Abstract:
A high intensity mutli-wavelength illumination apparatus comprising an array of LEDs each of which has a predetermined spectral output that is emitted over a predetermined solid angle, an array of non-imaging concentrators the individual non-imaging concentrators of which are optically coupled in one-to-one correspondence with the LEDs, each non-imaging concentrator in the array of non-imaging concentrators operating to collect radiation emitted by each of the LEDs and to re-emit substantially all the collected radiation as a beam having a diverging solid angle smaller than said predetermined solid angle over which radiation is emitted by each of the LEDs, the non-imaging concentrators each having an entrance aperture for receiving radiation emitted by a corresponding one of the LEDs and an exit aperture from which the LEDs output emerges spatially and spectrally uniform in the near field of the exit aperture, and a light integrator having an entrance facet optically coupled to each of the exit apertures of the non-imaging concentrators for receiving radiation there through and conducting it to an exit facet thereof from which radiation is emitted for a downstream application, the light integrator being structured and arranged to substantially uniformly mix the individual beams emitted by each concentrator so that radiation emitted from its exit facet is uniformly colored.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional of U.S. patent application Ser. No. 10/334,525 filed on Dec. 30, 2002 now U.S. Pat. No. 7,153,015 bearing the title, LED WHITE LIGHT OPTICAL SYSTEM, the entire contents of which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates to a white-light optical system, and more particularly, to a LED white-light optical system that provides spatially uniform high intensity white light over a near field diverging region in a highly efficient manner. 
   BACKGROUND OF THE INVENTION 
   Many optical energy applications require high intensity, spatially uniform, white light that does not significantly heat the surrounding environment in the near field and/or far field. More specifically, many applications require correlated color temperatures between 4100-4900K (i.e., white light) with a color rendering index (“CRI”) between 90 to 100. 
   Correlated color temperature (“CCT”) is a numerical assignment of the apparent color of a light source (i.e., as viewed by the human visual system) and is measured in degrees Kelvin. Color rendering is how well a light source renders color (i.e., in the course of interacting with an object) as compared to how well daylight renders color (i.e., in the course of interacting with the same object). 
   Traditional light sources, however, suffer from, for example, but not limited to, combinations of a poor CRI, poor CCT, poor intensity, short usage life, large power electrical consumption, large package size, thermal energy, and/or are electrically and; or optically inefficient. 
   Tungsten filament lamps. for example, while providing high intensity optical energy with high CRI values, emit optical energy that has a poor CCT (i.e., about 3000K. which correlates to the color yellow) for white light applications. In addition. tungsten filament lamps have a low electrical to optical efficiency and, thus, require large amounts of electrical power to generate high intensity optical energy, which results in large quantities of thermal energy. Furthermore. high power tungsten lamps have a low lamp lifetime, usually operating for about 500 hours. 
   Tungsten-halogen lamps, when used in conjunction with filters, produce a CCT of above 4000K but still suffer from many of the same disadvantages of Tungsten filament lamps. 
   Metal halide lamps have a high luminous efficiency (“electric energy” to “optical energy” efficiency) and produce optical energy with a CCT of around 5000K (bluish white), which is just above the white light range. However. Metal halide lamps also emit optical energy below and above the human visual system. The optical energy above the white light CCT range is referred to as infrared light. Infrared light optical energy is sensed as thermal energy or heat. The optical energy below the white light CCT range is referred to as ultra violet light and in many circumstances an unwanted or damaging by product. Xenon arc lamps provide optical energy with higher intensity than metal halide lamps. but have a low luminous efficiency and low lamp life time (around 500 hours). Furthermore, traditional light sources such as arc lamps, for example, when used as a light source for a less than spherical illumination region, are optically inefficient. The full spherical discharge of optical energy is difficult to capture into a particular illumination region. 
   A light emitting diode (“LED”) emits optical energy over specific CCT&#39;s within the white light CCT range. However, commercially available LED&#39;s that emit white light have low CCT and have poor control. In addition, LED&#39;s provide insufficient optical energy for most illumination applications. 
   An improved optical system is needed. 
   SUMMARY OF THE INVENTION 
   A preferred embodiment of the invention provides a LED lighting device that produces high intensity, spatially uniform, white light in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the white light is produced by using a phosphor layer in conjunction with a single LED. 
   An alternative embodiment of the invention provides a method for obtaining high intensity, spatially uniform, white light in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the white light is produced by using a phosphor layer in conjunction with a single LED. 
   A preferred embodiment of the invention provides an LED curing device that produces high intensity, spatially uniform, optical energy for curing in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the optical energy is produced by using single and multiple LED&#39;s. 
   A preferred embodiment of the invention provides a method for obtaining high intensity, spatially uniform, optical energy for curing in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the optical energy is produced by using single and multiple LED&#39;s. 
   A preferred embodiment of the invention provides a LED photo-dynamic therapy device that produces high intensity, spatially uniform, optical energy for photo-dynamic therapy in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the optical energy is produced by using single and multiple LED&#39;s and single and multiple concentrators. 
   A preferred embodiment of the invention provides a method for obtaining high intensity. spatially uniform, optical energy for photo-dynamic therapy in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the optical energy is produced by using single and multiple LED&#39;s and single and multiple concentrators. 
   An alternative embodiment of the invention provides a LED illumination device that produces high intensity, spatially uniform, white light in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the white light is produced by using an array of different color LEDs and single and multiple concentrators. 
   An alternative embodiment of the invention provides a method for obtaining high intensity, spatially uniform, white light in the near and far fields in a reduced package size that does not significantly heat the surrounding environment, wherein the white light is produced by using an array of different color LED&#39;s and single and multiple concentrators. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features of the invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
     In the drawings, wherein similar reference characters denote similar elements through the several views: 
       FIG. 1  illustrates a white light system according to a preferred embodiment of the invention, 
       FIG. 2  illustrates a flow diagram of the white light system according to a preferred embodiment of the invention, 
       FIG. 3  illustrates a LED curing system according to an alternative embodiment of the invention, 
       FIG. 4  illustrates a LED photo dynamic therapy system according to an alternative embodiment of the invention, and 
       FIG. 5  illustrates a multi-wavelength LED array illumination system  500  according to an alternative embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Applications, including, but not limited to, indication, illumination, curing, photo-dynamic therapy, scanning, etc., require optical energy with specific characteristics, such as, but not limited to, wavelength spectrum, a CCT range, a CRI value, angular distribution, intensity, and/or spatial distribution, high electrical-to-optical power conversion efficiency, etc. 
   Optical energy, in general, includes the optical wavelength spectrum from 100 nanometers wavelength to 20 microns wavelength and includes the visual light spectrum, the infrared spectrum, and the ultraviolet light spectrum. The visual light spectrum is from 380 nanometers wavelength to 750 nanometers wavelength, the infrared spectrum is from 700 nanometers wavelength to 20 microns wavelength and the ultraviolet spectrum is from 100 nanometers to 380 nanometers. The wavelength spectrum or spectrum width of optical energy refers to the wavelengths present within the optical energy. A uniform wavelength spectrum occurs when the wavelength spectrum is the same spectrum at each point within a region of the optical energy. 
   Intensity of optical energy is defined as the power per unit area. Thus, the intensity of optical energy in a diverging illumination pattern will decrease as the distance from the optical energy source increases (i.e., since the unit area increases). 
   Spatial distribution of optical energy is the intensity (as defined as power per unit area) at each point in a particular target area relative to the entire illuminated area. Uniform spatial distribution occurs when the optical energy per unit area is constant. 
   Angular distribution is the direction of the emitted optical energy. For example, the sun emits light over the entire area of the sun&#39;s surface. The area of a sphere equals 4π times the square of the radius. In optics, this is referred to as 4π steradians for a sphere and 2π steradians for a hemisphere. Thus the angular distribution of the sun is 4π steradians: However. light sources, other than the sun, emit light at less than 4π steradian, due to the geometry of creating or delivering the optical energy. An LED emits optical energy out the face (when the LED is encapsulated) of the LED into a hemisphere (i.e., 2π steradian). 
   Also, optical energy is defined as being in the near field or the far field. Optical energy is referred to as near field if the region of interest is within ten times the diameter of the source. Thus for an optical element with an exit aperture of ten millimeters, the near field is the region within 100 millimeters of the exit aperture and the far field is the region past 100 millimeters. 
   Optical energy systems utilize optical elements to manipulate, direct, filter, etc. optical energy to better prepare the optical energy for a particular application. Thus, between the optical energy source and the end application there may be multiple optical elements. Optical elements include any element capable of interacting with optical energy and can include elements such as, but not limited to, filters, reflectors, diffractors, refractors, aligners, lenses, concentrators, polarizers, micro-structures, etc. Four characteristics of an optical interaction include scatter, transmission, fluorescence and phosphorescence, absorption and reflection of the optical energy (i.e., photons). 
   Thus for example, optical energy interacting with a filter will scatter a percentage of the optical energy, transmit through the filter a percentage of optical energy, absorb a percentage of the optical energy, and reflect a percentage of the optical energy. The magnitude of these percentages is a function of the optical energy and of the filter. 
   Optical efficiency is the ratio of total optical power that reaches a desired target area to the total optical power initially received and/or created by a given optical system. 
   A preferred embodiment of the invention increases optical efficiency over conventional optical systems by utilizing index matching. The optical efficiency of an interface between a first and second medium is potentially affected by the index of refraction of each medium. Everything from air to optical element materials have an associated index of refraction. In order for there not be any optical energy loss, due to total internal reflection, the index of refraction of the second element must be equal to or less than the index of refraction of the first element, referred to as index matching. When there is no index matching, the amount of optical energy passed from the first element to the second element is reduced, thereby reducing the optical efficiency. 
   A preferred embodiment of the invention increases optical efficiency over conventional optical systems by utilizing flush connections. The optical efficiency of an interface between a first and second medium is potentially affected by flushness of the physical interface connection. Two optical elements are flush if there are no impurities or irregularities between the two attaching surfaces (also referred to as being in optical contact). A flush connection allows the optical energy to pass from one medium to a second medium without any loss of optical efficiency. 
   A preferred embodiment of the invention increases optical efficiency over conventional optical systems by geometrically matching optical elements. The optical efficiency of an interface between a first and second medium is potentially affected by the geometric shapes of each medium. A second medium entrance aperture shape that is the same or larger than a first medium exit aperture shape ensure that all the optical energy, when transmitting from a first medium exit aperture is captured by the second medium entrance aperture. 
   Referring to the drawings and in particular to  FIGS. 1-5 , there are shown preferred embodiments of the invention. 
