulated by said phosphor component.

15. An LED apparatus (400) comprising a plurality of LED packages (406) including the LED package of claim 11 and at least one additional LED package, wherein the at least one additional LED package is configured such that an other superimposition of said LED package of claim 11 with the at least one additional package results in a ratio of an area occupied by any of the LEDs in the other superimposition to an area unoccupied by any of the LEDs in the other superimposition that is at least 0.5 to provide the enhanced color uniformity over the plurality of viewing positions.

16. The LED apparatus of claim 15, wherein each of the at least one additional LED package has said particular configuration and wherein the LED package of claim 11 and the at least one additional LED package are oriented differently in said LED apparatus.

17. The LED apparatus of claim 15, wherein the least one additional LED package includes at least one LED that has a configuration that is different from the particular configuration of the LED package of claim 11.

18. The LED apparatus of claim 15, further comprising:

a system of lenses (404), wherein each lens of the system is disposed over a different one of said plurality of LED packages and wherein the color uniformity is provided for light output from said system of lenses.

19. A light-emitting diode (LED) package (812) comprising:

a plurality of LEDs (107), wherein each of the LEDs includes a respective cathode, anode and electroluminescent material between the cathode and the anode, wherein the LEDs are positioned and oriented in a particular configuration (804d) of the LEDs that is asymmetric with respect to any axis that is parallel to primary light-emitting surfaces of said plurality of LEDs in said package to provide an enhanced color uniformity over a plurality of viewing positions.

20. The LED package of claim 19, further comprising a phosphor component (206) encapsulating said plurality of LEDs, wherein said color uniformity is provided for light output from said phosphor component.

21. An LED apparatus (400) comprising a plurality of LED packages (406) including the LED package of claim 19 and at least one additional LED package, wherein the at least one additional LED package includes a respective plurality of LEDs that are positioned and oriented in a respective configuration (804d) of the respective plurality of LEDs that is asymmetric with respect to any axis that is parallel to primary light-emitting surfaces of said respective plurality of LEDs in said additional package to provide the enhanced color uniformity over the plurality of viewing positions.

22. The LED apparatus of claim 21, wherein each of the at least one additional LED package has said particular configuration and wherein the LED package of claim 19 and the at least one additional LED package are oriented differently in said LED apparatus.

23. The LED apparatus of claim 21, wherein the least one additional LED package has a configuration of the respective plurality of LEDs that is different from the particular configuration of the LED package of claim 18.

24. The LED apparatus of claim 21, further comprising:

a system of lenses (406), wherein each lens of the system is disposed over a different one of said plurality of LED packages and wherein the color uniformity is provided for light output from said system of lenses.