Patent Publication Number: US-2022235916-A1

Title: Light Source Converter

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/834,677 filed Apr. 16, 2019 entitled “Light Source Converter”, which is incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to a light source converter for use with an optical device and, more particularly, to a light source converter for use with an optical device having a volumetric phosphor core. 
     BACKGROUND OF THE INVENTION 
     Since the invention of the first solid state lighting (SSL) devices in the 1920&#39;s there has been a concentrated push towards their use as alternatives to contemporary light sources. In the 1960&#39;s the first bright SSL devices were invented and their use as a source of light in the industrial and consumer fields climbed sharply. The next major goal of SSL device research was to discover a new way to produce white light, and this was mainly accomplished by the mixing of narrow band red, blue, and green (RGB) light sources. This kind of mixing poses a multitude of issues compared to broad spectrum ‘white’ light that is expected, such as reproduction of color accuracy and temperature. 
     The next stage in the evolution of SSL devices came about in the 1990s when bright blue light emitting diodes (LEDs) were invented and subsequently mated with a thin layer of phosphor coating. This layer of phosphor coating may interact with the blue light emitted from the diode and subsequently convert the light into a broad spectrum emission with a peak at a longer wavelength than that of the incident blue light. The mixing of non-converted blue light and the converted light gives a much better reproduction of broad spectrum ‘white’ light than previous discrete RGB mixing methods. 
     Lasers emit light through optical amplification based on the stimulated emission of electromagnetic radiation. Lasers are generally distinguished over other light sources because of their spatial coherence. Spatial coherence is typically expressed through the output of a laser being a narrow beam, which is diffraction limited. Lasers also have temporal coherence, which allows them to emit light with a narrow spectrum and as a result, a single color of light. Lasers have long been used where light of the required spatial or temporal coherence may not be produced using simpler technologies. 
     Traditionally, the only way to make the phosphor conversion function properly within an SSL device was to coat the light emitting source in a thin layer of phosphor material. Subsequent research showed that a large percentage of the incident blue light was reflecting off the phosphor coating and, therefore, not being converted, leading to a large loss of usable light and a reduced overall efficiency. A response to this was remote phosphor, a method in which the phosphor conversion material is offset from the light emitting source by a distance. By placing the conversion material a short distance away from the light emitting source, the possibility of errant reflections was decreased and a higher conversion efficiency was created from an otherwise identical SSL device. The remote phosphor was typically a lens or cap made from a transparent medium coated in a very thin layer of phosphor and positioned away from the light emitting source. 
     While remote phosphor is an improvement over older SSL devices, in which the light emitting source was directly covered in phosphor, having a thin layer of conversion material to work with may pose several issues. These issues may include a limitation on the amount of emitted light that can be converted before the phosphor is saturated, a direct correlation between the surface area of the emission source and the amount of phosphor that can be exposed, the concentration of temperature on a thin surface, and the overall efficiency of the conversion system. 
     Accordingly, there is a need for a light converter that can efficiently convert a large amount of emitted light to a different wavelength 
     BRIEF SUMMARY OF THE INVENTION 
     In one embodiment, there is a light source converter including a non-homogeneous conversion core optically coupled to a light source, the conversion core having a transmitting medium comprised of a plurality of layers, a proximal end, a distal end, and a length extending between the proximal end and the distal end. The light source converter further including a plurality of phosphor particles volumetrically suspended in each of the plurality of layers of the transmitting medium, a density of the plurality of phosphor particles in one of the plurality of layers proximate the proximal end of the conversion core differing from a density of the plurality of phosphor particles in another of the plurality of layers proximate the distal end of the transmitting medium. 
     In one embodiment, the plurality of phosphor particles includes two or more phosphor particle percentages, compositions and/or chemistries. The two or more phosphor particle percentages across the length of the transmitting medium may be from approximately 0% to approximately 100% or from approximately 0.1% to approximately 25%. 
     In one embodiment, the plurality of phosphor particles includes two or more phosphor types. One or more of a percentage, chemistry, and composition of the two or more phosphor particles may be configured to continuously broaden an absorption band of light from the light source. 
     In one embodiment, the volumetric suspension of the plurality of phosphor particles forms a gradient phosphor core. The gradient phosphor core may be a continuous or discontinuous gradient phosphor core. 
     In one embodiment, a thickness of each of the plurality of layers is approximately 30 microns to approximately 30 microns less than the total length of the transmitting medium. A thickness of each of the plurality of layers may be approximately from 0.01 mm to approximately 25 mm. 
     In one embodiment, the density of the plurality of phosphor particles increases or decreases from the proximal end to the distal end. 
     In one embodiment, the transmitting medium is comprised of a semi-transparent material configured to allow certain visible wavelengths of light to pass unimpeded through the transmitting medium. Transmitting medium may be comprised of polypropylene, glass, acrylic, ceramics, polycarbonate, optical polymers, polyesters, polystyrenes, polyethylenes, polyurethanes, olefins, copolymers, gels, hydrogels, glassy, crystalline, and/or supercooled liquids. 
     In one embodiment, the transmitting medium is comprised of polypropylene, glass, acrylic, ceramics, and/or polycarbonate. 
     In one embodiment, the conversion core is configured to modify optical properties of light from the light source by diffusion, absorption, and/or redirecting specific wavelengths of light. 
     In one embodiment, each of the plurality of phosphor particles has a generally predetermined position in the plurality of layers. The plurality of phosphor particles may be generally equally spaced from one another across each cross section along the length of the conversion core, wherein each cross-section is taken normal to the length of the conversion core. 
     In one embodiment, each of the plurality of layers is comprised of multiple sublayers each having the same phosphor particle density and/or phosphor particle chemistry within a sublayer. Each of the plurality of layers may have the same phosphor particle density and/or phosphor particle chemistry across a length of the each of the plurality of layers. 
     In one embodiment, the light source is a laser. The light source may output a first spectrum of radiation and the conversion core may output a second spectrum of radiation different than the first spectrum. 
     In one embodiment, at least two layers of the plurality of layers differ in phosphor particle percentage, phosphor particle density, phosphor particle composition and/or phosphor particle chemistry. 