     FIG. 1  illustrates a white light system  100  according to a preferred embodiment of the invention. The optical system  100  includes a LED optical source  110 , an optical filter  120 , a reflector  130 , a phosphor layer  135 , a concentrator  140 , a first illumination region  150 , a secondary optical element  160 , a second illumination region  170 , a target  180 , and a thermal dissipater  190 . 
   The LED optical source  110  provides optical energy. The LED optical source  110  includes optical material  115  with a front face  111  and back face  112 . 
   Electrical current is provided to the LED by power source (not shown). An LED provides optical energy at particular CCT ranges. When an electrical field is applied across a LED semiconductor junction, photons are released within the semiconductor material. The Photons emit in a 4π steradian angular distribution and exit the LED via the front and back face. The semiconductor material determines the CCT range of the created optical energy. 
   In a preferred embodiment of the invention, the LED optical source front face  111  emits optical energy over a 2π steradian distribution. In an alternative embodiment of the invention, the LED optical source back face  112  emits optical energy over a 2π steradian distribution. 
   In an alternative embodiment of the invention, LED optical source  110  is thermally connected to the thermal dissipater  190 . In an alternative embodiment, LED optical source  110  is any source that emits optical energy at the desired CCT range, at the desired optical energy level and over a 2π steradian distribution. 
   In a preferred embodiment of the invention, the LED optical source front face  111  surface area is flat. In a preferred embodiment of the invention, the LED optical source front face  111  surface area is circular. In an alternative embodiment of the invention, the LED optical source front face  111  surface area is square. In a preferred embodiment of the invention, the LED optical source back face  112  surface area is flat. In a preferred embodiment of the invention, the LED optical source back face  112  surface area is circular. In a preferred embodiment of the invention, the LED optical source back face  112  surface area is square. 
   Optical energy (i.e., photons) are created by a light emitting diode (“LED”) by the injection of electrical current into a semiconductor junction. The electrical current is injected by an electrical power source such as, but not limited to, an electrical wall plug, a battery, a fuel cell, a generator, etc. The selection of LED semiconductor material for the p and n type junctions determines the CCT range of the created optical energy emitted from the LED and dictates the amount of thermal energy produced by the LED as a result of the creation of optical energy from electrical energy. 
   In an alternative embodiment of the invention, LED optical source  110  can be any light source that produces optical energy. In an alternative embodiment of the invention, LED optical source  110  is an array of LEDs. In an alternative embodiment of the invention, LED optical source  110  is an array of nine LEDs placed in close proximity to each other. 
   In an alternative embodiment of the invention, electrical current is delivered to the LED semiconductor junction within the LED material  115  through a wire that connects a bond pad, which is positioned at the semiconductor junction on the LED, to electrically conducting gold posts, which pierce (or go through) a header. A header mounts or attaches the LED. In a preferred embodiment. the header attaches the LED to the heat dissipater  190 . The bond pad is the contact point for injecting electrical current into the semiconductor junction and the wire is an aluminum wire 0.0025 inches in diameter. The gold posts electrically attach to the electrical power source. 
   In an alternative embodiment, an electrically conducting material is positioned on the LED optical source back face  112 . In an alternative embodiment of the invention, the electrically conducting material is a gold plate positioned on the LED optical source back face  112 . In an alternative embodiment, the cathode (or negative polarity) is positioned on the LED optical source back face  112 . In an alternative embodiment, the anode (or positive polarity) is positioned on the LED optical source front face  111 . 
   In an alternative embodiment, an encapsulating layer is positioned on the LED optical source front face  111 . The encapsulate protects the aluminum wires from external forces that may cause the electrical connection to break. In an alternative embodiment, the encapsulate is Masterbond UV 15-7. 
   In a preferred embodiment of the invention, the index of refraction of the encapsulate is the same as the index of refraction of the phosphor layer  135 . In an alternative embodiment, the index of refraction of the encapsulate is greater than the index of refraction of the phosphor layer  135 . In a preferred embodiment of the invention, the index of refraction of the encapsulate is the same as the index of refraction of the concentrator  140 . In an alternative embodiment, the index of refraction of the encapsulate is greater than the index of refraction of the phosphor layer  135 . 
   In  FIG. 1 , electrical power is supplied to the LED optical source  110  by a power source. The power source is electrically attached to LED optical source  110 . In a preferred embodiment of the invention, the power source is a battery. In a preferred embodiment of the invention, the power source is an electrical wall socket. In a preferred embodiment of the invention, the power source is a fuel cell. 
   In  FIG. 1 , reflector  130  is a reflective optical element positioned to reflect optical energy emitted from the LED optical source back face  112  back into the LED optical source  110 . The reflector has a front face  131  that reflects optical energy and a back face  132  that attaches to thermal dissipater  190 . In a preferred embodiment of the invention, the reflector reflects optical energy back into the LED optical material  115  through the LED back face  112 . The optical energy then interacts with the optical material and a portion of the optical energy will exit LED front face  111  and interacts with the optical filter  120 . In a preferred embodiment of the invention, the reflector  130  is a mirror. In an alternative embodiment of the invention, reflector  130  filters out optical energy in the infrared spectrum. 
   In a preferred embodiment of the invention, the reflector  130  is an optical coating applied directly onto the LED optical source back face  112 . In a preferred embodiment of the invention, the reflector  130  is an optical coating applied directly onto the thermal dissipater  190 . In a preferred embodiment of the invention, the reflector  130  reflects optical energy at a CCT range of 6000K to 8000K. 
   In a preferred embodiment of the invention, the reflector front face  131  is flush with the LED optical source back face  112 . In a preferred embodiment, the reflector front face  131  surface area shape geometrically corresponds to the LED optical source back face  112  surface area shape. In an alternative embodiment of the invention, the reflector front face  131  surface area shape is larger than the LED optical source back face  112  surface area shape. In an alternative embodiment of the invention, the reflector front face  131  is smaller than the LED optical source back face  112  surface area shape. 
   In a preferred embodiment of the invention, the reflector front face  131  surface area is flat. In a preferred embodiment of the invention, the reflector back face  132  surface area is flat. In a preferred embodiment of the invention, the reflector front face  131  surface area shape is circular. In a preferred embodiment of the invention, the reflector back face  132  surface area is circular. 
   In  FIG. 1 , the optical filter  120  is positioned after LED optical source front face  111 . Optical filter  120  includes a front face  121  and a back face  122 . The optical energy emitted from LED optical source front face  111  enters optical filter back face  122  and interacts with optical filter  120 . The optical energy is then reflected back out optical filter back face  122  or transmitted through optical filter front face  121 , notwithstanding the slight amount of optical energy that is scattered and/or absorbed. 
   The optical filter  120  includes a reflected CCT range and a transmitted CCT range. Optical energy that is within the reflected CCT range is prohibited from passing through the optical filter  120  (e.g., via reflection). Optical energy that is within the transmitted CCT range passes through the optical filter  120 . In a preferred embodiment of the invention, the optical filter  120  transmits optical energy at a CCT range of 6000K to 8000K and reflects optical energy at a CCT range of 2500K to 6000K. 
   In a preferred embodiment of the invention, the optical filter front face  121  emits optical energy over a two pi steradian distribution. In a preferred embodiment of the invention, the optical filter back face  122  emits optical energy substantially over a two pi steradian distribution. 
   In a preferred embodiment of the invention, the optical energy spatial distribution emitted through optical filter front face  121  is uniform. In a preferred embodiment of the invention, the optical energy spatial distribution emitted through optical filter back face  122  is uniform. 
   In a preferred embodiment, the optical filter back face  122  is flush with the LED optical source front face  111 . A flush connection allows the optical filter back face  122  to capture two pi steradian angular distribution of optical energy from the LED optical source front face  111 . 
   In a preferred embodiment of the invention, the optical filter  120  is an optical coating. In an alternative embodiment of the invention, the optical filter  120  is a dielectric stack coated directly onto the LED optical source front face  111 . 
   In a preferred embodiment of the invention, the optical filter back face  122  surface area is flat. In a preferred embodiment of the invention, the optical filter back face  122  surface area is circular. In an alternative embodiment of the invention, the optical filter back face  122  surface area is square. In a preferred embodiment of the invention, the optical filter front face  121  surface area is flat. In a preferred embodiment of the invention, the optical filter front face  121  surface area is circular. In a preferred embodiment of the invention, the optical filter front face  121  surface area is square. 
   In a preferred embodiment, the optical filter back face  122  surface area shape geometrically corresponds to the LED optical source front face  111  surface area shape. A geometrically corresponding connection allows the optical filter back face  122  to interact with all of the optical energy being emitted from the LED optical source front face  111 . In an alternative embodiment of the invention, the optical filter back face  122  surface area shape is larger than the LED optical source front face  111  surface area shape. In an alternative embodiment of the invention, the optical filter back face  122  is smaller than the LED optical source front face  111  surface area shape. 
   In a preferred embodiment, the filter includes a stack of one fourth of the wavelength of light layers of alternating high and low refractive index to create the desired filtering characteristics. 
   In an alternative embodiment of the invention, the surface area shape of the optical Filter  120 , in reference to the concentrator  140 , is optimized to reflect particular CCT ranges. CRI values, and/or intensity values required in the first and/or second illumination regions. 
   In  FIG. 1 , the phosphor layer  135  is positioned to capture optical energy emitted from the optical filter front face  121 . The phosphor layer  135  includes a back face  137 , which receives optical energy from optical filter front face  121 , a front face  136 , which emits optical energy into said concentrator  140 , and sides  138 . 
   The phosphor layer  135  comprises material that when stimulated by optical energy of a particular CCT range (i.e., the stimulated CCT range), creates and emits new optical energy at a different CCT range (i.e., the phosphor-created CCT range) and, at the same time, allows non-stimulated optical energy (i.e., the non-stimulated CCT range) to transmit through the phosphor layer. In addition, the phosphor layer  135 , as an optical element, allows a certain percentage of optical energy of the stimulated CCT range (i.e., that is not absorbed by the phosphor) to transmit through the phosphor layer (i.e., due to scattering). 
   Phosphor layer characteristics, such as, but not limited to, the amount  of phosphor doping, the spectrum involved, and the thickness of the phosphor layer all affect the intensity and the wavelength spectrum that is emitted by the phosphor layer. The interaction of optical energy with the phosphor layer is an isotropic process resulting in an optical energy being emitted over a 4π distribution. Thus, optical energy emits out the phosphor layer back face,  137 , the front face  136 , and the sides  138 . 
