Note: Descriptions are shown in the official language in which they were submitted.
<br/> CA 02452348 2003-12-08<br/> MBMFile No. 1037-104<br/> SYSTEM AND METHOD FOR MANIPULATING ILLUMINATION<br/> CREATED BY AN r~RRAY OF LIGHT EMITTING DEVICES<br/> FIELD OF THE INVENTION<br/>The present invention pertains to the field of optical systems and in <br/>particular to an optical<br/>system incorporating solid-state light emitting devices configured in an <br/>array.<br/> BACKGROUND<br/>Recent innovations in LED design and manufacturing have led to the <br/>introduction of high-<br/>brightness LEDs that produce sufficient luminous flux for architectural and <br/>entertainment<br/>lighting applications. LEDs with different wavelength ranges, for example, <br/>red, green, and blue,<br/>have been combined in arrays with ancillary refractive optics to generate user-<br/>specified colours.<br/>An example of this type of configuration is the Space Cannon MetamorphosisT"" <br/>(Space<br/>Cannon vH, Fubine, Italy), wherein an array of red, green, and blue LEDs with <br/>individual<br/>moulded plastic optics, produces a narrow beam of coloured or white light. An <br/>example of a<br/>device that can produce a broad "wash" of coloured or white light is the Color <br/>Kinetics<br/>ColorBlastT"" 12 (Color Kinetics, Boston MA), which provides an array of red, <br/>green, and blue<br/>LEDs 20 mounted behind a frosted or clear tempered glass panel 40, as <br/>illustrated in Figure 1.<br/>The object of these light fixtures is to provide a narrow or broad <br/>distribution of light that has a<br/>uniform colour. However, the arrays of LEDs associated with these particular <br/>products consist of<br/>clusters of individual red, green, and blue LEDs that are ,provided in order <br/>to enable the<br/>satisfactory blending of the individually produced colours, thereby producing <br/>a user-specified<br/>colour on the illuminated surfaces. If, however, the LEDs are arranged in <br/>linear rows of sepaxate<br/>colours, the projected beam of light typically exhibits objectionable colour <br/>gradients at its edges.<br/>In addition, surfaces being illuminated using the above mentioned devices, <br/>that have occluding<br/>objects thereon, results in strong colour banding being visible on the <br/>illuminated surface due to<br/>the shadow cast by this occluding object.<br/>2<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/>In addition, the above devices can include moulded plastic optics 30, as <br/>illustrated in Figure 2,<br/>associated with each of the LEDs 20 to provide the control of the <br/>illumination. However these<br/>types of optics are bulky and relatively expensive to manufacture. <br/>Furthermore, these forms of<br/>refractive optics are unable to preferentially redirect emitted illumination <br/>in an off axis direction,<br/>with respect to the plane of the array of LEDs, however this is possible if <br/>the LEDs are mounted<br/>at an angle with respect to the plane of the array. In order to enable this <br/>type of mounting, each<br/>LED could be mounted and wired separately to enable this form or orientation, <br/>however this<br/>would preclude the use of a common circuit board for the mounting of the LEDs, <br/>as is a current<br/>standard, thereby resulting in a more costly device.<br/>A further disadvantage of the prior art is that red, green and blue LEDs <br/>typically require different<br/>drive voltages and can produce ranging colours of light, as such binning of <br/>LEDs is typically<br/>performed, in order to ensure a uniform illumination colour being produced by <br/>an array of LEDs.<br/>As such, LED manufacturers typically offer pre-assembled linear arrays of <br/>single colour LEDs<br/>with matched colours. For example, the Lumileds Line of products (Lumileds <br/>Lighting LLC,<br/>San Jose CA) comprise twelve high-brightness LEDs mounted in a row on a common <br/>printed<br/>circuit board. As has been previously mentioned, linear axrays of LEDs are <br/>difficult to<br/>incorporate into current lighting devices due to the problems of colour <br/>gradients and colour<br/>banding.<br/>The prior art comprises a number documents that define the design and method <br/>of use of<br/>reflector arrays. For example, United States Patent Nos. 6,260,981 and <br/>6,439,736 both define a<br/>luminaire designed to be suitable for suspended ceilings, wherein the design <br/>of this luminaire<br/>enables an improved packing density of these products during shipping. The <br/>reflector is<br/>designed having a grid pattern with a tapered design that allows these <br/>reflectors to be stored and<br/>transported such that one reflector nested within another thereby conserving <br/>space.