Light source converter

Abstract

To provide a light converter capable of efficiently converting a large amount of emitted light into light of a different wavelength.SOLUTION: There is provided a light source converter including a non-homogeneous conversion core optically coupled to a light source. The conversion core has 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 includes 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 differs from a density of the plurality of phosphor particles in another of the plurality of layers proximate the distal end of the transmitting medium.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 834,677, filed on April 16, 2019, which is incorporated herein by reference in its entirety.

[0002] The present invention generally relates to a light source converter for use with optical devices, and more specifically, to a light source converter for use with an optical device having a volumetric phosphor core.

Background Art

[0003] Since the invention of the first solid - state lighting (SSL) devices in the 1920s, their use as a replacement for existing light sources has been aggressively promoted. In the 1960s, the first high - brightness SSL devices were invented, and their use as light sources in industrial and consumer applications increased rapidly. The next major goal in SSL device research was to discover new ways to produce white light, which was mainly achieved by mixing narrow - band red, blue, and green (RGB) light sources. This type of mixing presents a number of expected problems compared to "white" light with a broad spectrum, such as color accuracy and color temperature reproduction.

[0004] The next stage in the evolution of SSL devices occurred in the 1990s when blue - light - emitting diodes (LEDs) were invented and then combined with thin layers of phosphor coatings. This layer of phosphor coating can interact with the blue light emitted from the diode and then convert the light into a broad - spectrum emission having a peak at a wavelength longer than that of the incident blue light. The mixture of unconverted blue light and converted light provides significantly better reproducibility of broad - spectrum "white" light than the previous individual RGB mixing methods.

[0005] A laser emits light through optical amplification based on stimulated emission of electromagnetic radiation. Lasers are generally distinguished from other light sources by their spatial coherence. Spatial coherence is generally represented by the fact that the output of a laser is a narrow beam that is diffraction-limited. Lasers also have temporal coherence, which allows a laser to emit light in a narrow spectral range and, as a result, to emit monochromatic light. Lasers have been used for a long time in situations where the light with the required spatial or temporal coherence cannot be generated using simpler techniques.

[0006] Conventionally, the only way to fully implement the phosphor conversion function within an SSL device was to coat the light-emitting source with a thin layer of phosphor material. As later research showed, most of the incident blue light was not converted by being reflected by the phosphor coating, resulting in a large loss of usable light and a decrease in overall efficiency. A countermeasure to this is remote phosphor, in which the phosphor conversion material is offset from the light-emitting source by a certain distance. By placing the conversion material at a short distance from the light-emitting source, the possibility of incorrect reflection is reduced, resulting in higher conversion efficiency from the same SSL device. Remote phosphors are generally lenses or caps made of a transparent medium coated with a very thin layer of phosphor and placed away from the light-emitting source.

[0007] Remote phosphors were an improvement over older SSL devices in which the light-emitting source was directly coated with phosphor, but several problems can be presented by coupling thin layers of the conversion material. These problems can include limitations in the amount of emitted light that can be converted before the phosphor saturates, a direct correlation between the surface area of the light-emitting source and the amount of phosphor that can be exposed, concentration of temperature on the thin surface, and the overall efficiency of the conversion system.

[0008] Therefore, there is a need for an optical converter that can efficiently convert a large amount of emitted light into different wavelengths. SUMMARY OF THE INVENTION

[0009] In one embodiment, there is a light source converter that includes a non-uniform conversion core optically coupled to a light source, the conversion core having a plurality of layers, a proximal end, a distal end, and a transmission medium configured with a length extending between the proximal end and the distal end. The light source converter further includes a plurality of phosphor particles volumetrically suspended in each of the plurality of layers of the transmission medium, and the density of the plurality of phosphor particles in one of the plurality of layers proximate the proximal end of the conversion core is different from the density of the plurality of phosphor particles in another one of the plurality of layers proximate the distal end of the transmission medium.