     In one embodiment, the volumetric suspension of the plurality of phosphor particles is a discontinuous volumetric suspension including a non-linear, monotonic or polytonic suspension. 
     Another embodiment of the present invention provides for an optical device including a laser light source. The optical device may include a non-homogeneous conversion core optically coupled to the laser light source, the conversion core having a proximal end, a distal end, a length extending between the proximal end and the distal end, and a transmitting medium comprised of a transparent or translucent material and a plurality of layers. The optical device may further include a plurality of phosphor particles volumetrically suspended in each of the plurality of layers of the transmitting medium, each layer further arranged in a sequence of sublayers, each of the phosphor particles having a generally predetermined position in the sequence of sublayers and thicker layers or groups of layers, a density of the plurality of phosphor particles proximate the proximal end of the conversion core differing from a density of the plurality of phosphor particles proximate the distal end of the conversion core to form a gradient phosphor core. The gradient phosphor core may be configured to continuously broaden a spectrum of light absorption from the laser light source along the length of the conversion core. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of embodiments of the light source converter, will be better understood when read in conjunction with the appended drawings of an exemplary embodiment. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
         FIG. 1  is a schematic diagram of a prior art light source converter having a homogeneous volumetric phosphor conversion core; 
         FIG. 2A  is a schematic diagram of a light source having a light source converter, having a volumetric phosphor conversion core and a continuous density gradient in accordance with an exemplary embodiment of the present invention; 
         FIG. 2B  is a schematic diagram of a light source converter, having a volumetric phosphor conversion core and a continuous density gradient in accordance with an exemplary embodiment of the present invention; 
         FIG. 3  is a schematic diagram of a light source converter, having a volumetric phosphor conversion core and a discontinuous density gradient in accordance with an exemplary embodiment of the present invention; 
         FIG. 4  is a schematic diagram of a light source converter, having a volumetric phosphor conversion core and a discontinuous density gradient in accordance with an exemplary embodiment of the present invention; 
         FIG. 5  is a schematic diagram of a light source converter, having a volumetric phosphor conversion core and a continuous density gradient, having two different phosphor types in accordance with an exemplary embodiment of the present invention; 
         FIG. 6  is a schematic diagram of a light source converter, having a volumetric phosphor conversion core and a discontinuous density gradient, having two different phosphor types in accordance with an exemplary embodiment of the present invention; 
         FIG. 7  is a schematic diagram of a light source converter, with an intentional distribution of phosphor particles as a sequence of layers in a transmitting medium, having the density of the particles increase in a discontinuous gradient from the left to right of the transmitting medium (and type of phosphor also changes from the left to right of the transmitting medium in four stages) and a non-homogeneous gradient volumetric phosphor conversion core, in accordance with an exemplary embodiment of the present invention; 
         FIG. 8  is a graph illustrating density of phosphor particles distributed throughout the transmitting medium along the y-axis and length of the volumetric phosphor conversion core along the x-axis, in accordance with an exemplary embodiment of the present invention; 
         FIG. 9  is a graph illustrating density of phosphor particles distributed throughout the transmitting medium along the y-axis and the length of the volumetric phosphor conversion core along the x-axis, in accordance with an exemplary embodiment of the present invention; 
         FIG. 10  is a graph illustrating density of phosphor particles distributed throughout the transmitting medium along the y-axis the length of the volumetric phosphor conversion core along the x-axis, in accordance with an exemplary embodiment of the present invention; 
         FIG. 11  is a graph illustrating density of phosphor particles distributed throughout the transmitting medium along the y-axis and the length of the volumetric phosphor conversion core along the x-axis, in accordance with an exemplary embodiment of the present invention; 
         FIG. 12  is a graph illustrating density of phosphor particles distributed throughout the transmitting medium along the y-axis and length of the volumetric phosphor conversion core along the x-axis, in accordance with an exemplary embodiment of the present invention; 
         FIG. 13  is a schematic diagram of a light source converter, illustrating the arrangement of layers and sublayers; 
         FIG. 14A  is a schematic diagram of a light source converter, illustrating an exemplary radial arrangement of phosphor particle density within the volumetric phosphor conversion core; 
         FIG. 14B  is a schematic diagram of a light source converter, illustrating an exemplary radial arrangement of phosphor particle density within the volumetric phosphor conversion core; and 
         FIG. 14C  is a schematic diagram of a light source converter, illustrating an exemplary radial arrangement of phosphor particle density within the volumetric phosphor conversion core. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS OF THE INVENTION 
     Embodiments of the present invention may provide a method for volumetrically disposing phosphor compounds in a carrying medium wherein the percent of phosphor by volume may vary. The benefits of a volumetric gradient phosphor core over the current system of using a thin, uniformly distributed, coating on a remote surface are numerous and described herein. A benefit of a volumetric phosphor core may be that a much larger volume of a phosphor compound may be exposed to incident light without the use of specialized optics. A larger amount of phosphor being available for use in the conversion process, without increasing the surface area exposed to incident light, may greatly increase the efficiency of the system, while allowing for a comparatively smaller overall size for the light source for the subsequent light output. 
     An advantage arises from disposing the phosphor compound in a gradient distribution within the carrying medium as compared to current thin coating methods. Using a gradient distribution may allow for more precise control of the characteristics of the converted output light. The precise control arising from the gradient distribution may assist with aspects of the output light such as, but is not limited to, better color reproduction, a more controllable color temperature, a more controllable peak wavelength, better temperature handling, better mixing of narrow band incident light and broad band emitted light, a more temperature stable system, and a more efficient conversion process. 
     Embodiments of the invention may provide either a step-wise (discontinuous) gradient or a smooth (continuous) gradient distribution of phosphor material within the carrying medium. Such a distribution may be, but is not limited to, linear, non-linear, monotonic, polytonic, etc. The gradient distribution may also constitute changes in the thickness of distribution layers that range, for example, but not limited to, from 30 microns to 30 microns less than the length of the whole core. This type of gradient may be achieved by using a manufacturing process that creates layers. Each layer may be comprised of multiple sublayers. Each sublayer may be comprised of similar or identical phosphor particle density and composition. The manufacturing process may create and combine the layers through a variety of methods, such as but not limited to, lamination, hydrothermal synthesis, sintering, fusing, deposition, sol gel process, gel combustion, diffusion bonding, chemical precipitation, coprecipitation, solid-state/wet-chemical synthesis, and/or adhesives. 