<br/>United States Patent No. 6,234,643 provides a lighting fixture for reducing <br/>glare and dark spots<br/>on ceilings and walls through the use of direct and indirect reflectors. This <br/>lighting fixture<br/>includes first and second sets of elongated, parallel, spaced apart reflectors <br/>that intersect at a<br/>ninety-degree angle thereby forming an open reflector grid. In addition, the <br/>lighting fixture<br/>3<br/><br/> CA 02452348 2003-12-08<br/> MBMFile No. 1037-104<br/>includes a plurality of indirect reflectors connected to the outside walls of <br/>the open reflector grid<br/>which provide a means for reducing glare and dark spots on the ceiling and <br/>walls, which can be<br/>caused by the plurality of fluorescent lamps in the louver housing. This <br/>lighting fixture is<br/>designed specifically for use with fluorescent lamps and as such does not <br/>provide a means for<br/>manipulating the illumination provided by a plurality of discrete light <br/>sources that produce<br/>different wavelengths of illumination.<br/>In addition, the design and method of making an array of optoelectronic <br/>devices is provided in<br/>United Patent No. 5,660,461. The array of LED is formed .from a plurality of <br/>modular units,<br/>wherein a modular unit comprises a light emitting diode and a moulded <br/>reflector unit that has a<br/>cone shape. In order to assemble the array of optoelectronic devices, a <br/>plurality of the modular<br/>units are interconnected by a mechanical snap type connection. As such the <br/>modular units are<br/>fabricated individually and the use of a plurality of LEDs on a linear printed <br/>circuit board, as is<br/>common practice in the art, would not be applicable for this type of design.<br/>The prior art further comprises a number of documents that disclose diffusers <br/>that are used for<br/>blending or distributing illumination in a plurality of directions. For <br/>example, United States<br/>Patent No. 6,447,133 provides an illumination member having a diffuser that <br/>has therein a<br/>plurality of spheres or particles that have a different refractive index when <br/>compared to the<br/>diffuser material itself. As such, the illumination on the output face of the <br/>diffuser can be<br/>controlled by varying the number, size and homogeneity of these spheres or <br/>particles.<br/>Specifically, this diffuser has been designed such that is can be a few <br/>millimetres thick and have<br/>the ability to emit a homogeneously distributed luminance on its output face. <br/>This type of<br/>diffuser is specifically designed for use with a LCD display and provides a <br/>means for controlling<br/>the illumination there from. However this diffuser has not been designed to <br/>provide the blending<br/>of colours produced by a plurality of discrete light sources in close <br/>proximity.<br/>United States Patent No. 6,241,363 provides a coloured light mixing device <br/>that can be<br/>associated with at least one light source set, such that the light source set <br/>has three light<br/>generating units that generate light of different colours. The coloured light <br/>mixing device<br/>comprises a colour mixing plate that is made of transparent material and has a <br/>lower surface that<br/>4<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/>has a lower wavelike pattern thereon that faces the light source set, and an <br/>opposite upper surface<br/>that has an upper wavelike pattern thereon. In addition, the upper wavelike <br/>pattern is oriented<br/>differently from the lower wavelike pattern. Upon being hit by light from the <br/>light source set, the<br/>lower wavelike pattern acts as a plurality of linear light sources for mixing <br/>light colours inside<br/>the colour mixing plate and the upper wavelike pattern thereby emits light of <br/>uniform intensity<br/>and mixed hue. This design of a diffuser enables colour mixing specifically <br/>designed for the<br/>situation where there is close proximity between the various colours of light <br/>and therefore may<br/>not be effective in blending illumination produced by a first strip of light <br/>emitting devices<br/>producing a first colour that is flanked by a second strip producing a <br/>different illumination<br/>colour.<br/>Finally, United States Patent No. 6,264,346 provides an apparatus for mixing <br/>light from different<br/>coloured LEDs. This apparatus comprises a faceted diffusive layer that is used <br/>to mix light from<br/>an LED array and is more specifically designed for the creation of white light <br/>from these<br/>different coloured LEDs. This type of apparatus essentially directs all of the <br/>illumination from<br/>the multiple different coloured light emitting diodes in the same direction <br/>thereby combining<br/>them to form the desired illumination colour, namely white light. .