[0010] In one embodiment, the plurality of phosphor particles includes two or more phosphor particle ratios, compositions, and / or chemical properties. The two or more phosphor particle ratios across the length of the transmission medium may be from about 0% to about 100% or from about 0.1% to about 25%.

[0011] In one embodiment, the plurality of phosphor particles includes two or more phosphor species. One or more of the ratios, chemical properties, and compositions of the two or more phosphor particles may be configured to continuously broaden the absorption band of light from the light source.

[0012] 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.

[0013] In one embodiment, the thickness of each of the plurality of layers ranges from about 30 microns to about 30 microns less than the total length of the transmission medium. The thickness of each of the plurality of layers may be from about 0.01 mm to about 25 mm.

[0014] In one embodiment, the density of the plurality of phosphor particles increases or decreases from the proximal end toward the distal end.

[0015] In one embodiment, the transmission medium is composed of a translucent material configured to allow light of a specific visible wavelength to pass through the transmission medium without being obstructed. The transmission medium can be composed of polypropylene, glass, acrylic, ceramic, polycarbonate, optical polymer, polyester, polystyrene, polyethylene, polyurethane, olefin, copolymer, gel, hydrogel, vitreous, crystalline, and / or supercooled liquid.

[0016] In one embodiment, the transmission medium is composed of polypropylene, glass, acrylic, ceramic, and / or polycarbonate.

[0017] In one embodiment, the conversion core is configured to modify the optical properties of light from a light source by diffusion, absorption, and / or redirection of light of a specific wavelength.

[0018] In one embodiment, each of the plurality of phosphor particles has a generally predetermined position within the plurality of layers. The plurality of phosphor particles may be generally evenly spaced from each other across each cross-section along the length of the conversion core, and each cross-section is perpendicular to the length of the conversion core.

[0019] In one embodiment, each of the plurality of layers is composed of a number of sub-layers each having the same phosphor particle density and / or phosphor particle chemical properties within the sub-layer. Each of the plurality of layers may have the same phosphor particle density and / or phosphor particle chemical properties over the length of each of the plurality of layers.

[0020] In one embodiment, the light source is a laser. The light source may output a first emission spectrum, and the conversion core may output a second emission spectrum different from the first spectrum.

[0021] In one embodiment, at least two of the plurality of layers differ in phosphor particle ratio, phosphor particle density, phosphor particle composition, and / or phosphor particle chemical properties.

[0022] In one embodiment, the volumetric suspension of the plurality of phosphor particles is a discontinuous volumetric suspension including non-linear, monotonic, or multi-tonic suspension.

[0023] Other embodiments of the present invention provide an optical device including a laser light source. The optical device may include a non-uniform 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 transmission medium composed 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 transmission medium, each layer being further arranged in a series of sub-layers, each of the phosphor particles having a generally predetermined position within the series of sub-layers and a thicker layer or group of layers, and the density of the plurality of phosphor particles proximate to the proximal end of the conversion core being different from the density of the plurality of phosphor particles proximate to the distal end of the conversion core, forming a gradient phosphor core. The gradient phosphor core may be configured to continuously broaden the light absorption spectrum from the laser light source along the length of the conversion core.

[0024] The above summary, as well as the following detailed description of embodiments of the light source converter, will be more appropriately understood when read in conjunction with the accompanying drawings of the exemplary embodiments. However, it should be understood that the present invention is not limited to the configurations and means shown as such.

Brief Description of the Drawings

[0025]

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[0026] Embodiments of the present invention may provide a method for volumetrically disposing a fluorescent compound in a carrier medium where the volume percentage of phosphor particles can vary. Relative to current systems that use a thin, uniformly distributed coating on a remote surface, there are numerous advantages to a volumetric gradient phosphor core, as described herein. An advantage of a volumetric phosphor core may be that a significantly greater amount of fluorescent compound can be exposed to incident light without using a dedicated optical system. By having a large amount of phosphor available in the conversion process without increasing the surface area exposed to incident light, the overall size of the system can be relatively small for a subsequent light output source while significantly increasing the efficiency of the system.