   In a preferred embodiment, optical energy enters the phosphor layer back face  137  and the optical energy within the stimulated CCT range, stimulates the phosphor within the phosphor layer  135  creating new optical energy within a phosphor-created CCT range. The new optical energy within the phosphor-created CCT range, when combined with optical energy that enters the phosphor layer back face  137  that is in the non-stimulated CCT range provides optical energy that corresponds to white light. In a preferred embodiment of the invention, optical energy emits from phosphor layer front face  136  that corresponds to white light on the CCT range. 
   In an alternative embodiment of the invention, the phosphor layer characteristics are modified or adjusted to ensure optical energy of a specific CCT range emits from phosphor layer front face  136 . 
   A small percentage of optical energy is emitted out of the sides  138  of the phosphor layer (i.e., side loss). In a preferred embodiment of the invention, the amount of side loss is decreased by coating the interior side wall with a reflective material. In an alternative embodiment of the invention, the amount of side loss is decreased by reducing the surface area of the sides. In an alternative embodiment of the invention, side loss is reduced by placing the sides in contact with a medium of lower refractive index. 
   In a preferred embodiment of the invention, optical energy emitting from the phosphor layer back face  137  enters the optical filter  120  through the optical filter back face  122 . The optical filter  120  includes a reflected CCT range and a transmitted CCT range. Optical energy that is within the reflected CCT range is prohibited from passing through the optical filter  120  (e.g., via reflection). Optical energy that is within the transmitted CCT range passes through the optical filter  120 . Accordingly, the optical energy that enters the optical filter front face  121  from the phosphor layer back face  137  that is in the optical filter  120  reflected CCT range will be reflected back into the phosphor layer  135  and the optical energy that is in the optical filter  120  transmitted CCT range will transmit through the optical filter  120  and into the LED optical source  110 , but for losses associated with absorption and scattering. 
   In a preferred embodiment of the invention, the optical energy that enters the optical filter  120  from the phosphor layer  135  that is in the optical filter  120  transmitted CCT range transmits through the optical filter  120  and into the LED optical source  110  and then interacts with the optical reflective element  130 . At that point, the optical energy is reflected back into the LED material  115  and then transmits to the optical filter  120 . Since the optical energy is within the optical filter transmission wavelength spectrum, the optical energy passes through the filter and into the Phosphor Layer. whereupon the optical energy interacts with the phosphor layer thereby providing a repeating telescoping circular process for the optical energy that emits out of the phosphor layer back face  137 . This repeating process captures optical energy that would otherwise be lost. 
   In a preferred embodiment of the invention, the Phosphor layer  135  is Phosphor Technologies Yttrium Aluminum Oxide: Cerium QMK58/F-U1. In a preferred embodiment of the invention, the phosphor layer  135  is 0.254 millimeters thickness. In a preferred embodiment of the invention, the phosphor layer stimulated CCT range is 6000K to 8000K. In a preferred embodiment of the invention, the phosphor layer phosphor created CCT range is 2500K to 6000K. 
   In a preferred embodiment of the invention, the spatial distribution of the optical energy emitted through the phosphor layer front face  136  is uniform. In a preferred embodiment of the invention, the spatial distribution of the optical energy emitted through the phosphor layer back face  137  is uniform. 
   In a preferred embodiment, the phosphor layer back face  137  is flush with the optical filter front face  121 . In a preferred embodiment, the phosphor layer back face  137  surface area shape geometrically corresponds to the optical filter front face  121  surface area shape. In an alternative embodiment of the invention, the phosphor layer back face  137  surface area shape is larger than the optical filter front face  121  surface area shape. In an alternative embodiment of the invention, the phosphor layer back face  137  is smaller than the optical filter front face  121  surface area shape. 
   In a preferred embodiment of the invention, the phosphor layer front face  136  surface area is flat. In a preferred embodiment of the invention, the phosphor layer back face  137  surface area is flat. In a preferred embodiment of the invention, the phosphor layer front face  136  surface area shape is circular. In a preferred embodiment of the invention, the phosphor layer back face  137  surface area shape is circular. 
   In an alternative embodiment of the invention, the thickness of the phosphor layer is optimized to stimulate particular CCT ranges, CRI values, and/or optical energy values required in the first and/or second illumination regions. In an alternative embodiment of the invention, the surface area shape of the phosphor layer  135 , in reference to the concentrator  140 , is optimized to stimulate particular CCT ranges, CRI values, and/or optical energy values required in the first and/or second illumination regions. 
   In  FIG. 1 , the concentrator  140  is positioned to capture optical energy emitting out of the phosphor layer front face  136 . The concentrator  140  has an entrance aperture  142 , which receives optical energy from the phosphor layer front face  136 , and an exit aperture  141 , which outputs optical energy into the first illumination region  150 . The concentrator  140  captures optical energy up to a two pi steradian distribution via the entrance aperture  142 , aligns the optical energy via total internal reflection, and then outputs the aligned optical energy through the exit aperture  142  into a three dimensional symmetrical pattern or region, referred to as the first illumination region  150 . 
   In a preferred embodiment of the invention, the concentrator entrance aperture  142  is fully filled. In a preferred embodiment of the invention, the concentrator exit aperture  142  is fully filled. The entrance aperture is fully filled when entrance aperture receives optical energy over the entire entrance aperture. 
   In a preferred embodiment, the concentrator  140  is a non-imaging concentrator. A non-imaging concentrator provides a diverging illumination pattern. A concentrator provides a high degree of light collection. The theoretical throughput performance of a circular non-imaging concentrator is one hundred percent collection efficiency and close to ninety six percent of the collected optical energy exits through the exit aperture within the solid angle as defined by the concentrator physical characteristics. The approximate four percent loss is attributed to rim loss. A trough concentrator approaches 100% efficiency. The ideal profile of a non-imaging concentrator is a compound parabola, which is referred to as a compound parabolic concentrator (“CPC”). In a preferred embodiment of the invention, concentrator  140  is a CPC. In a preferred embodiment of the invention, the profile of concentrator  140  is determined by the angular illumination region requirements of the optical system. The reference Welford, Winston, “High Collection Nonimaging Optics”, Academic Press, Inc. &#39;89, ISBN 0-12-742885-2, which is hereby incorporated by reference, provides a detailed discussion of nonimaging optics. 
   Non-imaging concentrators maintain etundue. The etundue formula holds that the input numerical aperture multiplied by the input optical energy spatial extent equals the output numerical aperture multiplied by the output optical energy spatial extent. 
   In an alternative embodiment of the invention, the non-imaging concentrator has a profile constructed with a high order polynomial surface representing the attributes of the non-imaging concentrator form. In an alternative embodiment of the invention, the aspheric sag equation is tuned to match an appropriate non-imaging concentrator. In an alternative embodiment, the circumference of the concentrator is faceted. The higher the number of facets, the closer the faceted concentrator comes to producing the results of a circular concentrator. In a preferred embodiment of the invention, the concentrator emits optical energy with a CCT range of 4100K to 4900K. In a preferred embodiment of the invention, the concentrator emits optical energy that corresponds to white light according to the human visual system. In a preferred embodiment of the invention, the spatial distribution of the optical energy emitted through the non-imaging concentrator exit aperture  142  is uniform. 
   In a preferred embodiment of the invention, the concentrator entrance aperture  141  is flush with the phosphor layer front face  136 . In a preferred embodiment of the invention, the concentrator entrance aperture  142  surface area shape geometrically corresponds to the phosphor layer front face  136  surface area shape. In an alternative embodiment of the invention, the concentrator entrance aperture  142  surface area shape is larger than the phosphor layer front face  136  surface area shape. In an alternative embodiment of the invention, the concentrator entrance aperture  142  is smaller than the phosphor layer front face  136  surface area shape. 
   In a preferred embodiment of the invention, the index of refraction of the concentrator  140  is the same as the index of refraction of the phosphor layer  135 . In an alternative embodiment, the index of refraction of the concentrator  140  is less than the index of refraction of the phosphor layer  135 . 
   In a preferred embodiment of the invention, the concentrator entrance aperture  142  surface area is flat. In a preferred embodiment of the invention, the concentrator exit aperture  141  surface area is flat. In a preferred embodiment of the invention, the concentrator entrance aperture  142  surface area shape is circular. In a preferred embodiment of the invention, the concentrator exit aperture  141  surface area shape is circular. 
   In  FIG. 1 , the first illumination region  150  is positioned to receive optical energy emitted from the concentrator  140 . The optical energy that emits from the concentrator  140  has a corresponding angular distribution. This angular distribution of the optical energy forms diverging angles that define the first illumination region  150 . The first illumination region  150  has a first illumination region back face  152 , which defines the beginning area of the first illumination pattern, and a first illumination region front face  151 , which defines the end area of the first illumination pattern. In a preferred embodiment of the invention, the first illumination region  150  is a diverging conical three-dimensional region and is defined by the angular distribution characteristics associated with concentrator  140 . 
   The first illumination region  150  is located in a first illumination medium. In a preferred embodiment of the invention, the first medium is air. In a preferred embodiment of the invention, the first illumination medium does not require sides to bound or to direct the optical energy in the first illumination region since the optical energy in first illumination region is aligned. 
   In a preferred embodiment of the invention, the index of refraction of the first medium has a value of one. In a preferred embodiment of the invention, the index of refraction of the first medium is the same as the index of refraction of the concentrator  140 . In an alternative embodiment of the invention, the index of refraction of the first medium is less than the index of refraction of the concentrator  140 . In a preferred embodiment of the invention, the first illumination region  150  contains optical energy with a CCT range of 4100K to 4900K. In a preferred embodiment of the invention, the first illumination region front face  151  emits optical energy with a CCT range of 4100K to 4900K. In a preferred embodiment of the invention, the first illumination region contains optical energy that corresponds to white light according to the human Visual system. In a preferred embodiment of the invention, the first illumination region front face  151  emits optical energy that corresponds to white light according to the human visual system. In a preferred embodiment of the invention, the spatial distribution of the optical energy emitted through the first illumination region front face  152  is uniform. 
   In  FIG. 1 , the secondary optical element  160  is positioned to receive optical energy from the first illumination front face  151 . The secondary optical element  160  includes a back face  162 , which receives optical energy from the first illumination region  150  via first illumination front face  151 , and a front face  161 , which emits optical energy to a second illumination region  170 . 
   In a preferred embodiment of the invention, the secondary optical element  160  is a prism: and re-directs the aligned optical energy present in the first illumination region  150  to a second illumination region  170 . In a preferred embodiment of the invention, optical element  160  is positioned within the near field of the concentrator  140 . 