<br/>Therefore there is a need for a new method and apparatus for the manipulation <br/>of illumination<br/>created by an array of light emitting devices that is capable of reducing <br/>colour gradients and<br/>colour banding in addition to being optically efficient and capable of <br/>illumination distribution in<br/>an off axis direction of the light emitting device array, while being <br/>applicable for use with strips<br/>of single coloured light emitting devices, as are commonly produced in the <br/>industry.<br/>This background information is provided for the purpose of making known <br/>information believed<br/>by the applicant to be of possible relevance to the present invention. No <br/>admission is necessarily<br/>intended, nor should be construed, that any of the preceding information <br/>constitutes prior art<br/>against the present invention.<br/>5<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/> SUMMARY OF THE INVENTION<br/>An object of the present invention is to provide a system and method for <br/>manipulating<br/>illumination created by an array of light emitting devices. In accordance with <br/>an aspect of the<br/>present invention, there is provided a system for manipulating illumination <br/>created by an<br/>array of light emitting devices, said system comprising: a plurality of light <br/>emitting devices<br/>spatially arranged in an array, said array separated into one or more <br/>sections, wherein each<br/>section of the array includes light emitting devices capable of creating <br/>illumination having a<br/>predetermined wavelength range; a macroscopic optical system adjacent to the <br/>plurality of<br/>light emitting devices, said macroscopic optical system enabling redirection <br/>of the<br/>illumination created by the plurality of light emitting devices; and a <br/>microscopic optical<br/>system for diffusing the illumination created by the plurality o~ light <br/>emitting devices<br/>subsequent to the redirection by the macroscopic optical system, thereby <br/>providing a desired<br/>level of blending of the predetermined wavelengths ranges.<br/>In accordance with another aspect of the invention, there is provided a method <br/>for<br/>manipulating illumination created by an array of light; emitting devices, said <br/>method<br/>comprising the steps of redixecting the illumination using reflective optics <br/>formed in a grid<br/>pattern; diffusing the redirected illumination thereby blending the redirected <br/>illumination to<br/>create a desired illumination effect, said diffusing retaining a desired <br/>angular distribution of<br/>the illumination created by the reflective optics.<br/> BRIEF DESCRIPTION OF THE FIGURES<br/>Figure 1 illustrates a prior art configuration wherein illumination from a <br/>light emitting diode is<br/>manipulated by a diffuser panel.<br/>Figure 2 illustrates another prior art configuration wherein illumination <br/>created by a light<br/>emitting diode is manipulated by a moulded refractive optic.<br/>Figure 3 illustrates a ray diagram and the associated vertical cross sectional <br/>view of a<br/>configuration including a macroscopic optical system and a microscopic optical <br/>system used<br/>6<br/><br/> CA 02452348 2003-12-08<br/> MBM Fide No. 1037-104<br/>together to manipulate illumination created by a plurality of light emitting <br/>devices, according to<br/>one embodiment of the present invention.<br/>Figure 4 illustrates a horizontal cross sectional view of the configuration <br/>including a macroscopic<br/>optical system and a microscopic optical system used together to manipulate <br/>illumination created<br/>by a plurality of light emitting devices, according to the embodiment <br/>illustrated in Figure 3.<br/>Figure 5 illustrates a ray diagram and the associated vertical cross sectional <br/>view of a<br/>configuration including a macroscopic optical system and a microscopic optical <br/>system used<br/>together to manipulate illumination created by a plurality of light emitting <br/>devices, according to<br/>one embodiment of the present invention.<br/>Figure 6 illustrates a horizontal cross sectional view of the conj~guration <br/>including a macroscopic<br/>optical system and a microscopic optical system used together to manipulate <br/>illumination created<br/>by a plurality of light emitting devices, according to the embodiment <br/>illustrated in Figure 5.