[0027] Advantages result from disposing the fluorescent compound in a gradient distribution within the carrier medium as compared to current thin film methods. Using a gradient distribution may enable more precise control of the characteristics of the converted output light. The precise control resulting from the gradient distribution may assist in aspects of the output light such as, but not limited to, good color reproducibility, a highly controllable color temperature, a highly controllable peak wavelength, good temperature operation, good mixing of narrowband incident light and broadband emitted light, a highly temperature stable system, and a highly efficient conversion process.

[0028] Embodiments of the present invention may provide a stepwise (discontinuous) or smooth (continuous) gradient distribution of phosphor materials within a carrier medium. Such distributions may be, but are not limited to, linear, non-linear, monotonic, multi-tonic, etc. The gradient distribution may also be a change in the thickness of a distribution layer that ranges, for example, from about 30 microns to about 30 microns less than the full length of the core (thickness). This type of gradient can be achieved using a manufacturing process that produces the layer. Each layer may be composed of a number of sub-layers. Each sub-layer may be composed of the same or identical phosphor particle density and composition. This manufacturing process may form and bond the layer by various methods such as, but not limited to, lamination, hydrothermal synthesis, sintering, fusion bonding, deposition, sol-gel process, gel combustion, diffusion bonding, chemical precipitation, co-precipitation, solid / wet chemical synthesis, and / or adhesion.

[0029] This manufacturing process may also enable the intentional use of multiple fluorescent compounds within the same phosphor core, multiple phosphor particle sizes, and the dispersion of different fluorescent compounds at different concentrations. This can result in more precise control of the converted output light. This manufacturing process also involves the intentional selection of the proportion, size, and type of phosphor floating within the transmission medium to ensure that the output light meets the requirements of each use case. This manufacturing process also enables the intentional arrangement of a series of thin sub-layers of the carrier medium, which is currently mixed with phosphor particles at a given proportion, into thicker layers or groups of layers that provide more precise light output. The individual sub-layers may have the same or identical phosphor particle density, size, and / or composition between the sub-layers within an individual layer. By having similar phosphor particle density and composition in the sub-layers within each layer, specific control of the phosphor particle arrangement within each layer and throughout the transmission medium may be possible. At a minimum, the thickness of the sub-layer may be the diameter of one phosphor particle. The thickness of the sub-layer depends on the light conversion and modulation characteristics required for each use case. Each layer may be composed of dozens, hundreds, thousands, or millions of sub-layers. Throughout the process, an optimal workflow is established that continues to improve the efficiency and control of phosphor particle suspension based on rigorously tested observations.

[0030] Embodiments of the present invention may be a non-uniform gradient volume-type phosphor conversion core in which the phosphor with the lowest concentration exists on the side where incident light enters the conversion core, and the phosphor with the highest concentration may exist distally from the side where the incident light enters the conversion core. Other embodiments of the present invention may be a non-uniform gradient volume-type phosphor conversion core in which the phosphor with the lowest and highest concentrations may exist in the conversion core, but is not necessarily arranged from the lowest to the highest with respect to the incident light. Such embodiments of the present invention may be a non-uniform gradient volume-type phosphor conversion core in which the phosphor with the lowest and highest concentrations exists in the conversion core, and the concentration of the phosphor may vary in a radial distribution from the central axis of the core. Such embodiments may, for example, have the highest concentration at the center and a concentration that decreases radially outward within the core. Other such embodiments may, for example, have the lowest concentration at the center and a concentration that increases radially outward.

[0031] The present invention may relate to an improved method for efficiently converting narrowband light into broadband spectrum light of a longer wavelength. For example, narrowband blue light having a peak wavelength of 450 nm can be converted into broadband spectrum light in the range of 450 nm to 750 nm. In a second example, narrowband green light having a peak wavelength of 515 nm can be converted into broadband spectrum light in the range of 900 nm to 3 microns. As will be described below, in some embodiments, a gradient volume-type phosphor conversion core is deployed.