     The manufacturing process may also allow for the intentional use of a plurality of phosphor compounds in the same phosphor core, a plurality of phosphor particle sizes, as well as distributing the different phosphor compounds in different concentrations. This can lead to even more precise control of the converted output light. The manufacturing process also involves intentionally choosing the percentage, size, and type of phosphor that is to be suspended in the transmitting medium to ensure that the output light fits the requirements for each use case. The manufacturing process also allows for the intentional arrangement of a sequence of thin sublayers of the carrying medium, now mixed with phosphor particles at a pre-determined percentage, into a thicker layer or group of layers leading to a more precise light output. The individual sublayers may have similar or identical phosphor particle density, size, and/or composition between the sublayers within the individual layers. Having similar phosphor particle density and composition in the sublayers within each layer may allow for specific control of phosphor particle arrangement in the respective layers and the transmitting medium overall. At a minimum, the thickness of a sublayer may be the diameter of one phosphor particle. The thickness of a sublayer is dependent on the light conversion and modulation properties required per use case. Each layer may be comprised of tens, hundreds, thousands, or millions of sublayers. Throughout the process, an optimization workflow is established which continuously improves the efficiency and control of the phosphor particle suspension, based on rigorously tested observations. 
     An embodiment of the invention may be a non-homogeneous gradient volumetric phosphor conversion core wherein the lowest concentration of phosphor may be located on the side where the incident light enters the conversion core, and the highest concentration of phosphor may be located distal from the side where the incident light enters the conversion core. Another embodiment of the invention may be a non-homogeneous gradient volumetric phosphor conversion core wherein the lowest and highest concentrations of phosphor may be located within the conversion core but are not necessarily oriented from lowest to highest concentration, relative to the incident light. Such an embodiment of the invention may be a non-homogeneous gradient volumetric phosphor conversion core wherein the lowest and highest concentrations of phosphor may be located within the conversion core and the concentration of the phosphor may vary in a radial distribution from the center axis of the core. Such an embodiment, for example, could have the highest concentration at the center decreasing radially outwards in the core. Another such embodiment, for example, could have the lowest concentration at the center increasing radially outward. 
     The present invention may relate to an improved method of efficiently converting narrow band light into broad spectrum light of longer wavelength. For example, a narrow band blue light with a peak wavelength at 450 nm can be converted into a broad spectrum light that ranges from 450 nm to 750 nm. In a second example, a narrow band green light with a peak wavelength at 515 nm can be converted into a broad spectrum light that ranges from 900 nm to 3 microns. As is described below, in some embodiments, a gradient volumetric phosphor conversion core has been developed. 
     Referring to  FIG. 1 , there is shown a traditional approach for light conversion that is disclosed in the prior art. Light conversion system  10  may include conversion core  100  having transmitting medium  101  and a distribution of phosphor particles  102  distributed throughout the volume of transmitting medium  101 . A light source (not shown) may be optically coupled to transmitting medium  101  and may be configured to emit light  104 , wherein light  104  may enter and transmit through conversion core  100 . 
     In one embodiment, the light source is a laser that is used for the conversion process and has an output wavelength of 450 nm, and an optical power output of 100 mW. In another embodiment, the light source is a laser that is used for the conversion process and has an output wavelength of 515 nm and an optical power output of 150 mW. In yet another embodiment, the light source is a laser that is used for the conversion process and has an output wavelength of 445 nm and an optical power output of 10 W. However, the laser source may have a wavelength appropriate to excite a specifically defined phosphor material and may be, for example, but not limited to, laser radiation with wavelengths between 200 nm and 450 nm, 400 nm and 750 mm, 450 nm and 900 nm, 800 nm and 1550 nm, and others. 
     In methods illustrated in  FIG. 1 , there may exist a homogeneous distribution of phosphor particles  102  throughout the volume of conversion core  100 . Further, this homogeneous distribution of phosphor particles  102  may be arranged in a random and unintentional manner such that the beam of input light  104  may not be configured to interact with phosphor particles  102  to maximize light conversion. In one embodiment, the beam of input light  104  interacts with phosphor particle  102 , resulting in converted light  106  being emitted. In another embodiment, light  104  does not interact with phosphor particle  102 , resulting in unconverted light  108  being emitted. This random and unintentional arrangement of particles may also require the use of specialized optics to concentrate light into the transmitting medium. Conversion core  100  may also need to be positioned a short distance away from the light source to reduce the possibility of reflections. 
     Referring to  FIGS. 2A and 2B , there is shown a first exemplary embodiment of the present invention. In one embodiment, there is light conversion system  20  which includes conversion core  200  having transmitting medium  201  and a distribution of a plurality of phosphor particles  202  with a non-homogeneous volumetric suspension within conversion core  200 . In one embodiment, the manufacturing process that suspends the plurality of phosphor particles  202  may require mixing of the plurality of phosphor particles  202  with a carrier material, such as polymethyl methacrylate (PMMA). Other carrier materials may be employed, such as other optical polymers, ceramics, polyesters, polystyrenes, polycarbonates, polyethylenes, polyurethanes, olefins, copolymers, gels, hydrogels, glassy, crystalline, supercooled liquids, and other similar materials, including those not specified but having similar properties and the ability to act as carriers for phosphor particles having the described characteristic. The carrier material may comprise transmitting medium  201  in which the plurality of phosphor particles  202  are suspended in. The resultant mixture of the carrier material and the plurality of phosphor particles  202  may be compressed and extruded into individual sublayers that are then compressed, glued, and/or bonded to form conversion core  200 . The plurality of phosphor particles  202  and the carrier material, such as PMMA or ceramic material, may be varied and controlled to achieve a desired percentage of the plurality of phosphor particles  202  per thin sublayer or group of layers that is then additionally bonded with additional layers of PMMA or ceramic and phosphor particles  202  mixed together. 