   In an alternative embodiment, secondary optical element  160  is any optical element that alters the optical energy present in the first illumination region  150 . Optical elements include, but are not limited to, a prism, lens, filter, concentrator, mirror, refractive element, diffractive element, wavelength modifier, intensity modifier, phosphorous layer, light pipe, etc. Optic energy can be altered according to, for example, but not limited to, spatial distribution, wavelength spectrum, intensity and angular distribution. 
   In a preferred embodiment of the invention, the secondary optical element back face  162  is flush with the first illumination region front face  151 . In a preferred embodiment of the invention, the secondary optical element back face  162  surface area shape geometrically corresponds to the first illumination region front face  151  surface area shape. In an alternative embodiment of the invention, the secondary optical element back face  162  surface area shape is larger than the first illumination region front face  151  surface area shape. In an alternative embodiment of the invention, secondary optical element back face  162  is smaller than the first illumination region front face  151  surface area shape. 
   In a preferred embodiment, the index of refraction of the secondary optical element  160  is the same as the index of refraction of the first medium. In an alternative embodiment, the index of retraction of the secondary optical element  160  is less than the index of refraction of the first medium. 
   In an alternative embodiment of the invention, the secondary optical element entrance aperture  162  is positioned to receive optical energy from the concentrator exit aperture  141 . The optical energy that enters the secondary optical element has an angular distribution as defined by the geometric shape of the concentrator. 
   In a preferred embodiment of the invention, the secondary optical element back face  162  is flush with the concentrator exit aperture  141 . In a preferred embodiment of the invention, the secondary optical element back face  162  surface area shape geometrically corresponds to the concentrator exit aperture  141  surface area shape. In an alternative embodiment of the invention, the secondary optical element back face  162  surface area shape is larger than the concentrator exit aperture  141  surface area shape. In an alternative embodiment of the invention, secondary optical element back face  162  is smaller than the concentrator exit aperture  141  surface area shape. 
   In a preferred embodiment, the index of refraction of the secondary optical element  160  is the same as the index of refraction of the concentrator  140 . In an alternative embodiment, the index of refraction of the secondary optical element  160  is less than the index of refraction of the concentrator  1140 . 
   In a preferred embodiment of the invention, the secondary optical element back face  162  surface area is flat. In a preferred embodiment of the invention, the secondary optical element front face  161  surface area is flat. 
   In a preferred embodiment of the invention, the secondary optical element back face  161  Surface area shape corresponds to the surface area of the interface between the illumination region and the secondary optical element back face  161 . In a preferred embodiment of the invention, the secondary optical element back face  162  surface area shape is circular. In a preferred embodiment of the invention, the secondary optical element front face  161  surface area shape is circular. In a preferred embodiment of the invention, the secondary optical element back face  162  surface area shape is oval. In a preferred embodiment of the invention, the secondary optical element front face  161  surface area shape is oval. 
   In an alternative embodiment of the invention, when the secondary optical element  160  is a reflector, optical energy reflects off of the secondary optical element back face  162  and is redirected into a different direction, such as, but not limited to, back into the concentrator  140 , back into the first illumination region  150 , into a second illumination region  170 , and/or into a second illumination region  170  that partially overlaps the first illumination region  150 . 
   In a preferred embodiment of the invention, the secondary optical element front face  161  emits optical energy with a CCT range of 4100K to 4900K. In a preferred embodiment of the invention, the secondary optical element back face  162  reflects optical energy with a CCT range of 4100K to 4900K. In a preferred embodiment of the invention, the secondary optical element front face  161  emits optical energy that corresponds to white light according to the human visual system. In a preferred embodiment of the invention, the secondary optical element back face  162  reflects optical energy that corresponds to white light according to the human visual system. In a preferred embodiment of the invention, the spatial distribution of the optical energy emitted from the secondary optical element front face  162  is uniform. 
   In  FIG. 1 , the second illumination region  170  is positioned to receive optical energy emitted (and/or reflected) from the secondary optical element  141 . The optical energy that emits (and/or reflects) from the secondary optical element  141  has a corresponding angular distribution. The angular distribution of the optical energy forms diverging angles that define the second illumination region  170 . The second illumination region  170  has a second illumination region back face  172 , which defines the beginning area of the second illumination pattern, and a second illumination region front face  171 , which defines the end area of the second illumination pattern and is also referred to as the target area. In an alternative embodiment, the second illumination pattern extends past the target area. In a preferred embodiment of the invention, the second illumination region  170  is a diverging conical three dimensional region and is defined by the angular distribution characteristics associated with secondary optical element  160 . 
   The second illumination region  170  is located in a second illumination medium. In a preferred embodiment of the invention, the second medium is air. In a preferred embodiment of the invention, the second illumination medium does not require sides to bound or to direct the optical energy in the second illumination region since the optical energy in second illumination region is aligned. 
   In a preferred embodiment of the invention, the index of refraction of the second medium has a value of one. In a preferred embodiment of the invention, the index of refraction of the second medium is the same as the index of refraction of the secondary optical element  160 . In an alternative embodiment of the invention, the index of refraction of the second medium is less than the index of refraction of the secondary optical element  160 . 
   In a preferred embodiment of the invention, the second illumination region  170  contains optical energy with a CCT range of 4100K to 4900K. In a preferred embodiment of the invention, the second illumination region front face  171  emits optical energy with a CCT range of 4100K to 4900K to a target  180 . In a preferred embodiment of the invention, the second illumination region contains optical energy that corresponds to white light according to the human visual system. In a preferred embodiment of the invention, the second illumination region front face  171  emits optical energy that corresponds to white light according to the human visual system to a target  180 . In a preferred embodiment of the invention, the spatial distribution of the optical energy emitted from the second illumination region front face  172  to a target  180  is uniform. 
   In a preferred embodiment of the invention, the second medium is flush with the secondary optical element front face  161 . In an alternative embodiment of the invention, the second medium is flush with the secondary optical element back face  162 . 
   In  FIG. 1 , the target  180  is positioned at the second illumination region front face  171 . Optical energy present at the second illumination front face  171  interacts with the target  180  and reflects to the human visual system. In an alternative embodiment of the invention, the target  180  is located within the second illumination region  170 . 
   In  FIG. 1 , the thermal dissipater  190  is thermally attached to the LED optical source  110 . The thermal dissipater  190  dissipates thermal energy present in the white light system  100 . In an alternative embodiment of the invention, the thermal dissipater  190  is thermally attached at any place in the white light system  100 , including, but not limited to the LED optical source  110 , the power source, the optical reflector  130 , the optical filter  120 , the phosphor layer  135 , the concentrator  140 , the first illumination region  150 , the first medium, the secondary optical element  160 , the second illumination region  170 , the second medium, and/or the target  180 , etc. 
   Thermal energy results from the creation of photons from electricity. In addition, optical energy within the infrared spectrum provides thermal energy. Infrared radiation has longer wavelengths than the visible spectrum and is sensed as thermal energy or heat. 
   In an alternative embodiment of the invention, an intercepting optical element, such as, but not limited to, a filter, a reflector, or absorber, etc., is positioned within white light system  100  to intercept optical energy in the infrared system. The thermal dissipater  190  is then thermally attached to this intercepting optical element. 
   In a preferred embodiment, the heat dissipater  190  is a heat sink. In an alternative embodiment of the invention, a header (not shown) is used to mount or attach the LED optical source  110  to the heat dissipater  190 . In an alternative embodiment of the invention, the header is thermally conductive, thereby allowing thermal energy present in the LED optical source to transfer to the heat dissipater  190 . 
   In an alternative embodiment, the header is electrically conductive, thereby providing an electrical connection for electrical power to reach the LED optical source  110 . In an alternative embodiment of the invention, the header material includes copper. In an alternative embodiment of the invention, the header is formed into a thin cylinder. 
   In an alternative embodiment, the heat dissipater includes fins. The fins increase the surface area of the heat dissipater, which increases thermal dissipation. 
   In an alternative embodiment of the invention, a heat spreader is positioned between the heat sink and the LED optical source  110 . The heat spreader is thermally attached to the LED optical source  110  and pulls the thermal energy away from the thermal energy source and disburses the thermal energy laterally (i.e., the LED optical source  110 ). Increased thermal dissipation provides for increased electric efficiency within the LED. In an alternative embodiment of the invention, the heat spreader material includes diamond. Diamond has a high thermal conductivity and thus permit higher operating currents to be used without increasing the temperature of the LED. In an alternative embodiment of the invention, the heat spreader material includes any material with a high conductivity, such as, but not limited to copper, aluminum, etc. The heat spreader is thermally attached to the thermal dissipater  190  and/or the heat sink. 
     FIG. 2  illustrates a flow diagram of the white light system according to a preferred embodiment of the invention. Referring to the elements illustrated in  FIG. 1 , in the first step. (step  205 ) a light source provides optical energy at a particular spectrum. In a preferred embodiment of the invention, the light source is an LED optical source  110 , which creates photons when a current field is applied across the LED semiconductor junction. In a preferred embodiment of the invention, the created photons have a 4π steradian angular distribution. In a preferred embodiment of the invention, the electric power is provided to the LED optical source by a power source. The thermal energy produced by the LED optical source is dissipated by a thermal dissipater  190 . In a preferred embodiment of the invention, the thermal dissipater is a heat sink, which dissipates the heat. In an alternative embodiment of the invention, a header (not shown) is used to attach the heat sink to the LED optical source. In an alternative embodiment of the invention, a heat spreader (not shown) is used to distribute the thermal energy from the LED optical source to the heat sink. In a preferred embodiment of the invention. the white light system  100  merges the optical energy created by the LED optical source and the optical energy created by the phosphor layer  135  to produce white light. 
   In the next step, (step  210 ) the photons interact within the LED semiconductor junction. The photons within the semiconductor junction emit in the direction of the LED optical source back face  112  and in the direction of the LED optical source front face  111 . There is some loss due to optical scattering and absorption. 
   It is next determined (step  215 ) whether the photons in the LED are traveling toward the LED optical source back face  112 . The photons that reach the LED optical source back face  112  interact with a reflector  130  (step  220 ) and the photons that are within the reflected spectrum are reflected back into the LED optical source  110  (step  210 ). Since the reflected optical energy is traveling in a direction towards the LED optical source front face  111 , the reflected optical energy has a high probability of reaching the LED optical source front face  111 . Thus, the optical efficiency of the white light system  100  is improved by the addition of a reflector to capture otherwise lost optical energy. In an alternative embodiment of the invention, the reflected spectral width is tailored to optimize the production of white light by the white light system  100 . 