[0032] Referring to FIG. 1, a conventional approach for optical conversion disclosed in the prior art is shown. The optical conversion system 10 may include a conversion core 100 having a transmission medium 101 and a distribution of phosphor particles 102 dispersed throughout the volume of the transmission medium 101. A light source (not shown) may be optically coupled to the transmission medium 101 and configured to emit light 104, which may enter the conversion core 100 and transmit through the conversion core 100.

[0033] In one embodiment, the light source is a laser used for the conversion process and having an output wavelength of 450 nm and an optical power output of 100 mW. In other embodiments, the light source is a laser used for the conversion process and having an output wavelength of 515 nm and an optical power output of 150 mW. In still other embodiments, the light source is a laser used for the conversion process and having an output wavelength of 445 nm and an optical power output of 10 W. However, the light source may have a wavelength suitable for exciting a well-defined fluorescent material, and may be, for example but not limited to, laser radiation having wavelengths in the range of 200 nm to 450 nm, 400 nm to 750 nm, 450 nm to 900 nm, 800 nm to 1550 nm, and other wavelengths.

[0034] In the method shown in FIG. 1, a uniform distribution of phosphor particles 102 may exist throughout the volume of the conversion core 100. Also, since this uniform distribution of phosphor particles 102 may be arranged in a random and unintentional manner, the rays of the input light 104 may not be configured to interact with the phosphor particles 102 so as to maximize the optical conversion. In one embodiment, the rays of the input light 104 interact with the phosphor particles 102, and as a result, converted light 106 is emitted. In other embodiments, the light 104 does not interact with the phosphor particles 102, and as a result, unconverted light 108 is emitted. This random and unintentional particle arrangement may also require the use of a dedicated optical system to concentrate the light in the transmission medium. Also, the conversion core 100 may need to be placed at a short distance from the light source to reduce the possibility of reflection.

[0035] Referring to FIGS. 2A and 2B, a first exemplary embodiment of the present invention is shown. In one embodiment, there is an optical conversion system 20 including a transmission medium 201 and a conversion core 200 having a distribution of a plurality of phosphor particles 202 in a non-uniform volumetric suspension within the conversion core 200. In one embodiment, the manufacturing process for suspending the plurality of phosphor particles 202 may require mixing the plurality of phosphor particles 202 with a carrier material such as, for example, polymethyl methacrylate (PMMA). Other carrier materials may be used, such as other optical polymers, ceramics, polyesters, polystyrenes, polycarbonates, polyethylenes, polyurethanes, olefins, copolymers, gels, hydrogels, vitreous materials, crystalline materials, supercooled liquids, and other similar materials including materials having the ability to act as carriers for phosphor particles having similar properties and characteristics described but not recited herein. The carrier material may comprise a transmission medium 201 within which the plurality of phosphor particles 202 are suspended. The resulting mixture of the carrier material and the plurality of phosphor particles 202 may be compressed and extruded into individual sub-layers that are compressed, adhered, and / or joined to form the conversion core 200. The plurality of phosphor particles 202 and the carrier material, such as PMMA or a ceramic material, for example, may be varied and controlled for each thin sub-layer or group of layers that are further joined to additional layers of the integrally mixed PMMA or ceramic and phosphor particles 202 to achieve the desired proportion of the plurality of phosphor particles 202.