<br/>Figure 7 illustrates a ray diagram indicating light interaction with a <br/>macroscopic optical system<br/>according to one embodiment of the present invention.<br/>Figure 8 illustrates a ray diagram indicating light interaction with a <br/>macroscopic optical system<br/>according to another embodiment of the present invention.<br/>Figure 9 illustrates an array of light emitting devices having a macroscopic <br/>optical system and<br/>microscopic optical system designed for manipulating light in a predominantly <br/>horizontal<br/>direction, according to one embodiment of the present invention.<br/>Figure 10 is a cross sectional view of the macroscopic optical system <br/>illustrated in Figure 9, as<br/>taken along A-A.<br/>Figure 11 is a cross sectional view of the macroscopic optical system <br/>illustrated in Figure 9, as<br/>taken along B-B.<br/>7<br/><br/>CA 02452348 2003-12-08<br/> MBM File No. 1037-104<br/>Figure 12 is a candela distribution of illumination created by a device having <br/>the elements as<br/>illustrated in Figure 9.<br/>Figure 13 illustrates an array of light emitting devices having a macroscopic <br/>optical system and<br/>microscopic optical system designed for manipulating light in a predominantly <br/>vertical direction,<br/>according to one embodiment of the present invention.<br/>Figure 14 is a cross sectional view of the macroscopic optical system <br/>illustrated in Figure 13, as<br/>taken along C-C.<br/>Figure 15 is a cross sectional view of the macroscopic optical system <br/>illustrated in Figure 13, as<br/>taken along D-D.<br/>Figure 16 is a candela distribution of illumination created by a device having <br/>the elements as<br/>illustrated in Figure 13.<br/> DETAILED DESCRIPTION OF THE INVENTION<br/> Definitions<br/>The term "light emitting device" or "LED" are used interchangeably to define <br/>any form of solid-<br/>state light device enabling the creation of illumination or irradiation, which <br/>includes infrared<br/>radiation, visible light, and ultraviolet radiation.<br/>The term "array" is used to define a geometric layout defining the placement <br/>and arrangement of<br/>light emitting devices. This geometric layout can be one dimensional, for <br/>example linear, or two<br/>dimensional, for example planax.<br/>Unless defined otherwise, all technical and scientific terms useal herein have <br/>the same meaning as<br/>commonly understood by one of ordinary skill in the art to which this <br/>invention belongs.<br/>8<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/>The present invention provides an illumination optical system that enables the <br/>direction and<br/>mixing of light from light emitting devices. The optical system comprises a <br/>plurality of light<br/>emitting devices that are spatially arranged in an array, wherein this array <br/>comprises one or more<br/>sections, such that the light emitting devices in a particular section emit <br/>light within a<br/>predetermined wavelength range. Through the use of a combination of <br/>macroscopic and<br/>microscopic optical systems, the illumination created by the array can be <br/>manipulated such that a<br/>desired illumination distribution is created. The macroscopic; optical system <br/>provides a means<br/>for redirecting the illumination in one or more desired directions, wherein <br/>this redirection is<br/>provided by a collection of appropriately shaped and positioned reflective <br/>optics. Subsequent to<br/>its interaction with the macroscopic optical system, the illumination is <br/>manipulated by a<br/>microscopic optical system that enables the diffusion of the illumination in a <br/>predetermined<br/>manner, while retaining the desired angular distribution of the illumination <br/>created by the<br/>macroscopic optical system. Through the appropriate design and orientation of <br/>both the<br/>macroscopic and microscopic optical systems, a desired illumination effect can <br/>be created.<br/> Macroscopic Optical System<br/>The macroscopic optical system provides a means for redirecting the <br/>illumination created by the<br/>point source light emitting devices in one or more desired directions. This <br/>redirection of the<br/>illumination is enabled by a collection of appropriately shaped and positioned <br/>reflective optics<br/>that can preferentially and efficiently redirect light from the light emitting <br/>diodes with a greater<br/>level of efficiency when compared to the use of moulded refractive optics.