   The photons that reach the LED optical source front face  111  interact with an optical filter  120  (step  225 ). The optical filter  120  has a reflected spectral width and a transmitted spectral width. The optical energy that is within the reflected spectral width is reflected out of the face the optical energy interfaced the filter. The optical energy that is within the transmitted spectral width is transmitted through the optical filter. In a preferred embodiment of the invention, the optical filter  120  is coated directly onto the LED front face  111 . In an alternative embodiment of the invention, the reflected spectral width and the transmitted spectral width is tailored to optimize the production of white light by the white light system  100 . 
   It is next determined if the optical energy interacting with the optical filter  120  is within the transmitted spectrum (step  230 ). If the optical energy is not within the transmitted spectrum, it is next determined from what direction the optical energy came from (step  235 ). If the optical energy that is not in the transmitted spectrum entered (or interfaced with) the optical filter back face  122 , then the optical energy is reflected back into the LED optical source  110  (step  210 ). In the example, since the LED does not provide optical energy within the optical filter spectrum, very little optical energy will be reflected according to this particular step, but for that associated with scattering. However, if it is determined (see step  235 ) the optical energy, that is not in the optical filter transmitted spectrum, entered (or interfaced with) the optical filter front face  122 , then the optical energy reflects back into the phosphor layer  135  to interact with the phosphor layer (step  245 ). 
   On the other hand, if it is determined (see step  230 ) that the optical energy interacting with the optical filter  120  is within the transmitted spectrum, then it must next be determined what direction the optical energy came from (step  240 ). If the optical energy that is within the transmitted spectrum entered (or interfaced with) the optical filter back face  122 , then the optical energy transmits through the optical filter  120  and into the phosphor layer  135  to interact with the phosphor layer (step  245 ). However, if the optical energy that is within the transmitted spectrum entered (or interfaced with) the optical filter front face  121 , then the optical energy transmits through the optical filter  120  and into the LED optical source  110  (step  210 ) 
   Next, it is determined if the optical energy that enters (or interacts with) the phosphor layer is within the stimulated spectral width (step  250 ). The optical energy that interacts with the phosphor layer  135  that is not within the stimulated spectral width passes through the phosphor layer and exits the phosphor layer through the phosphor layer front face  136  (step  255 ) 
   For the optical energy that enters (or interacts with) the phosphor layer  135  that is within the stimulated spectral width, it is next determined if the optical energy is absorbed by the phosphor (step  260 ). If the optical energy that enters (or interacts with) the phosphor layer  135  and is within the stimulated spectral width is not absorbed by the phosphor, the optical energy transmits through the phosphor layer  135  and exits the phosphor layer through the phosphor layer front face  136  (step  265 ). 
   If the optical energy that enters (or interacts with) the phosphor layer  135  and is within the stimulated spectral width is absorbed by the phosphor, then new optical energy is created (step  270 ) (i.e., phosphor created optical energy). The phosphor created optical energy is at a spectral width that is different than the optical energy that was absorbed by the phosphor. In addition. the phosphor created optical energy has a 4π steradian angular distribution. Accordingly, the phosphor created optical energy emits out of the phosphor layer front face  136  and the phosphor layer back face  137 . The amount of absorption is determined by, for example, but not limited to. the amount of phosphor doping, the thickness of the phosphor layer, the concentration of the phosphor particles within the suspension medium, etc. In a preferred embodiment of the invention, the amount of absorption is regulated to optimize a desired CCT range. CRI value, and/or optical energy produced by the white light system  100 . 
   For the phosphor created optical energy, it is next determined if the optical energy emits out the phosphor layer front face  136  (step  275 ). If the phosphor created optical energy emits out the phosphor layer front face  136 , then the optical energy passes through to the concentrator entrance aperture  142  (Step  280 ). If the phosphor created optical energy emits out the phosphor layer back face  137 , then the optical energy transmits to the optical filter front face  121  (Step  285 ) and interacts with the optical filter (i.e., reflect or transmit) (step  225 ). 
   There are three aforementioned paths that optical energy exits phosphor layer front face  136 , namely, from optical energy outside the stimulated range (see step  255 ), from non-absorbing optical energy within the stimulated range (see step  265 ), and phosphor created optical energy (see step  280 ) and enters the concentrator entrance aperture  142 . In a preferred embodiment of the invention, the combination of the optical energy originating from these three paths, when properly mixed within the concentrator  140 , produce white light. In addition, in an alternative embodiment of the invention, the contribution of optical energy from each path is modified to optimize a desired CCT range, CRI value, and/or optical energy produced by the white light system  100 . 
   The concentrator  140  aligns and outputs the optical energy captured by way of the aforementioned three paths (step  290 ). In addition, the concentrator  140  mixes the optical energy captured at the concentrator entrance aperture  142  in so that the optical energy emitted by the concentrator exit aperture  141  is spatially uniform. The nature of the non-imaging concentrator is to transfer optical energy from one point to another and from one angular region to another. The non-imaging aspects of the concentrator provide mixing of the spatial distribution of the optical energy at the entrance aperture  142  such that the spatial distribution at the exit aperture  141  is uniform. 
   The emitted optical energy from the concentrator exit aperture  142 , if left unobstructed, forms a diverging conical shaped first illumination region (step  292 ). The optical energy in the first illumination pattern then interacts with a secondary optical element  160 , which modifies the optical energy in the first illumination pattern (step  294 ) to form a second illumination pattern (step  296 ). 
   EXAMPLE 
   Referring to  FIG. 1 , in a preferred embodiment of the invention, the LED optical source  110  is a combination of two LED optical sources. The first LED optical source  110  is an array of eight CREE Xbright Power Chip LED C470-XB900, which requires 1,125 milliwatts of electric power (i.e., 350 milliamps at 3.5 volts) to produce 150 milliwatts of optical power from each LED for optical energy with a spectral width of 440 nanometers to 480 nanometers and a spectral peak at 460 nanometers. The total optical power for the first LED optical source is therefore 1,350 milliwatts. The first LED optical source represents the stimulated optical energy. The second LED optical source  110  is one Lumileds HWFR-B515, which requires 700 milliwatts of electric power (i.e. 250 milliamps at 2.8 volts) to produce 150 milliwatts of optical power from the LED for optical energy with a spectral width of 620 nanometers to 660 nanometers and a spectral peak at 640 nanometers. The second LED optical source represents the non-stimulated optical energy. The total optical power for the combination of the First and second LED optical sources is therefore 1,500 milliwatts. The optical energy emits a two pi steradian angular distribution at the LED optical source front face  111  and the LED optical source back face  112 . A reflector  130  is placed at the LED optical source back face  112  to reflect the two pi steradian angular distribution back into the LED and out through the LED optical source front face  111 , minus any loss due to scattering and absorption, etc., thereby increasing the optical energy. The reflector has a reflected spectral width of 380 nanometers to 750 nanometers. 
   In a preferred embodiment of the invention, the optical filter  120  is coated on the LED optical source front face and the optical filter reflects optical energy between 500 nanometers to 750 nanometers and transmits optical energy between 380 nanometers and 500 nanometers. In a preferred embodiment of the invention, the optical filter reflects and transmits optical energy according to the a particular reflected spectrum width and a particular transmitted spectral width from both the optical filter front face  121  and the optical filter back face  122 . In other words the filtering characteristics for the optical filter  120  are the same, independent on what direction the optical energy enters (or interacts with) the filter. In the example, since the LED provides optical energy between 440 nanometers and 480 nanometers, the LED optical source  110  created optical energy will pass through the optical filter back face  122  and into phosphor layer  135  unencumbered, but for nominal absorption and scattering losses. 
   In a preferred embodiment of the invention, the phosphor layer  135  is a mixture of phosphor and UV curable epoxy. The phosphor is Phosphor Technologies CS:YAG and the UV curable epoxy is Masterbond UTV 15-7. The phosphor layer  135  is 0.254 millimeters thick and has a phosphor doping population of one part phosphor in twenty parts epoxy by weight. In the continuing example, the phosphor layer has a stimulated spectral peak of 470 nanometers, a non-stimulated spectral peak of 640 nanometers and when stimulated, produces optical energy over a 4 pi steradian angular distribution with a spectral width of 500 nanometers to 750 nanometers, with a spectral peak of 550 nanometers and emits out of the phosphor layer back face  137  and the phosphor layer front face  136 . 
   The optical energy created by the phosphor layer  135  that is emitted out of the phosphor layer back face  137  (i.e., within spectral width 500 nanometers to 750 nanometers) reflects off of the optical filter front face  121  (i.e., since the optical energy is within the reflected spectrum of the optical filter) and then interacts with the phosphor layer  135 . Since the reflected optical energy is within the spectral width of 500 nanometers to 750 nanometers, the optical energy transmits through the phosphor layer  135  and exits through the phosphor layer front face  136 , but for optical energy lost due to absorption and scattering. In a preferred embodiment of the invention, Side loss, within the phosphor layer  135 , is reduced by coating the side walls with reflective material. 
   In the example, a small proportion of optical energy will exit the phosphor layer back face  137  within the spectral width of 380 nanometers to 500 nanometers due to scattering during the interaction with the phosphor layer  135 . However, this energy is ultimately redirected by the white light system  100 . Specifically, this optical energy (i.e., within spectral width 380 nanometers to 500 nanometers) transmits through the optical filter  130  (i.e., enters the optical filter front face  121 , transmits through the filter, and exits through the optical filter back face  122 ), enters the LED optical source  110 , and then reflects off of the reflector  130  (since the reflector  1  A has a reflected spectrum of 380 nanometers to 750 nanometers). The reflected optical energy then travels back through the LED optical source  110 , through the optical filter  130 , and then interacts with the phosphor layer  135 . This telescoping circular path for the optical energy contributes to the optical power (intensity), the CCT range, and the CRI value associated with the optical energy emitting out of the phosphor layer front face  136  at each revolution. 
   In addition, a partial amount optical energy within the phosphor layer stimulated spectral width will not be absorbed by the phosphor layer and pass through the phosphor layer and exit at the phosphor layer front face  136 . The five paths of optical energy, the revolving path, the stimulated and absorbed path, the stimulated but not absorbed path, the non stimulated path, and the optical filter reflected path all contribute to the optical energy, the CCT range, and the CRI value associated with the optical energy emitting out of the phosphor layer front face  136 . 
   The phosphor layer emits 450 milliwatts of optical energy with a two pi steradian distribution out the phosphor layer front face  136  with a spectral width of 440 nanometers to 730 nanometers with a primary peak at 460 and 640 nanometers (i.e., primarily from the LED created optical energy) and a secondary peak at 550 nanometers (i.e., primarily from the phosphor layer created optical energy), which produces a CCT (7300K) of 4200K and a CRI value of 92, which corresponds to white light. 