[0036] Referring to FIG. 2A, in some embodiments, the conversion core 200 is optionally coupled to a light source 232 that emits light 204 that may have a first emission spectrum. The conversion core 200 can be used within the device 230. The device 230 can be, for example, a wireless imaging device as disclosed in U.S. Patent No. 10,610,089, which is hereby incorporated by reference in its entirety. The device 230 may further include an optical element 233, a light reflector 235, a package 231, and a filter 237. The light source 232 of the device 230 may output light 204 that interacts with the conversion core 200 to output converted light 206. The device 230 may include an optical element 233 that can be disposed between the light source 232 and the conversion core 200. The optical element 233 can redirect the light 204 toward the conversion core 200. The device 230 may include a light reflector 235 and a filter configured to further condition the converted light 206 converted by the conversion core 200. The light source 232 may be disposed anywhere as long as the light 204 that interacts with the plurality of phosphor particles 202 is perpendicular to the layer of the conversion core 200.

[0037] Referring to FIG. 2B, the conversion core 200 may have a distal end 226, a proximal end 228, and a length L extending between the proximal end 228 and the distal end 226. The dimensions of the conversion core 200 may be in the range of millimeters to meters. In some embodiments, the conversion core 200 has dimensions of several millimeters, several centimeters, several decimeters, or several meters. For example, the conversion core 200 may have a length L of 10 mm, a width of 5 mm, and a height of 5 mm. The conversion core 200 may have a length L of 1 mm to 50 mm, 5 mm to 40 mm, 10 mm to 30 mm, or 20 mm to 25 mm. The conversion core 200 may have a width of 1 mm to 50 mm, 5 mm to 40 mm, 10 mm to 30 mm, or 20 mm to 25 mm. The conversion core 200 may have a height of 1 mm to 50 mm, 5 mm to 40 mm, 10 mm to 30 mm, or 20 mm to 25 mm. In one embodiment, the conversion core 200 is a cylinder having a length L of 10 mm and a diameter of 5 mm. In other examples, the conversion core 200 has a length L of more than 1 m, such as an elongated lighting tube.

[0038] Light 204 may enter the conversion core 200 from the proximal end 228. In one embodiment, the light 204 interacts with the phosphor particles 202 that convert the light 204 into converted light 206, and as a result, the converted light 206 is emitted from the conversion core 200. The converted light 206 may have a second emission spectrum different from the first emission spectrum of the light 204. The converted light 206 emitted from the conversion core 200 may be shown curved to represent different wavelengths after the interaction. For example, the light 204 may emit converted light 206 having a wavelength different from that of the light 204 by interacting with a plurality of phosphor particles 202. In other embodiments, the light 204 persists through the conversion core 200 without interacting with the plurality of phosphor particles 202, and as a result, unconverted light 208 is emitted from the conversion core 200. The unconverted light 208 may be light that does not interact with any of the phosphor particles 202, and as a result, the unconverted light 208 has the same wavelength as the light 204. In some embodiments, the wavelength of the unconverted light 208 is the same as the wavelength of the light 204.

[0039] The conversion core 200 may generate a mixture of converted light 206 and unconverted light 208. In some embodiments, the distribution of the phosphor particles 202 may be volumetrically suspended within the transmission medium 201 and arranged in a series of sub-layers. The plurality of phosphor particles 202 may be spaced apart from each other generally evenly across each cross-section along the length L of the conversion core 200. In one embodiment, the plurality of phosphor particles 202 may be evenly spaced apart from each other across each cross-section along the length L of the conversion core 200. In some embodiments, the plurality of phosphor particles 202 may be spaced apart from each other generally uniformly across each cross-section along the length L of the conversion core 200, where uniform means that the average spacing between the plurality of phosphor particles 202 is equal. In some embodiments, about 97%, 95%, 90%, 80%, 85%, or 75% of the plurality of phosphor particles 202 may be uniformly spaced apart from each other across each cross-section along the length L of the conversion core 200. In other embodiments, the plurality of phosphor particles 202 may be unevenly spaced apart from each other across each cross-section along the length L of the conversion core 200. For example, some of the plurality of phosphor particles 202 may be in clusters or groups within a layer or sub-layer, such that sub-groups of the plurality of phosphor particles 202 are unevenly spaced. About 97%, about 95%, about 90%, about 80%, about 85%, or about 75% of the plurality of phosphor particles 202 may be evenly spaced apart from each other across each cross-section along the length L of the conversion core 200.