     Referring to  FIG. 2A , in some embodiments, conversion core  200  is optically coupled to light source  232 , emitting light  204  which may have a first spectrum of radiation. Conversion core  200  may be used within device  230 . Device  230  may be a wireless imaging device, such disclosed in U.S. Pat. No. 10,610,089, which is hereby incorporated by reference in its entirety. Device  230  may further include optical element  233 , optical reflector  235 , package body  231 , and filter  237 . Light source  232  of device  230  may output light  204  which interacts with conversion core  200 , outputting converted light  206 . Device  230  may include optical element  233 , which may be disposed between light source  232  and conversion core  200 . Optical element  233  may redirect light  204  to conversion core  200 . Device  230  may include optical reflector  235  and filter, which may be configured to further condition converted light  206  converted by conversion core  200 . Light source  232  may be positioned anywhere, as long as light  204 , which interacts with the plurality of phosphor particles  202 , is perpendicular to the layers of conversion core  200 . 
     Referring to  FIG. 2B , conversion core  200  may have distal end  226 , proximal end  228 , and length L extending between proximal end  228  and distal end  226 . The dimensions of conversion core  200  may be in the millimeter to meter range. In some embodiments, conversion core  200  has dimensions in millimeters, centimeters, decimeters, or meters. For example, conversion core  200  may have length L of 10 mm, a width of 5 mm, and a height of 5 mm. Conversion core  200  may have length L between 1 mm and 50 mm, 5 mm and 40 mm, 10 mm and 30 mm, 20 mm and 25 mm. Conversion core  200  may have a width between 1 mm and 50 mm, 5 mm and 40 mm, 10 mm and 30 mm, or 20 mm and 25 mm. Conversion core  200  may have a height between 1 mm and 50 mm, 5 mm and 40 mm, 10 mm and 30 mm, or 20 mm and 25 mm. In one embodiment, conversion core  200  is a cylinder with length L of 10 mm and a diameter of 5 mm. In other examples, conversion core  200  has length L greater than 1 m, such as an elongated lighting tube. 
     Light  204  may enter conversion core  200  from proximal end  228 . In one embodiment, light  204  interacts with phosphor particles  202 , which converts light  204  to converted light  206  resulting in converted light  206  being emitted from conversion core  200 . Converted light  206  may have a second spectrum of radiation different than the first spectrum of radiation of light  204 . Converted light  206  being emitted from the conversion core  200  may be shown as curved to represent a different wavelength after an interaction. For example, light  204  may interact with the plurality of phosphor particles  202  thereby emitting converted light  206 , which has a different wavelength than light  204 . In another embodiment, light  204  continues through conversion core  200  without interacting with the plurality of phosphor particles  202 , resulting in unconverted light  208  being emitted from conversion core  200 . Unconverted light  208  may be light that does not interact with any of phosphor particles  202 , thus results in unconverted light  208  have the same wavelength of light  204 . In some embodiments, the wavelength of unconverted light  208  is the same as the wavelength of light  204 . 
     Conversion core  200  may produce a mix of converted light  206  and unconverted light  208 . In some embodiments, the distribution of phosphor particles  202  is volumetrically suspended in transmitting medium  201 , which may be arranged in a sequence of sublayers. The plurality of phosphor particles  202  may be generally equally spaced from one another across each cross section taken along length L of conversion core  200 . In one embodiment, the plurality of phosphor particles  202  are equally spaced from one another across each cross section taken along length L of conversion core  200 . In some embodiments, the plurality of phosphor particles  202  may be generally evenly spaced from one another across each cross section taken along length L of conversion core  200 , where evenly means the average spacing between the plurality of phosphor particles  202  is equal. In some embodiment, approximately 97%, 95%, 90%, 80%, 85% or 75% of the plurality of phosphor particles  202  may be evenly spaced apart from each other across each cross section along length L of conversion core  200 . In other embodiments, the plurality of phosphor particles  202  are non-equally spaced from another across each cross section taken along length L of conversion core  200 . For example, some of the plurality of phosphor particles  202  may clump or group within a layer or sublayer, resulting in subgroup of plurality of phosphor particles  202  being non-equally spaced. Approximately 97%, approximately 95%, approximately 90%, approximately 80%, approximately 85% or approximately 75% of the plurality of phosphor particles  202  may be equally spaced apart from each other across each cross section taken along length L of conversion core  200 . 
     The sequence of sublayers may be intentionally arranged in layers or groups of layers, each having a distribution of phosphor particles  202  disposed within, and configured to continuously broaden the absorption of light  204  from the light source. In one embodiment, the sequence of sublayers may be intentionally arranged to continuously broaden the absorption of light  204  from the light source. The distribution of phosphor particles  202  suspended in transmitting medium  201  may be non-homogeneous, as shown by the smaller percentage of phosphor particles  202  on proximal end  228  compared to the larger percentage of phosphor particles  202  on distal end  226  of the transmitting medium  201 . In some embodiments, conversion core  200  includes a continuous increase in the density of phosphor particles  202  from proximal end  228  to the density of phosphor particles  202  adjacent distal end  226 . The rate of density increase may depend on the desired goal of the output lighting. For example, conversion core  200  may include different rates of density increase based on the desired brightness, color, and/or efficiency of the overall system. In one embodiment, the density, chemistry, size, composition and/or percentage of the phosphor particles  202  near distal end  226  of conversion core  200  may differ from the density, chemistry, composition, and/or percentage of phosphor particles  202  near proximal end  228  of conversion core  200 . 
     The embodiment of  FIGS. 2A and 2B , as described herein, may be comparable to those of  FIGS. 3-7 . The light conversion process may occur by utilizing the process of fluorescence and Stokes shift in the gradient phosphor particles in the conversion core. The volumetric suspension of phosphor particles  202  may form a gradient phosphor core in conversion core  200 . In one embodiment, the specific and intentional volumetric suspension of phosphor particles  202  may lead to more phosphor particles  202  interacting with incoming light  204  and participating in light conversion. Each layer of conversion core  200  may be arranged in a matrix configuration. Increasing the percentage of phosphor particles  202  participating in the light conversion process, without increasing the surface area exposed to light  204 , may significantly increase the efficiency of the system allowing for conversion core  200  to be a smaller size. 