<br/>The macroscopic optical system is typically designed having reference to a <br/>grid or orthogonal<br/>type pattern and as such, depending on the design of the macroscopic optical <br/>system, the<br/>reflective optics can be oriented in one or both of these orthogonal <br/>directions. Depending on the<br/>design of the reflective optics, the illumination created by the light <br/>emitting devices can be<br/>redirected in a variety of predetermined manners. The following description of <br/>the present<br/>invention, defines the reflective optics associated with the macroscopic <br/>optical system as having<br/>a vertical or horizontal orientation, for ease of understanding. However, it <br/>is to be readily<br/>understood that this type of definition of the orientation of the reflective <br/>optics associated with<br/>9<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/>the macroscopic optical system is not limiting, since a rotation of the grid <br/>pattern results in<br/>reflective optics being oriented in a direction other than horizontal or <br/>vertical.<br/>Each embodiment of the macroscopic optical system comprises a plurality of <br/>horizontal<br/>reflectors or reflective optics that enable the preferential redirection of <br/>illumination into the<br/>desired upper portion of the hemispherical luminous intensity distribution of <br/>the light emitting<br/>devices. In this manner an elevated amount of the illumination provided by the <br/>finite number of<br/>light emitting devices within the array can be used to create the desired <br/>illumination effect.<br/>In one embodiment of the present invention the shape, placement and design of <br/>the reflective<br/>optics within the macroscopic optical system can enable a predominantly <br/>horizontal type of<br/>spread of the illumination created by the light emitting devices. In this <br/>embodiment of the<br/>invention, planar horizontal reflective optics are provided adjacent to the 1 <br/>or more light emitting<br/>devices in a particular row of the array. Figure 3 and Figure 4 illustrate a <br/>vertical cross section<br/>and horizontal cross section of the optical system according to this <br/>embodiment, respectively.<br/>While these figures illustrate a planar array of light emitting devices, for <br/>example 9 in. total, the<br/>array can equally be linear in design and the macroscopic optical system would <br/>be designed to<br/>suit this shape of array.<br/>Having regard to Figures 3 and 4, the horizontal reflective optics 50, provide <br/>a moderate off axis<br/>distribution of the illumination with a wide beam spread in the vertical <br/>direction. The horizontal<br/>reflective optics include a slot 60 in the upper edge, wherein this slot <br/>allows illumination to<br/>propagate unimpeded into the desired upper portion of the hemispherical <br/>luminous intensity<br/>distribution of the light emitting devices: As illustrated in Figure 3, there <br/>are essentially three<br/>forms of light rays, namely an unobstructed ray 70, a reflected ray, 80 and an <br/>unobstructed slot<br/>ray 90 that together form the illumination that subsequently interacts with <br/>the microscopic optic<br/>system 100.<br/>The slot 60 in the horizontal reflective optics of this embodiment can be <br/>designed having a<br/>number of different shapes, widths and depths, wherein these features of the <br/>slot are determined<br/>based on the luminous intensity distribution and luminous area of the light <br/>emitting devices and<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/>the packaging thereof. The packaging of the light emitting devices can include <br/>refractive optics<br/>that are integral to the light emitting device itself, thereby varying the <br/>packaging associated with<br/>a light emitting device will alter the dispersion of the illumination created <br/>thereby. In order to<br/>determine the optimum geometrical characteristics of the slot, computer ray <br/>tracing techniques<br/>can be used, wherein this technique can take into account the desired <br/>illumination effect together<br/>with the illumination characteristics of a particular type of light emitting <br/>device.<br/>In another embodiment of the present invention the shape, placement and design <br/>of the reflective<br/>optics within the macroscopic optical system can enable a predominantly <br/>vertical type of spread<br/>of the illumination created by the light emitting devices. In this embodiment <br/>of the invention,<br/>linear, tilted and curved horizontal reflective optics are provided adjacent <br/>to the I or more light<br/>emitting devices in a particular row of the array. In addition, curved <br/>vertical reflective optics are<br/>provided adjacent to either side of the 1 or more light emitting devices in a <br/>particular column of<br/>the array which together form a trough surrounding the light emitting device <br/>in the vertical<br/>direction. Figure 5 and Figure 6 illustrate a vertical cross section and <br/>horizontal cross section of<br/>the optical system according to this embodiment, respectively. While these <br/>figures illustrate a<br/>planar array of light emitting devices, the array can equally be linear in <br/>design and as such the<br/>macroscopic optical system would be designed to suit this type of array.