   Then, the concentrator entrance aperture  142  captures the two pi steradian optical energy emitting from the phosphor layer front face  136 , mixes and aligns the optical energy, and then emits 432 milliwatts of spatially uniform white light with a CCT of 4200K and a CRI value of 92, into a diverging first illumination region  150 . 
   The optical energy in the first illumination pattern then interacts with a secondary optical element  160 . which modifies the optical energy in the first illumination region (step  294 ) to form a second illumination region (step  296 ). In a preferred embodiment of the invention, the second illumination region contains a target  180 , which is illuminated with optical energy present in the second illumination region  170 . 
     FIG. 3  illustrates a LED curing system  300  according to a preferred embodiment of the invention for curing, bonding, and/or sealing light sensitive targets. The LED curing system  300  includes a LED optical source  310 , a heat spreader  320 , a heat sink  330 , a concentrator  340 , a light guide  350 , power source  360 , electronic controls  370 , and a cycle controller  380 , an illumination region  390 , and a target  395 . 
   LED optical source  310  is optically coupled to concentrator  340 . LED optical source  310  includes a LED, which emits optical energy over a 4π steradian angular distribution, at a particular CCT range, at a particular wavelength spectrum and at a particular intensity. The CCT range includes the visible light spectrum, the ultraviolet light spectrum and the infrared light spectrum. 
   In an alternative embodiment, the LED optical source  310  includes a back reflector to capture additional optical energy and direct the optical energy to the concentrator  340 . In an alternative embodiment of the invention, the LED optical source includes an array of LED&#39;s. In a preferred embodiment of the invention, optical requirements of the illumination region  390  determine the type, quantity and location of the LED&#39;s within the array that are located within the LED optical source  310 . 
   In an alternative embodiment of the invention, the LED optical source  310  includes an array of LED&#39;s, which are positioned in an optimal location to increase thermal dissipation. In an alternative embodiment of the invention, the LED optical source  310  includes an array of LED&#39;s, which are positioned in an optimal location to obtain a desired CCT range in the illumination region  390 . In an alternative embodiment of the invention, LED optical source  310  emits optical energy that matches the absorption CCT range of a particular light curing material. 
   In an alternative embodiment of the invention, the LED optical source  310  is optimized to satisfy particular thermal energy requirements of the LED curing system  300 . Many curing systems are utilized in medical environments, which are sensitive to thermal energy (i.e., increase temperature). 
   The heat spreader  320  is thermally attached to the LED optical source  310  and pulls the thermal energy away from the thermal energy source (i.e., the LED optical source  310 ). Increased thermal dissipation provides for increased electric efficiency within the LED. In a preferred embodiment of the invention, the heat spreader  320  material includes diamond. Diamond has a high thermal conductivity and thus permit higher operating currents to be used without increasing the temperature of the LED. In an alternative embodiment of the invention, the heat spreader  320  material includes any material with a high conductivity, such as, but not limited to copper, aluminum, etc. The heat spreader  320  is thermally attached to the heat sink  330 . 
   The heat sink  330  is thermally attached to the heat spreader. In an alternative embodiment, the heat sink  330  acts a casing for the LED curing system  330 . In an alternative embodiment. the heat sink  330  acts as a light guide to guide optical energy present in the illumination region  390 . 
   In an alternative embodiment, the heat sink  330  provides an integrating anchor for the light guide  350 . In an alternative embodiment, the heat sink  330  is cooled by water to effectuate the dissipation of thermal energy. In an alternative embodiment, the heat sink  330  uses conductive cooling to dissipate thermal energy. In an alternative embodiment of the invention. the size, shape, and material of the heat sink is optimized to maximize the amount of thermal energy that the heat sink  330  dissipates. 
   The concentrator  340  is positioned to capture optical energy emitted from the LED optical source  310  and includes an entrance aperture and an exit aperture. Optical energy is received from the LED optical source  310  via the concentrator entrance aperture. The concentrator then aligns the received optical energy and then outputs the optical energy through the concentrator exit aperture to the light guide  350 . 
   In a preferred embodiment of the invention, the concentrator  340  is a non-imaging concentrator. In a preferred embodiment of the invention, the concentrator  340  is a CPC shaped concentrator. In a preferred embodiment of the invention, the concentrator is flush with the LED optical source  310 . In a preferred embodiment of the invention, the concentrator  340  includes a reflective coating on the inside surface to provide for an optically efficient transfer of optical energy from concentrator entrance aperture to the concentrator exit aperture. In a preferred embodiment of the invention, the concentrator  340  includes a dielectric material to provide for an optically efficient transfer of optical energy from concentrator entrance aperture to the concentrator exit aperture. In a preferred embodiment of the invention, any area between the LED light source  310  and the concentrator  340  is filled with an optically clear cement or gel to match the refractive index (e.g., when the concentrator is filled with a dielectric material.). 
   In a preferred embodiment of the invention, the concentrator is made of a dielectric material. In a preferred embodiment of the invention, the concentrator is made of a dielectric material that has a sufficient index of refraction to permit total internal reflection. In a preferred embodiment of the invention, the concentrator is made of a hollow reflector. In a preferred embodiment of the invention, the concentrator is made of a dielectric material. 
   The light guide  350  is positioned to receive aligned optical energy from the exit aperture of the concentrator  340 . The light guide has an entrance aperture, which receives optical energy from the concentrator  340 , and an exit aperture, which emits optical energy into an illumination region  390 . In a preferred embodiment of the invention, the light guide  350  delivers the optical energy to an illumination region. 
   The power source  360  is electrically attached to the LED optical source  310  and provides electricity to the LED optical source  310 . In a preferred embodiment of the invention, the power source  360  is a battery. In a preferred embodiment of the invention, the power source  360  is a hand held battery. In a preferred embodiment of the invention, the power source  360  is a battery that transfers 3,500 milliwatts of electrical power to the LED optical source. In a preferred embodiment of the invention, the power source  360  is positioned in the base of the LED curing system  300 . To satisfy the curing application requirements, such as, but not limited to, CCT range intensity requirements, continuous use, etc., conventional systems use brute force (i.e., large optical sources, that emit large amounts of heat and require large amounts of power) since the conventional systems have poor electrical and optical efficiency. Thus, conventional systems cannot satisfy application requirements using a hand-sized off the shelf battery. In a preferred embodiment of the invention, the power source  360  is a rechargeable battery. In a preferred embodiment of the invention, the power source  360  is a wall plug. 
   The electronic controls  370  provide a user with control over the duration, the intensity and the CCT range of the optical energy emitted from the LED curing system  300  onto the target  395 . In a preferred embodiment of the invention, the electronic controls can cycle on and off particular LED&#39;s within the LED optical source. In a preferred embodiment of the invention, the electronic controls can increase or decrease the electrical current to the LED optical source  310 . In a preferred embodiment of the invention, the electronic controls can increase or decrease the electrical current to a particular LED within the LED optical source  310 . 
   In a preferred embodiment of the invention, the electronic controls provide pulsing of the LED optical source  310  for a prescribed duty cycle. In a preferred embodiment of the invention, the electronic controls provide pulsing of the LED optical source  310  for a prescribed pulse duration. In a preferred embodiment of the invention, the electronic controls provide pulse width modulation (“PWM”) of the LED optical source  310 . PWM provides a constant drain on the power source as a function of the power source lifetime, which results in a constant output electrical power to the LED optical source  310  over the entire power source life cycle. 
   The cycle controller  380  is electrically attached to the power supply. Engaging the cycle controller  380  allows a user to initiate the LED curing system for one cycle. In a preferred embodiment of the invention, a cycle is ten seconds on and ten seconds off. 
   The illumination region is optically coupled to the light pipe  350 . The illumination region begins at the exit aperture of the light pipe and continues in a diverging region. In a preferred embodiment of the invention, the optical power emitting at the exit aperture of the light pipe  350  is approximately ten to eighteen percent of the input electrical power. 
   The target  395  is positioned within the illumination region  390 . In a preferred embodiment of the invention, the target  395  is positioned within the near field of the illumination region  390 . In a preferred embodiment of the invention, the target includes a light sensitive material that cures when exposed to the optical energy within the illumination region  390 . 
   In a preferred embodiment of the invention, the target includes a sealant that cures when introduced to the optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes an adhesive that cures when introduced to the optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes a composite that cures when introduced to the optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes light curing sealants used in lung surgery that cures when introduced to the optical energy within the illumination region  390 . 
   In a preferred embodiment of the invention, the target includes light curing sealants used in dentistry when introduced to the optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes a composite used in dentistry that cures when introduced to the optical energy within the illumination region  390 . 
   In a preferred embodiment of the invention, the target includes a light sensitive material for bonding that bonds when introduced to the optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes a light sensitive material for sealing that seals when introduced to the optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes a light sensitive material for bonding that bonds dental fixtures and/or dental implants when introduced to the optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes a light sensitive material for sealing that seals dental fixtures and/or dental implants when introduced to the optical energy within the illumination region  390 . Light sensitive materials are used for bonding and/or sealing. For instance, the dental market has chosen light sensitive adhesives for bonding and sealing of dental fixtures and other dental implants. 
   In a preferred embodiment of the invention, the target includes adhesives that cure when introduced to ultra-violet optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes adhesive used in industrial applications that cures when introduced to ultra-violet optical energy within the illumination region  390  In a preferred embodiment of the invention, the target includes a biocompatible material that cures when introduced to the optical energy within the illumination region  390 . In a prefer-red embodiment of the invention, the target includes a biocompatible material located topically that cures when introduced to the optical energy within the illumination region  390 . In a preferred embodiment of the invention, the target includes a biocompatible material located within a body cavity that cures when introduced to the optical energy within the illumination region  390 . 
   In an alternative embodiment of the LED curing system  300 , the LED curing system  300  is portable. In an alternative embodiment of the LED curing system  300 . the LED curing system  300  weighs 90 grams. In an alternative embodiment of the LED curing system  300 . the LED curing system  300  has dimensions of 146 millimeters long by 18 millimeters diameter. In an alternative embodiment of the LED curing system  300 , the LED curing system  300  is disposable. 
     FIG. 4  illustrates a LED photo dynamic therapy system  400  according to a preferred embodiment of the invention. The LED photo dynamic therapy (“PDT”) curing system  400  includes a LED optical source  410 , a heat spreader  420 , a heat sink  430 , a concentrator  440 , power Source (not shown), an illumination region  460 , a therapeutic region  470  and a target (not shown ). 
   LED optical source  410  is optically coupled to concentrator  440 . LED optical source  410  includes a LED, which emits optical energy over a 4π steradian angular distribution at a particular CCT range, a particular wavelength spectrum, and at a particular intensity. The CCT range includes the visible light spectrum, the ultraviolet light spectrum and the infrared light spectrum. 