     In one embodiment, the arrangement, density, chemistry, composition and/or percentage of the phosphor particles  202  suspended in transmitting medium  201  leads to more phosphor particles  202  interacting with light  204  and participating in light conversion. In some embodiments, the density or percentage of phosphor particles  202  is defined by the amount of actual phosphor that is mixed into the PMMA solution, or another specified carrier medium. A combination of different chemistries or compositions of phosphor particles  202  may be used, each having their own percentage of overall solute in each-sublayer to achieve the desired result. 
     In one embodiment, the plurality of phosphor particles  202  includes two or more different percentages of phosphor particles  202  length L of conversion core  200 . The percentages of phosphor particles  202  may be the actual mixed-in percentage of phosphor particles  202  within PMMA (or another specified carrier medium) at a spot along the light-path of light  204  from the light source. The percentages of phosphor particles  202  within PMMA, or another specified carrier medium, may be changed and varied based on desired output. In one embodiment, the two or more different percentages of phosphor particles  202  across length L of conversion core  200  varies from approximately 0% to approximately 100%. For example, the two or more different percentages of phosphor particles  202  across length L of conversion core  200  may vary by 0%, 5%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100%. In another embodiment, the two or more percentages of phosphor particles  202  across length L of conversion core  200  varies from approximately 0.1% to approximately 25%. However, the two or more percentages of phosphor particles  202  across length L of conversion core  200  may vary from approximately 0.01% to approximately 25%, approximately 5% to approximately 95%, approximately 10% to approximately 75%, or approximately 15% to approximately 50%. The two or more percentages of phosphor particles  202  may be configured to continuously broaden absorption of light  204  from the light source. The different percentages of phosphor particles  202  do not have to be distributed in an aligned concentration, such as, but not limited to, low to high, high to low, etc. For example, the percentage of phosphor particles  202  may be approximately 5% at proximal end  228  and may be 15% at distal end  226 . However, the percentage of phosphor particles  202  may be between approximately 0% and approximately 100%, approximately 5% and approximately 90%, approximately 15% and approximately 80%, approximately 25% and approximately 70%, or approximately 35% and 60% at proximal end  228 , and between approximately 0% and approximately 100%, approximately 5% and approximately 90%, approximately 15% and approximately 80%, approximately 25% and approximately 70%, or approximately 35% and 60% at distal end  226 . 
     In some embodiments, the plurality of phosphor particles  202  is disposed within transmitting medium  201  of conversion core  200 . Transmitting medium  201  may be comprised of a transparent or translucent material configured to allow specified visible wavelengths of light to pass unimpeded through transmitting medium  201 . Transmitting medium  201  may be comprised of polypropylene, glass, acrylic, ceramics, polycarbonate or any other transparent material. For example, transmitting medium  201  may be comprised of a transparent multi-layered ceramic material. The properties of the transparent multi-layered ceramic material may be varied to change the color of converted light  206 . For example, the thickness of the layers of the transparent multi-layered ceramic material may be tailored to produce white light. In some embodiments, the transparent multi-layered ceramic material of transmitting medium  201  contains AlON, Al 2 O 3 , Dy 2 O 3 , PR 3+ , ND 3+ , CR 4+ , YB 3+ , Dy 3+ , Gd 3+ , and/or Ce 3+ , which may be varied to tailor the properties of converted light  206 . 
     Transmitting medium  201  may be a material into which phosphor particles  202  are able to be blended at varying temperatures. Transmitting medium  201  may be configured to modify optical properties of light  204  from the light source including diffusion, absorption, and/or redirecting specific wavelengths of light. Transmitting medium  201  may be comprised of a multilayered or blended material. In one embodiment, the thickness of an individual layer of the multiple layers of transmitting medium  201  ranges from approximately 30 microns to approximately 30 microns less than length L of conversion core  200 . In another embodiment, the thickness of an individual layer of the multiple layers of transmitting medium ranges from approximately from 0.01 mm to approximately 25 mm. The transmission mechanism of light  204  through transmitting medium  201  may be, direct, on or off axis, scattered, and/or specular. Light  204  may be modified in a few different ways including color, brightness, average wavelength, peak wavelength, etc. For example, various optical elements may be used to modify light  204 . In some embodiment, a lens is used to modify the properties of light  204 . In some embodiments, a lens is not used within light conversion system  20 . 
     Referring to  FIG. 3 , there is shown a second exemplary embodiment. In some embodiments, light conversion system  30  relates to light conversion system  20 . Light conversion system  30  may include a non-homogeneous conversion core  300  having distal end  326 , proximal end  328 , transmitting medium  301  and phosphor particles  302  and  310 . Conversion core  300  may include left-side core  314  with a distribution of a plurality of phosphor particles  310 , right-side core  316  with a distribution of a plurality of phosphor particles  302 , and layer interface  312 . Left-side core  314  and right-side core  316  may be optically coupled to a light source emitting light  304 . Layer interface  312  may be disposed between left-side core  314  and right-side core  316 . 
     Transmitting medium  301  of light conversion system  30  may be comprised of layers, which may be further comprised of individual sublayers. For example, as shown in  FIG. 3 , light conversion system  30  may be comprised of layer  318 - 1  and layer  318 - 2 . Layer  318 -N may refer to any one of the layers depicted (e.g., layer  318 - 1 , layer  318 - 2 , etc.). Layer  318 - 1  may be further comprised of individual sublayers, sublayer  320 -N. Sublayer  320 -N may refer to any of the individual sublayers depicted (e.g., sublayer  320 - 1 , sublayer  320 - 2 , sublayer  320 - 3 , sublayer  320 - 4 , sublayer  320 - 5  and/or sublayer  320 - 6 ). Similarly, layer  318 - 2  may also be comprised of individual sublayers (not shown). In one embodiment, layer  318 - 1  and layer  318 - 2  may each be comprised of six individual sublayers. The thickness of individual sublayers  320 -N may be the diameter of, for example, one phosphor particle. As such, the thickness of layer  318 -N may be defined by the thickness of individual sublayers  320 -N. For example, the thickness of layer  318 -N may be the sum of the thicknesses of all sublayers  320 -N. As described previously, having similar density and composition of phosphor particles  310  in the sublayers  320 -N within layer  318 - 1  may allow for specific control of the arrangement of phosphor particles  310  within the respective layers  318 -N and transmitting medium  301 . The specific arrangement of phosphor particles  310  may be applicable to  FIG. 2B ,  FIGS. 4-7  and  FIGS. 14A-14C  as well. 