[0040] A series of sub-layers may be intentionally arranged in a layer or group of layers, each having a distribution of phosphor particles 202 disposed therein and configured to continuously spread the absorption of light 204 from a light source. In one embodiment, the series of sub-layers may be intentionally arranged to continuously spread the absorption of light 204 from a light source. The distribution of phosphor particles 202 floating within the transmission medium 201 may be non-uniform as indicated by a smaller proportion of phosphor particles 202 at the proximal end 228 compared to a larger proportion of phosphor particles 202 at the distal end 226 of the transmission medium 201. In some embodiments, the conversion core 200 includes a continuous increase in the density of phosphor particles 202 from the proximal end 228 to the density of phosphor particles 202 adjacent to the distal end 226. The rate of density increase may depend on the desired output illumination target. For example, the conversion core 200 may include various rates of density increase based on the desired luminance, color, and / or overall system efficiency. In one embodiment, the density, chemical properties, size, composition, and / or proportion of phosphor particles 202 near the distal end 226 of the conversion core 200 may be different from the density, chemical properties, composition, and / or proportion of phosphor particles 202 near the proximal end 228 of the conversion core 200.

[0041] The embodiments of FIGS. 2A and 2B may be comparable to the embodiments of FIGS. 3-7 as described herein. The light conversion process may occur by using the processes of fluorescence emission and Stokes shift in the gradient phosphor particles within the conversion core. The volumetric suspension of phosphor particles 202 may form a gradient phosphor core within the conversion core 200. In one embodiment, a particular intentional volumetric suspension of phosphor particles 202 causes more phosphor particles 202 to interact with the incident light 204 and participate in the light conversion. Each layer of the conversion core 200 may be arranged in a matrix configuration. By increasing the proportion of phosphor particles 202 participating in the light conversion process without increasing the exposure surface area to light 204, the system efficiency may be significantly increased, enabling a smaller sized conversion core 200.

[0042] In one embodiment, due to the arrangement, density, chemical properties, composition, and / or ratio of the phosphor particles 202 floating within the transmission medium 201, more phosphor particles 202 interact with the light 204 and participate in the light conversion. In some embodiments, the density or ratio of the phosphor particles 202 is defined by the actual amount of phosphor mixed into the PMMA solution or other specific carrier medium. Various combinations of chemical properties or compositions of the phosphor particles 202 may be used, each having its own ratio to the total solute in each sublayer to achieve the desired result.

[0043] In one embodiment, the plurality of phosphor particles 202 include two or more different ratios of phosphor particles 202 over the length L of the conversion core 200. The ratio of the phosphor particles 202 may be the actual incorporation ratio of the phosphor particles 202 in the PMMA (or other specific carrier medium) at a point along the optical path of the light 204 from the light source. The ratio of the phosphor particles 202 in the PMMA or other specific carrier medium is changed based on the desired output and can be different. In one embodiment, the two or more different ratios of the phosphor particles 202 over the length L of the conversion core 200 differ by about 0% to about 100%. For example, the two or more different ratios of the phosphor particles 202 over the entire length L of the conversion core 200 may differ by 0%, 5%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100%. In other embodiments, the two or more ratios of the phosphor particles 202 over the length L of the conversion core 200 differ by about 0.1% to about 25%. However, the two or more ratios of the phosphor particles 202 over the length L of the conversion core 200 may differ by about 0.01% to about 25%, about 5% to about 95%, about 10% to about 75%, or about 15% to about 50%. The two or more ratios of the phosphor particles 202 can be configured to continuously broaden the absorption of the light 204 from the light source. The different ratios of the phosphor particles 202 need not be distributed in a one-way concentration, such as, but not limited to, from low to high, from high to low, etc. For example, the ratio of the phosphor particles 202 may be about 5% at the proximal end 228 and about 15% at the distal end 226. However, the ratio of the phosphor particles 202 may be about 0% to about 100%, about 5% to about 90%, about 15% to about 80%, about 25% to about 70%, or about 35% to 60% at the proximal end 228, and about 0% to about 100%, about 5% to about 90%, about 15% to about 80%, about 25% to about 70%, or about 35% to 60% at the distal end 226.