<br/>Having specific regard to Figures 5 and 6, the tilted and curved horizontal <br/>reflective optics 120<br/>provide strong off axis distribution of illumination and further producing a <br/>narrow beam spread<br/>in the vertical direction. Additionally, the curved vertical reflective optics <br/>130 on either side of a<br/>particular light emitting device form a trough and provide a narrow horizontal <br/>beam spread of the<br/>illumination. As an example, this form of narrow horizontal beam spread can be <br/>useful in wall<br/>illumination scenarios. As illustrated in Figure 5, there are essentially two <br/>forms of light rays,<br/>namely an unobstructed ray 70 and a reflected ray, 80 that together form the <br/>illumination that<br/>subsequently interacts with the microscopic optic system 100.<br/>In one embodiment of the invention, the vertical reflective optics 130 are <br/>shaped such that they<br/>create a parabolic trough that surrounds a column of light emitting devices as <br/>illustrated in<br/>Figure 6. This form of vertical reflective optics provides a means for <br/>limiting the Horizontal<br/>11<br/><br/> CA 02452348 2003-12-08<br/> MBM File No. 1037-104<br/>spread of illumination. In this manner a greater percentage of the <br/>illumination created by the<br/>finite number of light emitting devices can be directed towards the <br/>microscopic optical system.<br/>Additionally, the horizontal reflective optics 120 are shaped as an oft=axis <br/>parabola as illustrated<br/>in Figure 5, thereby directing the illumination created by the light emitting <br/>devices i"n a more<br/>vertical direction as indicated by the ray traces 80. According to one <br/>embodiment, the vertical<br/>and horizontal reflective optics can be shaped such that they form a compound <br/>parabolic<br/>concentrator as described by Welford et al, in High Collection Nonimaging <br/>Optics, San<br/>Francisco, Academic Press, 1980. In addition, small modifications in the <br/>curvature, tilt angle,<br/>and position of the horizontal reflectors, in relation to the light emitting <br/>devices, can. alter the<br/>vertical distribution of the illumination emitted by the light emitting <br/>devices, thereby enabling<br/>one to accommodate specific luminous intensity distribution requirements.<br/>The packaging of the light emitting devices can include refractive optics that <br/>are integral to the<br/>light emitting device itself, thereby varying the packaging associated with a <br/>light emitting device<br/>will alter the dispersion of the illumination created thereby. In order to <br/>determine the optimum<br/>geometrical characteristics of the slot, computer ray tracing techniques can <br/>be used, wherein this<br/>technique can take into account the desired illumination effect together with <br/>the illumination<br/>characteristics of a particular type of light emitting device.<br/>In one embodiment of the invention, the reflective optics of the macroscopic <br/>optical system are<br/>fabricated from specular aluminium, a metallised plastic or other form of <br/>stiff reflective material<br/>as would be readily understood by a worker skilled in the art. As an example, <br/>reflective optics<br/>fabricated from a specular aluminium material can provide approximately 95% <br/>efficiency of<br/>illumination redirection.<br/> Microscopic Optical System<br/>Subsequent to interaction with the macroscopic optical system, the <br/>illumination is manipulated<br/>by a microscopic optical system that provides for the diffusion of the <br/>illumination in the desired<br/>manner while retaining control of the desired angular distribution created by <br/>the macroscopic<br/>optical system.<br/>12<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/>In one embodiment of the invention, the microscopic optical system <br/>preferentially diffuses light<br/>in the horizontal direction, thereby providing a means for blending <br/>illumination emitted from<br/>columns of light emitting devices. This feature can be advantageous when the <br/>illumination from<br/>various columns of light emitting devices are of varying wavelengths, for <br/>example, red, green,<br/>and blue LEDs. In addition, the horizontal diffusion provided by the <br/>microscopic optical system<br/>can enable the reduction of the appearance of high brightness or illumination <br/>"hot spots" which<br/>can result from the illumination of an area using point light sources like <br/>light emitting devices.