     In one embodiment, light  304  may enter transmitting medium  301  of conversion core  300  via left-side core  314 . Light  304  may interact with phosphor particles  310 ,  302  resulting in converted light  306  being emitted from conversion core  300 . The distribution of phosphor particles  302  volumetrically suspended on right-side core  316  may be intentionally arranged in a sequence of sublayers. The sequence of sublayers may be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of light  304 . As compared with  FIGS. 1  and  2 ,  FIG. 3  may show an increased level of light conversion depicted by converted light  306  being emitted from conversion core  300  and a decrease in the depiction of unconverted light  308  being emitted from distal end  326  of transmitting medium  301 . The reduction in the amount of unconverted light  308  compared to  FIG. 1  may be due to the forming of a gradient phosphor core and/or the non-continuous gradient increase in the density of phosphor particles  310 ,  302 . 
     In one embodiment, the distribution of phosphor particles  302 ,  310  volumetrically suspended in left-side core  314  and right-side core  316  is non-homogeneous. For example, a smaller percentage of phosphor particles  310  may be volumetrically suspended in left-side core  314  as compared to a larger percentage of phosphor particles  302  that may be volumetrically suspended in right-side core  316 . In some embodiments, conversion core  300  includes a non-continuous gradient increase in the density of phosphor particles  310  from left-side core  314  to the density of phosphor particles  302  from the right-side core  316 . Further, there may be a rapid increase in the density of phosphor particles  302 ,  310  at or adjacent to layer interface  312 . 
     In some embodiments, the volumetric suspension of phosphor particles  302 ,  310  forms a gradient in transmitting medium  301  of conversion core  300 . In one embodiment, the volumetric suspension of phosphor particles  302 ,  310  leads to more phosphor particles  302 ,  310  interacting with incident light  304  and participating in light conversion. Increasing the percentage of phosphor particles  302 ,  310  participating in the light conversion process, without increasing the surface area exposed to incident light  304  and also without the need for specialized optics, may significantly increase the efficiency of light conversion system  30  while allowing for a comparatively smaller overall size. In one embodiment, the arrangement, density, chemistry, composition and/or percentage of phosphor particles  302 ,  310  suspended in transmitting medium  301  leads to more phosphor particles  302 ,  310  interacting with light  304  and participating in light conversion. 
     Referring to  FIG. 4 , there is shown a third exemplary embodiment of the present invention. In some embodiments, light conversion system  40  relates to light conversion systems  20 ,  30 . Light conversion system  40  may include volumetric non-homogeneous conversion core  400  having distal end  426 , proximal end  428 , transmitting medium  401  and phosphor particles  402 ,  410 . Conversion core  400  may be comprised of left-side core  414 , left-middle core  416 , right-middle core  418 , right-side core  420  and layer interfaces  422 ,  412  and  424 . Layer interface  422  may be disposed between left-side core  414  and left-middle core  416 . Layer interface  412  may be disposed between left-middle core  416  and right-middle core  418 . Layer interface  424  may be disposed between right-middle core  418  and right-side core  420 . 
     Each of left-side core  414 , left-middle core  416 , right-middle core  418 , and right-side core  420  of conversion core  400  may be distinguished by a certain density, composition, percentage and/or chemistry of phosphor particles  402 ,  410 . Left-side core  414  may have a unique and intentional distribution of a plurality of phosphor particles  410  and right-side core  420  may have unique and intentional distribution of a plurality of phosphor particles  402 . In some embodiments, the distribution of the plurality of phosphor particles  402  is different than the distribution of plurality of phosphor particles  410 . In another embodiment, the distribution of the plurality of phosphor particles  402  is the same as the distribution of plurality of phosphor particles  410 . 
     Transmitting medium  401  may be optically coupled to a light source emitting light  404 . Light  404  may enter transmitting medium  401  of conversion core  400  from left-side core  414 . In one embodiment, light  404  may interact with phosphor particles  410 ,  402  throughout conversion core  400  resulting in light  404  being converted to converted light  406 , which is emitted from conversion core  400 . The distribution of phosphor particles  410 ,  402  may be intentionally arranged in a sequence of sublayers in transmitting medium  401 . The sequence of sublayers may be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of light  404  from the light source. As compared with  FIGS. 1 and 2B ,  FIG. 4  depicts an increased level of light conversion. For example,  FIG. 4  depicts an increased amount of converted light  406  and no depiction of unconverted light being emitted from distal end  426  of conversion core  400 . This may be due to, for example, the forming of a gradient phosphor core and/or the discontinuous gradient increase in the density of phosphor particles  402 ,  410 . 
     The distribution of phosphor particles  402 ,  410  volumetrically suspended in transmitting medium  401  of conversion core  400  may be non-homogeneous as shown from the smaller percentage of phosphor particles  410  in left-side core  414  compared to the larger percentage of phosphor particles  402  in right-side core  420 . There may be a non-continuous gradient increase in the density of phosphor particles  410  from left-side core  414  through left-middle core  416 , through the right-middle core  418 , to right-side core  420 . Further, there may also be a rapid increase in the density of phosphor particles  402 ,  410  at or adjacent to layer interfaces  422 ,  412  and  424 . 