[0044] In some embodiments, a plurality of phosphor particles 202 are disposed within the transmission medium 201 of the conversion core 200. The transmission medium 201 can be composed of a transparent or translucent material configured to allow light of a specific visible wavelength to pass through the transmission medium 201 without being blocked. The transmission medium 201 can be composed of polypropylene, glass, acrylic, ceramic, polycarbonate, or any other transparent material. For example, the transmission medium 201 can be composed of a transparent multilayer ceramic material. The properties of the transparent multilayer ceramic material can be changed to change the color of the converted light 206. For example, the thickness of the layers of the transparent multilayer ceramic material can be adjusted to generate white light. In some embodiments, the transparent multilayer ceramic material of the transmission medium 201 can be changed to adjust the properties of the converted light 206, AlON, Al2O3, Dy2O3, PR 3+ , ND 3+ , CR4 + , YB 3+ , Dy 3+ , Gd 3+ , and / or Ce 3+ including.

[0045] The transmission medium 201 may be a material in which phosphor particles 202 can be incorporated at various temperatures. The transmission medium 201 may be configured to modify the optical properties of light 204 from a light source, including diffusion, absorption, and / or redirection of light of a specific wavelength. The transmission medium 201 may be composed of a multilayer or composite material. In one embodiment, the thickness of each individual layer of the multiple layers of the transmission medium 201 ranges from about 30 microns to about 30 microns less than the total length of the conversion core 200. In other embodiments, the thickness of each individual layer of the multiple layers of the transmission medium ranges from about 0.01 mm to about 25 mm. The transmission mechanism of light 204 passing through the transmission medium 201 may be direct transmission, on-axis or off-axis, scattering, and / or specular reflection. Light 204 may be modified in several different ways, including color, luminance, average wavelength, peak wavelength, etc. For example, various optical elements may be used to modify light 204. In some embodiments, a lens is used to modify the properties of light 204. In some embodiments, the lens is not used within the light conversion system 20.

[0046] Referring to FIG. 3, a second exemplary embodiment is shown. In some embodiments, the light conversion system 30 is related to the light conversion system 20. The light conversion system 30 may include a distal end 326, a proximal end 328, a transmission medium 301, and a non-uniform conversion core 300 having phosphor particles 302 and 310. The conversion core 300 may include a left core 314 having a distribution of a plurality of phosphor particles 310, a right core 316 having a distribution of a plurality of phosphor particles 302, and an interfacial layer 312. The left core 314 and the right core 316 may be optically coupled to a light source that emits light 304. The interfacial layer 312 may be disposed between the left core 314 and the right core 316.

[0047] The transmission medium 301 of the optical conversion system 30 may be composed of layers, which may in turn be composed of individual sub-layers. For example, as shown in FIG. 3, the optical conversion system 30 may be composed of layer 318-1 and layer 318-2. Layer 318-N may refer to any one of the shown layers (e.g., layer 318-1, layer 318-2, etc.). Layer 318-1 may in turn be composed of individual sub-layers, sub-layer 320-N. Sub-layer 320-N may refer to any one of the shown individual sub-layers (e.g., sub-layer 320-1, sub-layer 320-2, sub-layer 320-3, sub-layer 320-4, sub-layer 320-5, and / or sub-layer 320-6). Similarly, layer 318-2 may also be composed of individual sub-layers (not shown). In one embodiment, layer 318-1 and layer 318-2 may each be composed of six individual sub-layers. The thickness of the individual sub-layer 320-N may be, for example, the diameter of one phosphor particle. Thus, the thickness of layer 318-N may be determined by the thickness of the individual sub-layer 320-N. For example, the thickness of layer 318-N may be the sum of the thicknesses of all sub-layers 320-N. As described above, by having phosphor particles 310 of similar density and composition in sub-layer 320-N within layer 318-1, specific control of the arrangement of phosphor particles 310 in each layer 318-N and in the transmission medium 301 may be possible. The specific arrangement of phosphor particles 310 may similarly be applicable to FIGS. 2B, 4-7, and 14A-14C.