<br/>For example, the microscopic optical system can be a holographic diffuser with <br/>a linear or<br/>elliptical distribution, a mechanically-produced plastic diffuser, a <br/>lenticular array or any other<br/>form of diffuser having horizontal diffusion characteristics as would be <br/>readily understood by a<br/>worker skilled in the art. As examples, a suitable holographic diffuser is <br/>called a Light Shaping<br/>Diffuserr"" which is produced by Physical Optics Corporation, Torrance, CA, a <br/>suitable<br/>mechanically-produced plastic diffuser is a Rosco Tough SilkT"", produced by <br/>Rosco Laboratories<br/>Inc., Stamford, CT), and a suitable lenticular array is produced by Fresnel <br/>Technologies Inc., Fort<br/>Worth, TX. While these are examples of suitable microscopic optical systems <br/>enabling<br/>horizontal diffusion of the illumination, a plurality of other devices having <br/>similar characteristics<br/>to those defined would be suitable for integration into the illumination <br/>optical system according<br/>to the present invention.<br/>In another embodiment of the invention, the microscopic optical system <br/>diffuses light evenly in<br/>all directions, wherein diffusers such as a holographic diffuser with circular <br/>distributions, frosted<br/>or sandblasted glass, plastic diffuser, lenslet array or other form of <br/>diffuser having this type of<br/>diffusion characteristic, as would be readily understood by a warker skilled <br/>in the art.<br/>Figures 3 and 5 illustrate ray diagrams representing the illurr,~ination <br/>subsequent to interaction<br/>with a microscopic optical system in the form of a diffixser 100 according to <br/>. different<br/>embodiments of the present invention. As an example, with reference to Figure <br/>5, it can be seen<br/>that the microscopic optical system, in the form of a diffuser 100, is <br/>designed to retain the desired<br/>angular distribution of the illumination previously created by the macroscopic <br/>optical system.<br/>13<br/><br/> CA 02452348 2003-12-08<br/> MBMFile No. 1037-104<br/>Figure 7 illustrates the diffusion of an incident ray 140 by a diffuser 100, <br/>wherein the diffused<br/>light 160 is manipulated in a predominantly horizontal manner. Additionally, <br/>Figure 8 illustrates<br/>an incident ray being manipulated such that the illumination or diffused light <br/>150, is diffused in a<br/>predominantly vertical manner.<br/>In one embodiment, holographic diffusers are used as the microscopic optical <br/>system as they<br/>typically have high transmittance of approximately 80 to 90%, which is more <br/>efficient than<br/>frosted glass or plastic diffusers which have a transmittance of approximately <br/>30 to 70%.<br/> Light Emitting Devices<br/>The present invention can be associated with a plurality of light emitting <br/>devices that are<br/>arranged in an array. These light emitting devices can produce any number of <br/>illaxmination<br/>wavelengths and can be arranged in a variety of orders or patterns within the <br/>array. For example,<br/>the plurality of light emitting devices are capable of producing wavelengths <br/>of illumination<br/>including red, green and blue, for example, thereby upon the blending thereof <br/>can enable almost<br/>any colour of illumination to be created. In addition, one or more amber light <br/>emitting devices<br/>can be integrated into the array in order to enhance the colour gamut together <br/>with colour<br/>rendering properties of the array.<br/>In one embodiment of the invention, the light emitting devices are <br/>manufactured on a printed<br/>circuit board. Light emitting devices of different colours require different <br/>drive voltages in<br/>addition to having varying illumination colour creation even within the same <br/>colour band. As<br/>such, the lighting industry performs an organisation routine, typically <br/>referred to as binning, in<br/>order to ensure a uniform illumination colour is being produced by a <br/>collection of light emitting<br/>devices. As such, manufacturers typically offer pre-assembled arrays of single <br/>colour light<br/>emitting devices with matched colours. These forms of arrays can readily be <br/>used in the<br/>illumination optical system according to the present invention. Optionally, a <br/>two dimensional<br/>printed circuit board can be used.