     Referring to  FIG. 5 , there is shown a fourth exemplary embodiment of the present invention. In some embodiments, light conversion system  50  relates to light conversion systems  20 ,  30 ,  40 . Light conversion system  50  may include volumetric non-homogeneous conversion core  500  having distal end  526 , proximal end  528 , transmitting medium  501  and phosphor particles  502 ,  510 . Phosphor particles  502 ,  510  may be volumetrically disposed within transmitting medium  501  and may have a distribution of a plurality of phosphor particles of a first type  510  and a distribution of a plurality of phosphor particles of a second type  502  throughout transmitting medium  501 . Conversion core  500  may be optically coupled to a light source emitting light  504  and may include left-side core  514  and right-side core  520 . Light  504  may enter transmitting medium  501  of conversion core  500  from left-side core  514 . In one embodiment, light  504  interacts with phosphor particles  502 ,  510  resulting in light  504  being converted to converted light  506  and emitted from conversion core  500 . 
     The distribution of phosphor particles  502 ,  510  may be intentionally arranged in a sequence of sublayers in transmitting medium  501 . The sequence of sublayers may be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of light  504 . As compared with  FIGS. 1 and 2B ,  FIG. 5  may show an increased level of light conversion depicted by converted light  506  being emitted from the conversion core  500  and may also show no depiction of light being emitted from distal end  526  of conversion core  500 . This may be due to, for example, the use of two different type of phosphor particles  502 ,  510 , the forming of a gradient phosphor core and/or the continuous gradient increase in the density of phosphor particles  502 ,  510 . 
     The distribution of phosphor particles  502 ,  510  volumetrically suspended in conversion core  500  may be non-homogeneous as shown from the smaller percentage of phosphor particles of the first type  510  volumetrically suspended in left-side core  514  of conversion core  500  as compared to the larger percentage of phosphor particles of the second type  502  volumetrically suspended in right-side core  520  of conversion core  500 . There may be a continuous gradient increase in the density of phosphor particles of the first type  510  adjacent proximal end  528  to the density of phosphor particles of the second type  502  adjacent to distal end  526 . 
     The volumetric suspension of phosphor particles  502 ,  510  may form a gradient phosphor core in conversion core  500 . In one embodiment, the volumetric suspension of phosphor particles  502 ,  510  may lead to more phosphor particles interacting with light  504  and participating in light conversion. Increasing the percentage of phosphor particles  502 ,  510  participating in the light conversion process, without increasing the surface area exposed to light  504 , may significantly increase the efficiency of light conversion system  50  while allowing for a comparatively smaller overall size for the light source for the subsequent light output. In one embodiment, the arrangement, density, chemistry, composition and/or percentage of phosphor particles  502 ,  510  suspended in transmitting medium  501  of conversion core  500  may lead to more phosphor particles  502 ,  510  interacting with light  504  and participating in light conversion. 
     Referring to  FIG. 6 , there is shown a fifth exemplary embodiment of the present invention. In some embodiments, light conversion system  60  relates to light conversion systems  20 ,  30 ,  40 ,  50 . Light conversion system  60  may include non-homogeneous conversion core  600  having proximal end  262 , proximal end  628 , transmitting medium  601 , and phosphor particles  602 ,  610 . Conversion core  600  may include left-side core  614 , right-side core  616 , layer interface  612 , a distribution of a plurality of phosphor particles of a first type  610  distributed in left-side core  614 , and a distribution of a plurality of phosphor particles of a second type  602  distributed in right-side core  616 . Conversion core  600  may be optically coupled to a light source emitting a light  604 . Light  604  may enter transmitting medium  601  of conversion core  600  from left-side core  614 . In one embodiment, light  604  may interact with phosphor particles  602 ,  610  resulting in converted light  606  being emitted from conversion core  600 . 
     The distribution of phosphor particles  602 ,  610  may be intentionally arranged in sequence of sublayers in transmitting medium  601 . The sequence of sublayers may be intentionally arranged in thicker layers or groups layers configured to continuously broaden the absorption of light  604 . As compared with  FIGS. 1 and 2B ,  FIG. 6  may show an increased level of light conversion depicted by converted light  606  being emitted from conversion core  600  and no depiction of light being emitted from distal end  626  of conversion core  600 . This may be due to, for example, the use of two different type of phosphor particles  602 ,  610 , the forming of a gradient phosphor core and/or the non-continuous gradient increase in the density of phosphor particles  602 ,  610 . 
     The distribution of phosphor particles  602 ,  610  volumetrically suspended in conversion core  600  may be non-homogeneous as shown from the smaller percentage of phosphor particles of the first type  610  volumetrically suspended in left-side core  614  of conversion core  600  as compared to the larger percentage of phosphor particles of the second type  602  volumetrically suspended in right-side core  616  of conversion core  600 . There may be a non-continuous gradient increase in the density of phosphor particles of the first type  610  from proximal end  628  to the density of phosphor particles of the second type  602  adjacent distal end  626 . Further, there may also be a rapid increase in the density of phosphor particles  602 ,  610  at layer interface  612 . 
     Referring to  FIG. 7 , there is shown a sixth exemplary embodiment of the present invention. In some embodiments, light conversion system  70  relates to light conversion systems  20 ,  30 ,  40 ,  50 ,  60 . Light conversion system  70  may include non-homogeneous conversion core  700  having proximal end  732 , distal end  730 , transmitting medium  701 , and phosphor particles  702 ,  710 ,  728 ,  726 . Conversion core  700  may include left-side core  714  with phosphor particles of a first type  710 , left-middle core  716  with phosphor particles of a second type  726 , right-middle core  718  with phosphor particles of a third type  728 , right-side core  720  with phosphor particles of a fourth type  702 , and layer interfaces  722 ,  712  and  724 . Layer interface  722  may be disposed between left-side core  714  and left-middle core  716 . Layer interface  712  may be disposed between left-middle core  716  and right-middle core  718 . Layer interface  724  may be disposed between right-middle core  718  and right-side core  720 . 