   In an alternative embodiment, the LED optical source  410  includes a back reflector to capture additional optical energy and direct the optical energy to the concentrator  440 . In an alternative embodiment of the invention, the LED optical source  410  includes an array of LEDs. In an alternative embodiment of the invention, optical requirements of the illumination region  460  determine the type, quantity and location of the LED that is located within the LED optical source  410 . 
   In an alternative embodiment of the invention, the LED optical source  410  includes an array of LEDs, which are positioned in an optimal location to increase thermal dissipation. In an alternative embodiment of the invention, the LED optical source  410  includes an array of LEDs, which are positioned in an optimal location to obtain a desired wavelength spectrum in the illumination region  460 . In an alternative embodiment of the invention, the LED optical source  410  includes an array of LEDs, which are positioned in an optimal location to obtain a desired wavelength spectrum in the illumination region  390 . 
   In a preferred embodiment of the invention, the wavelength spectrum of the optical energy in the illumination region  460  is absorbed by a photosensitizer or drug compound. PDT involves injecting or doping biomaterial, such as, but not limited to, blood, cells, tissue, etc. with a photosensitizer or drug compound. Photosentizers and drug compounds, atoms, molecules, etc., responds to particular wavelengths of optical energy. When the photosensitizer or drug compound is exposed to a particular wavelength of optical energy, it absorbs the optical energy and emits a singlet oxygen or undergoes some other photochemical reaction. The singlet oxygen oxidizes critical elements of neoplastic cells (i.e., of the tumor cells). Thus, the wavelength spectrum of the optical energy within the illumination region  460  is determined by what wavelength will alter the photosensitizer (and, ultimately, the cell) or drug compound. 
   In a preferred embodiment of the invention, the wavelength spectrum of the optical energy in the illumination region  460  penetrates tissue located in the target  480 . Optical energy with longer wavelengths penetrate tissue deeper than optical energy with shorter wavelengths. Thus, for example, the photosensitizer porfimer sodium has a peak absorption in the area of 405 nanometers (blue-violet) and another peak absorption in the area of 630 nanometers (red). Since red has a longer wavelength than blue-violet, the red optical energy will penetrate the tissue deeper than the blue-violet optical energy. Thus, the LED PDT system uses a LED optical system that produces optical energy with a peak at 630 nanometers. 
   In an alternative embodiment of the invention, LED optical source  410  emits optical energy that matches the absorption peak of a particular PDT photosensitizer. In an alternative embodiment of the invention, the optical energy produced by the LED PDT system corresponds to the absorption peak with the longest wavelength. 
   In an alternative embodiment of the invention, the LED optical source  410  is optimized to satisfy particular thermal energy requirements of the LED curing system  300 . Many curing systems are utilized in medical environments, which are sensitive to thermal energy (i.e., increase temperature). 
   In an alternative embodiment of the invention, the LED is bonded to the heat spreader  420  with a thermally conductive material. In an alternative embodiment of the invention. the LED is soldered to the head spreader  420 . In an alternative embodiment of the invention. the LED is bonded to the heat sink  430  with a thermally conductive material. In an alternative embodiment of the invention, the LED is soldered to the head sink  430 . 
   The heat spreader  420  is thermally attached to the LED optical source  410  and pulls the thermal energy away from the thermal energy source (i.e., the LED optical source  410 ). Increased, thermal dissipation provides for increased electrical efficiency within the LED. In a preferred embodiment of the invention, the heat spreader  410  material includes diamond. Diamond has a high thermal conductivity and thus permits higher operating electrical currents to be used without increasing the temperature of the LED. In an alternative embodiment of the invention, the heat spreader  420  material includes any material with a high conductivity, such as, but not limited to copper, aluminum, etc. The heat spreader  420  is thermally attached to the heat sinks  430 . 
   The heat sink  430  is thermally attached to the heat spreader  420 . In an alternative embodiment of the invention, the heat sink  430  acts as a casing for the LED PDT system  400 . In an alternative embodiment, the heat sink  430  acts as a light guide to guide optical energy present in the illumination region  460 . 
   In an alternative embodiment of the invention, the heat sink  430  is cooled by water to effectuate the dissipation of thermal energy. In an alternative embodiment, the heat sink  430  uses conductive cooling to dissipate thermal energy. In an alternative embodiment of the invention, the size, shape, and material of the heat sink is optimized to maximize the amount of thermal energy that the heat sink  430  dissipates. 
   The concentrator  440  is positioned to capture optical energy emitted from the LED optical source  410  and includes an entrance aperture and an exit aperture. Optical energy is received from the LED optical source  410  via the entrance aperture of the concentrator  440 . The concentrator  440  then aligns the received optical energy and then outputs the optical energy through the exit aperture of the concentrator  440  to the illumination region  460 . 
   In a preferred embodiment of the invention, the concentrator  440  is a non-imaging concentrator. In a preferred embodiment of the invention, the concentrator  440  is a compound parabolic concentrator (“CPC”) shaped concentrator. In a preferred embodiment of the invention, the concentrator is flush with the LED optical source  410 . In a preferred embodiment of the invention. the concentrator  440  includes a reflective coating on the inside surface to provide for an optically efficient transfer of optical energy from entrance aperture of the concentrator to the exit aperture of the concentrator. In a preferred embodiment of the invention, the concentrator transfers optical energy from the entrance aperture of the concentrator  440  to the exit aperture of the concentrator  440 . In a preferred embodiment of the invention, any area between the LED optical source  410  and the concentrator  440  is filled with an optically clear cement or gel to match the refractive index (e.g., when the concentrator is filled with a dielectric material.). 
   In a preferred embodiment of the invention, the concentrator is made of a dielectric material. In a preferred embodiment of the invention, the concentrator is made of a dielectric material that has a sufficient index of refraction to permit total internal reflection. In a preferred embodiment of the invention, the concentrator is made of a hollow reflector. In a preferred embodiment of the invention, the concentrator is made of a dielectric material. 
   The power source (not shown) is electrically attached to the LED optical source  410  and provides electricity to the LED optical source  410 . In a preferred embodiment of the invention. the power source is a battery. In a preferred embodiment of the invention, the power source is a hand held battery. In a preferred embodiment of the invention, the power source is a battery that transfers 600 watts of electrical power to the LED optical source. In a preferred embodiment of the invention, the power source is a rechargeable battery. In a preferred embodiment of the invention, the power source is a wall plug. 
   The illumination region is optically coupled to the exit aperture of the concentrator  440 . The illumination region begins at the exit aperture of the concentrator and continues in a diverging region. In a preferred embodiment of the invention, the optical power emitting at the exit aperture of the light pipe  350  is approximately ten to eighteen percent of the input electrical power. 
   The therapeutic area is provided by an LED PDT system with multiple LED optical sources each with a dedicated concentrator, and each providing a unique illumination region. Each individual subsystem is referred to as a PDT light engine. In an alternative embodiment of the invention, the multiple illumination regions partially overlap. 
   The target (not shown) is positioned within the illumination region  460 . The target is positioned within the therapeutic area  470 . In a preferred embodiment of the invention, the target is positioned within the near field of the illumination region  460 . In a preferred embodiment of the invention, the target is positioned within the far field of the illumination region  460 . 
   In a preferred embodiment of the invention, the target includes a photosensitiser that undergoes a photochemical reaction when introduced to the optical energy in the therapeutic area  470 . In a preferred embodiment of the invention, the target includes a drug compound that undergoes a photochemical reaction when introduced to the optical energy in the therapeutic area  470 . 
     FIG. 5  illustrates a multi-wavelength LED array illumination system  500  according to an alternative embodiment of the invention. The multi-wavelength LED array illumination system  500  includes a LED array  510 , a heat sink  520 , a ceramic board  530 , an array of concentrators  540 , a light integrator  550  having an entrance facet  552  and an exit facet  554 , and an illumination region  560  and a target  570 . 
   The LED array  510  comprises LED groups  512 . Each LED group comprises a single LED or an array of smaller LED&#39;s and emits optical energy over a 4π steradian angular distribution, at a particular CCT range, at a particular wavelength spectrum and at a particular intensity. The CCT range includes the visible light spectrum, the ultraviolet light spectrum and the infrared light spectrum. Each LED group  512  is optically coupled to a unique concentrator. 
   In an alternative embodiment of the invention, the wavelength spectrum emitted by each LED group  512  is the same. In an alternative embodiment of the invention, the LED groups  512  do not all emit the same wavelength spectrum. In an alternative embodiment of the invention, the wavelength spectrums emitted by each LED group  512  are optimized to provide a desired mix of wavelengths, such as, but not limited to, white light, or yellow light, etc. In an alternative embodiment of the invention, the LEDs are approximately 1.0 to 1.2 millimeters squared. 
   In an alternative embodiment of the invention, near field and far field color mixing is provided by distributing those LED groups  512 , which emit like wavelength spectrums, throughout the LED array  510 . In an alternative embodiment of the invention, the intensity of each LED group can be individually monitored. In an alternative embodiment of the invention, the intensity of each LED group  512  can be individually increased, decreased, turned off or turned on. In an alternative embodiment of the invention, the intensity of each LED within each LED group  512  can be individually increased, decreased, turned off or turned on. 
   In an alternative embodiment of the invention, the LED&#39;s within each LED group  512  includes a back reflector to capture additional optical energy and direct the optical energy to a corresponding concentrator. In an alternative embodiment of the invention, optical requirements of the illumination region  560  determine the type, quantity and location of the LED&#39;s within LED array. 
   In an alternative embodiment of the invention, the LED groups  512  are positioned in an optimal location to increase thermal dissipation. In an alternative embodiment of the invention. the LED groups  512  are positioned in an optimal location to obtain a desired CCT range in the illumination region  560 . 
   The heat sink  520  is thermally attached to each LED group  512 . In an alternative embodiment of the invention, the LED within each LED group  512  are thermally attached to the heat sink  520  by a thermally conductive material, such as, but not limited to solder, conductive epoxy, etc. 
   In an alternative embodiment of the invention, the heat sink  520  is cooled by water to effectuate the dissipation of thermal energy. In an alternative embodiment of the invention. the heat sink  520  uses conductive cooling to dissipate thermal energy. In an alternative embodiment of the invention, the size, shape, and material of the heat sink is optimized to maximize the amount of thermal energy that the heat sink  520  dissipates. 
   In an alternative embodiment, the heat sink  520  anchors the multi-wavelength LED array illumination system  500  to a host, such as, but not limited to a mechanical device, a human, a casing, etc. 