<br/>14<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/> EXAMPLES<br/>EXAMPLE l: Optical System for Predominantly Horizontal Distribution of <br/>Illumination<br/>In one embodiment of the present invention, the illumination optical system is <br/>designed for a<br/>predominantly horizontal distribution of the illumination created by the light <br/>emitting devices.<br/>Figure 9 illustrates three components of an optical system meeting this <br/>criterion, wherein the<br/>optical system comprises a two dimension array of light emilting devices 205 <br/>on collection of<br/>aligned linear printed circuit boards, 200, a macroscopic optical system 210 <br/>incorporating<br/>horizontal reflective optics 310 and a microscopic optical system 220 in the <br/>form of a diffuser.<br/>Cross sections A-A and B-B of the illumination optical system are illustrated <br/>in Figures 10<br/>and 1 l, respectively. While the cross section is identified on the <br/>macroscopic optical system, the<br/>cross section illustrates a cross section of the three components together.<br/>The macroscopic optical system that includes a plurality of horizontal planar <br/>reflective optics<br/>aligned with the rows of light emitting devices provides a moderate off axis <br/>distribution of the<br/>illumination, further including a wide beam spread in the vertical direction. <br/>With regard to<br/>Figure 11, the horizontal reflective optics 310 include a trapezoidal slot 320 <br/>centred on each light<br/>emitting device, wherein this form of the slot provides a means for allowing <br/>emitted light to<br/>propagate unimpeded into the desired upper portion of the hemispherical <br/>luminous intensity<br/>distribution of light emitting devices. Upon interaction with the macroscopic <br/>optical system the<br/>illumination is diffused by the microscopic optical system 220, providing a <br/>wide horizontal beam<br/>spread which can be applicable for surface illumination applications.<br/>Figure 12 illustrates the luminous distribution of an illumination system <br/>designed in this manner.<br/>EXAMPLE 2: Optical System for Predominantly Vertical Distribution of <br/>Illumination<br/>In one embodiment of the present invention, the illumination optical system is <br/>designed for a<br/>predominantly vertical distribution of the illumination created by the light <br/>emitting devices.<br/>Figure 13 illustrates three components of an optical system meeting this <br/>criteria, wherein the<br/>optical system comprises a two dimension array of light emitv~ing devices 205 <br/>on collection of<br/><br/> CA 02452348 2003-12-08<br/> MBMFiIe No. 1037-104<br/>aligned linear printed circuit boards, 200, a macroscopic optical system 230 <br/>incorporating tilted<br/>and curved horizontal reflective optics 340 and vertical parabolic trough <br/>reflective optics 330,<br/>together with a microscopic optical system 240 in the form of a diffuser. <br/>Cross sections C-C and<br/>D-D of the illumination optical system are illustrated in Figures 14 and 15, <br/>respectively. While<br/>the cross section is identified on the macroscopic optical system, the cross <br/>section illustrates a<br/>cross section of the three components together.<br/>The macroscopic optical system that includes a plurality of horizontal <br/>reflective optics 340 that<br/>are tilted and curved in order to provide strong off axis distribution of the <br/>illumination, while<br/>having a narrow beam spread in the vertical direction. The macroscopic optical <br/>system further<br/>comprises a plurality of vertical reflective optics 330 that are in the form <br/>of a parabolic trough,<br/>thereby providing a means for minimising the horizontal spread of the <br/>illumination. Upon<br/>interaction with the macroscopic optical system the illumination is diffused <br/>by the microscopic<br/>optical system 240 in the form of a diffuser that provides a means retaining <br/>the desired angular<br/>1 S distribution of the illumination created by the macroscopic optical <br/>system.<br/>Figure 16 illustrates the luminous distribution of an illumination system <br/>designed in this manner.<br/>The embodiments of the invention being thus described, it will be obvious that <br/>the same may be<br/>varied in many ways. Such variations are not to be regarded as a departure <br/>from the spirit and<br/>scope of the invention, and all such modifications as would be obvious to one <br/>skilled in the art<br/>are intended to be included within the scope of the following claims.<br/>16<br/>