     Each of left-side core  714 , left-middle core  716 , right-middle core  718 , and right-side core  720  of conversion core  700  may be distinguished by a certain density, composition, percentage and/or chemistry. Conversion core  700  may be optically coupled to a light source emitting light  704 . Light  704  may enter transmitting medium  701  of conversion core  700  from left-side core  714 . In one embodiment, light  704  may interact with phosphor particles  702 ,  726 ,  728 ,  710  resulting in converted light  706  being emitted. The distribution of phosphor particles  702 ,  726 ,  728 ,  710  may be intentionally arranged in sequence of sublayers in transmitting medium  701 . The sequence of sublayers may be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of light  704 . As compared with  FIGS. 1 and 2B ,  FIG. 7  may show an increased level of light conversion depicted by converted light  706  being emitted from conversion core  700  and no depiction of non-converted light being emitted from distal end  730  of conversion core  700 . This may be due to, for example, the use of four different type of phosphor particles  702 ,  710 ,  726 ,  728 , forming of a gradient phosphor core and/or the continuous gradient increase in the density of phosphor particles  702 ,  710 ,  726 ,  728 . 
     The distribution of phosphor particles  702 ,  710 ,  726 ,  728 , volumetrically suspended in transmitting medium  701  of conversion core  700  may be non-homogeneous as shown from the smaller percentage of phosphor particles of the first type  710  volumetrically suspended in left-side core  714  of conversion core  700  as compared to the larger percentage of phosphor particles of the fourth type  702  volumetrically suspended in right-side core  720  of conversion core  700 . There may be a non-continuous gradient increase in the density of phosphor particles of the first type  710  from left-side core  714  through left-middle core  716  with phosphor particles of the second type  726 , through right-middle core  718  with phosphor particles of the third type  728 , through to the density of phosphor particles of the fourth type  702  adjacent right-side core  720 . There may also be a sharp increase of phosphor particles  702 ,  710 ,  726 ,  728  at a layer interfaces  712 ,  722 , and  724 . 
     Referring to  FIG. 8 , there is shown a graph illustrating the relationship between the density of phosphor particles distributed throughout the transmitting medium and the length of the volumetric phosphor conversion core. The density may increase in a single discontinuous non-linear gradient. This discontinuous increase may be shown by a step-wise graph. 
     Referring to  FIG. 9 , there is shown a graph illustrating the relationship between the density of phosphor particles distributed throughout the transmitting medium and the length of the volumetric phosphor conversion core, wherein the density may increase in a single continuous non-linear gradient. 
     Referring to  FIG. 10  there is shown a graph illustrating the relationship between the density of phosphor particles distributed throughout the transmitting medium and the length of the volumetric phosphor conversion core, wherein the density may increase in multiple discontinuous non-linear gradients. This discontinuous increase may be shown by a step-wise graph. 
     Referring to  FIG. 11  there is shown a graph illustrating the relationship between the density of phosphor particles distributed throughout the transmitting medium and the length of the volumetric phosphor conversion core, wherein the density may increase in multiple continuous non-linear gradients. 
     Referring to  FIG. 12  there is shown a graph illustrating the relationship between the density of phosphor particles distributed throughout the transmitting medium and the length of the volumetric phosphor conversion core, wherein the density may increase in a single continuous linear gradient. 
     Referring to  FIG. 13 , there is shown a schematic diagram of a light converter system, illustrating an exemplary arrangement of layers and sublayers. For example, Layer  1   1300 - 1  may be comprised of individual sublayers, Layer  2   1300 - 2  may be comprised of individual sublayers, and Layer  3   1300 - 3  may be comprised of individual sublayers. The individual sublayers of each layer  1300 - 1 ,  1300 - 2 ,  1300 - 3 , may have similar or identical phosphor particle densities and compositions. At a minimum, the thickness of a sublayer may be the diameter of a single phosphor particle. However, the thickness of a sublayer may be the diameter of two phosphor particles, three phosphor particles, four phosphor particles, or more than four phosphor particles. The thickness of a sublayer is dependent on the light conversion and modulation properties required per use case. Each layer may be comprised of tens, hundreds, thousands, or millions of sublayers. 
     Referring to  FIGS. 14A-14C , there is shown a schematic diagram of a light converter system, illustrating an exemplary radial arrangement of phosphor particle density within the volumetric phosphor conversion core. In  FIGS. 14A-14C , a higher phosphor particle density may be represented by a higher density of shading. For example, in one embodiment shown in  FIG. 14A , the phosphor particle distribution may be arranged in such a way, such that individual layers may have gradient phosphor distribution  1401  wherein the density of the phosphor particles increases from the center radially outwardly. In another embodiment shown in  FIG. 14B , individual layers may have gradient phosphor distribution  1402  wherein the density of the phosphor particles decreases from the center radially outwardly, or in any other arrangement that may be continuous or discontinuous with regards to the phosphor particle density change. In yet another embodiment shown in  FIG. 14C , these aforementioned radial layers may be arranged in a volumetric shape such as cylinder  1403 , wherein each radial layer may be different from the layers preceding and following it. The volumetric shaped described here is not limited to a cylinder, and radial layers can be used in volumetric shapes such as, but not limited to, prisms, cones, cubes, or any other solid geometry. The solid geometries that are built using these radial layers may have different densities in the radial  1404  and/or axial  1405  direction throughout. 
     It will be appreciated by those skilled in the art that changes could be made to the exemplary embodiments shown and described above without departing from the broad inventive concepts thereof. It is understood, therefore, that this invention is not limited to the exemplary embodiments shown and described, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the claims. For example, specific features of the exemplary embodiments may or may not be part of the claimed invention and various features of the disclosed embodiments may be combined. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. 
     It is to be understood that at least some of the figures and descriptions of the invention have been simplified to focus on elements that are relevant for a clear understanding of the invention, while eliminating, for purposes of clarity, other elements that those of ordinary skill in the art will appreciate may also comprise a portion of the invention. However, because such elements are well known in the art, and because they do not necessarily facilitate a better understanding of the invention, a description of such elements is not provided herein. 
     Further, to the extent that the methods of the present invention do not rely on the particular order of steps set forth herein, the particular order of the steps should not be construed as limitation on the claims. Any claims directed to the methods of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the steps may be varied and still remain within the spirit and scope of the present invention.