   In an alternative embodiment of the invention, the heat sink includes fins. Fins provide greater surface area for increased thermal energy dissipation. In an alternative embodiment of the invention, forced convection is used to dissipate thermal energy from the multi-wavelength LED array illumination system  500  and, more specifically, thermal energy from the heat sink  520  and/or thermal energy from each LED group  512 . 
   In an alternative embodiment of the, invention, the heat sink  520  material includes copper. In an alternative embodiment of the invention, the heat sink  520  material includes aluminum. In an alternative embodiment of the invention, the heat sink  520  material includes material that has a high thermal and electrical conductivity. 
   In an alternative embodiment of the invention, a heat spreader is positioned between the heat sink  520  and the LED groups  512 . A heat spreader pulls the thermal energy laterally away from the thermal energy source (i.e., the LED groups  512 ) and, thus, decreases the effective heat flux (heat power/unit area) impingent upon the heat sink  520 . Increased thermal dissipation provides for increased electric efficiency within the LED groups  512 . In a preferred embodiment of the invention, the heat spreader material includes diamond. Diamond has a high thermal conductivity (relative to the heat sink  512 ). In an alternative embodiment of the invention, the heat spreader material includes any material with a high conductivity, such as, but not limited to copper, aluminum, etc. In a preferred embodiment of the invention, the heat spreader is thermally attached to the heat sink  520 . 
   The ceramic board  530  provides an electrical path to the LED&#39;s within the LED groups  512 . The ceramic board is mounted on the heat sink  520  and provides cut-outs through which the LED&#39;s within the LED groups  512  are mounted to the heat sink  520 . The ceramic board includes metalized traces. In an alternative embodiment of the invention, a heat spreader contains a cutout or window which provide the LED groups electrical contact to the ceramic board  530  and the heat sink  520 . 
   In an alternative embodiment of the invention, the N-type electrical contact is directly bonded to the heat sink  520 . In an alternative embodiment of the invention, the N-type electrical contact is wire bonded to the heat sink  520  from the top of the LED die within the LED group  512 . In an alternative embodiment of the invention, the P-type contacts are wire bonded to electrical traces located on the ceramic board  530 . An electrical power source is electrically connected to the heat sink  520 . 
   The array of concentrators  540  includes an individual concentrator  542  for each LED group  512  Each concentrator  542  is optically coupled to the corresponding LED group  512 . Each concentrator  542  is positioned to capture optical energy emitted from each LED group  512  and includes an entrance aperture and an exit aperture. Optical energy is received from each LED group  512  via the entrance aperture of each concentrator  542 . Each concentrator  542  then aligns the received or captured optical energy from the corresponding LED group  512  and then outputs the aligned optical energy through the exit aperture of each concentrator  542 . 
   In a preferred embodiment of the invention, each concentrator  542  is a non-imaging concentrator. In a preferred embodiment of the invention, each concentrator  542  is a CPC concentrator. In a preferred embodiment of the invention, each concentrator  542  is flush with the corresponding LED groups  512 . 
   In an alternative embodiment of the invention, a non-imaging concentrator  542  is constructed with a high order polynomial surface representing the attributes of the non-imaging concentrator form. In an alternative embodiment of the invention, the aspheric sag equation is tuned to match an appropriate non-imaging concentrator form. In an alternative embodiment of the invention, any mathematical representations that approximate the ideal non-imaging concentrator provides the concentrator profile. 
   In a preferred embodiment of the invention, each concentrator  542  includes a reflective coating on the inside surface to provide for an optically efficient transfer of optical energy from the entrance aperture of each concentrator  542  to the exit aperture of each concentrator  542 . In a preferred embodiment of the invention, the concentrator  542  includes a dielectric material to provide for an optically efficient transfer of optical energy from the entrance aperture of each concentrator  542  to the exit aperture of each concentrator  542 . In a preferred embodiment of the invention, any area between the each LED group  512  and each corresponding concentrator  542  is filled with an optically clear cement or gel to match the refractive index (e.g., when the concentrator is filled with a dielectric material.). 
   In a preferred embodiment of the invention, each concentrator  542  includes a dielectric material. In a preferred embodiment of the invention, each concentrator  542  includes a dielectric material that has a sufficient index of refraction to permit total internal reflection. In a preferred embodiment of the invention, each concentrator  542  is made of a hollow reflector. In a preferred embodiment of the invention, each concentrator  542  is made of a dielectric material. 
   In an alternative embodiment of the invention, the array of concentrators  540  includes nineteen concentrators. In a preferred embodiment of the invention, the nineteen concentrators  542  are positioned in hexagonal close pack array. The position of the concentrators dictates the positions of the LED groups. 
   A single LED and single concentrator system that emits the same to similar optical power as the LED and concentrator array system uses the same amount of electrical power. However, by using an array of LED&#39;s and concentrators, the thermal energy created by the LED&#39;s is more easily dissipated due to the geometrical distribution of the LEDs&#39; positions. In other words, the single system has large focused amount of thermal energy at one point (i.e., the thermal flux is isolated in one spot), whereas the array system has smaller amounts of optical energy disbursed over numerous locations (i.e., the heat flux is spread out). Furthermore, since array system more efficiently dissipates heat, the optical power is not reduced due to electrical inefficiency when compared the optical power created by the single system. 
   In an alternative embodiment of the invention, the LED and concentrator array system when compared to a system with one LED and one concentrator and provide same to similar amounts of optical power and angular distribution, the LED and concentrator array system is significantly shorter than the single LED and once concentrator system. 
   In an alternative embodiment of the invention, a phosphor layer is placed between a concentrator  542  and light group  512 . The phosphor layer creates optical energy at a specific wavelength range when stimulated by optical energy of a different wavelength range. In an alternative embodiment of the invention, the use of a phosphor layer is used to optimize the output wavelength of the multi-wavelength LED array illumination system  500 . 
   The light integrator  550  is optically coupled via its entrance facet  552  to the exit apertures of the array concentrators  542 . The multi-sided light pipe that interfaces to the array of concentrators assures that the near field intensity at its output will be uniformly distributed over its exit face. In an alternative embodiment of the invention, the far field intensity is uniform when the entrance apertures of the array of concentrators  542  are uniformly filled. 
   In an alternative embodiment of the invention, the optical efficiency of the multiwavelength LED array illumination system  500  is optimized by positioning the LED and concentrator array in the same shape as the entrance aperture of the light pipe. 
   In an alternative embodiment of the invention, the light pipe  550  mixes the optical energy from the exit apertures of each concentrator  542 . In an alternative embodiment of the invention, the light pipe is faceted, which optimizes the mixing efficiency. A circular light pipe is a poor mixer of optical energy. A faceted light pipe is a more efficient mixer than a circular light pipe. However, the higher the number of facets, the closer the circumference approaches a circle, the mixing efficiency wanes. In addition, a light pipe with an even number of facets is a more efficient mixer than a light pipe with an odd number of facets. The optimum number of facets (i.e. for optimum mixing) is eight. In an alternative embodiment of the invention, the light pipe  550  has eight facets or sides. In order to fully benefit from the optimal mixing efficiencies. however, the entrance aperture of each concentrator in the array must be fully filled and the array shape must correspond to the hexagonal shape of the light pipe. In an alternative embodiment of the invention, the LED and concentrator array is hexagonal in shape. In an alternative embodiment of the invention, the entrance aperture of each concentrator  543  is fully filled. In an alternative embodiment of the invention, the light pipe  550  is hexagonal. 
   In an alternative embodiment of the invention, the array of concentrators  540  is molded as one unit. Molding the concentrators together reduce optical losses. In an alternative embodiment of the invention, the array of concentrators  540  and the light pipe are all molded together as one unit. 
   In an alternative embodiment of the invention, any optical element that directs or modifies optical energy is optically coupled to the exit apertures of the concentrators  542  in the array of concentrators  540 . 
   In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  includes a single concentrator. In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  includes a prism to capture and direct the optical energy exiting the exit aperture of a single concentrator. In an alternative embodiment of the invention, the prism directs optical energy orthogonally. 
   The illumination region  560  is optically coupled to exit facet  554  of the light integrator  550 . The illumination region  560  begins at the exit facet  554  of the light integrator  550 . In a preferred embodiment of the invention, the optical power emitting at the exit facet  554  of the light integrator  550  is approximately ten to eighteen percent of the input electrical power. In an alternative embodiment of the invention, the illumination region  560  is optically coupled to the exit apertures of each concentrator  542 . In an alternative embodiment of the invention, the illumination region  560  is optically coupled to a single exit aperture. 
   The target  570  is positioned within the illumination region  560 . In a preferred embodiment of the invention, the target  570  is positioned within the near field of the illumination region  560 . 
   In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  produces white light. In an alternative embodiment of the invention, LED array  510  includes a blue LED, a red LED, and a green LED to produce white light in the illumination region  560 . In an alternative embodiment of the invention, blue LED is cycled off and the remaining red LED and green LED combine to produce yellow light. In an alternative embodiment of the invention, yellow light (i.e., fog lights) is instantly produced from white light by turning off the blue LED. 
   The longer wavelength yellow color does not scatter as much as the shorter wavelength blue color. The scattering of the light through the water particles reduces visibility when driving in foggy or rainy conditions. 
   In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  produces optical energy with a CCT range of 4100K to 4900K and a CRI value of 92 , both of which satisfy the major surgical lighting industry requirements. 
   In an alternative embodiment of the invention, the multi-wave length LED array illumination system  500  provides illumination for automotive lighting which includes, but is not limited to, automotive head lights, automotive secondary head lights, automotive fog lights, automotive indicator lights. In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  provides optical energy source for automotive illumination lighting and automotive indicator lighting, etc. 
   In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  provides illumination for medical lighting which includes, but is not limited to, overhead (or major) surgical lighting, endoscope illumination at the distal end, surgical head lights. PDT illumination, and an UV Bilirubin blanket. 
   In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  provides optical energy for dental field applications which include, but are not limited to, curing, tooth whitening, illumination for a portable head light, illumination for intra-oral cameras, etc. 
   In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  provides optical energy for consumer applications which include, but are not limited to, head lighting, bike lighting, high end flashlights, an automotive trouble light, a light therapy box, and a miner&#39;s head light, etc. 
   In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  provides optical energy for safety applications, which include, but are not limited to, strobe lighting, beacons, etc. 
   In an alternative embodiment of the invention, the multi-wavelength LED array illumination system  500  provides optical energy for industrial applications which include, but are not limited to, machine vision lighting, display lighting, UV spot curing light, decorative lighting system, food inspection equipment. 
   While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.