[0048] In one embodiment, the light 304 may enter the transmission medium 301 of the conversion core 300 through the left core 314. The light 304 may interact well with the phosphor particles 310, 302, and as a result, the converted light 306 is emitted from the conversion core 300. The phosphor particles 302 volumetrically floating in the right core 316 may be intentionally arranged in a series of sub-layers. The series of sub-layers may be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of the light 304. Compared with FIGS. 1 and 2, FIG. 3 may show an increased level of optical conversion indicated by the converted light 306 emitted from the conversion core 300 and a decrease in the depiction of the unconverted light 308 emitted from the distal end 326 of the transmission medium 301. The decrease in the amount of the unconverted light 308 when compared with FIG. 1 may be due to the formation of the gradient phosphor core and / or a discontinuous increasing gradient in the density of the phosphor particles 310, 302.

[0049] In one embodiment, the distribution of the phosphor particles 302, 310 volumetrically floating in the left core 314 and the right core 316 is non-uniform. For example, a smaller proportion of the phosphor particles 310 may volumetrically float in the left core 314 compared to a large proportion of the phosphor particles 302 that may volumetrically float in the right core 316. In some embodiments, the conversion core 300 includes a discontinuous increasing gradient from the density of the phosphor particles 310 in the left core 314 to the density of the phosphor particles 302 in the right core 316. Also, at or adjacent to the layer interface 312, there may be a sharp increase in the density of the phosphor particles 302, 310.

[0050] In some embodiments, the volumetric suspension of phosphor particles 302, 310 forms a gradient within the transmission medium 301 of the conversion core 300. In one embodiment, the volumetric suspension of phosphor particles 302, 310 causes more phosphor particles 302, 310 to interact with the incident light 304 and participate in the light conversion. By increasing the proportion of phosphor particles 302, 310 participating in the light conversion process without increasing the exposure surface area to the incident light 304 and without requiring a dedicated optical system, the efficiency of the light conversion system 30 can be significantly increased while allowing a relatively small overall size. In one embodiment, due to the arrangement, density, chemical properties, composition, and / or proportion of the phosphor particles 302, 310 floating in the transmission medium 301, more phosphor particles 302, 310 interact with the light 304 and participate in the light conversion.

[0051] Referring to FIG. 4, a third exemplary embodiment of the present invention is shown. In some embodiments, the light conversion system 40 is related to the light conversion systems 20, 30. The light conversion system 40 may include a volumetric heterogeneous conversion core 400 having a distal end 426, a proximal end 428, a transmission medium 401, and phosphor particles 402, 410. The conversion core 400 may be composed of a left core 414, a left middle core 416, a right middle core 418, a right core 420, and layer interfaces 422, 412, and 424. The layer interface 422 may be disposed between the left core 414 and the left middle core 416. The layer interface 412 may be disposed between the left middle core 416 and the right middle core 418. The layer interface 424 may be disposed between the right middle core 418 and the right core 420.

[0052] Each of the left core 414, left middle core 416, right middle core 418, and right core 420 of the conversion core 400 can be distinguished by a specific density, composition, ratio, and / or chemical property of the phosphor particles 402, 410. The left core 414 may have a unique intentional distribution of a plurality of phosphor particles 410, and the right core 420 may have a unique intentional distribution of a plurality of phosphor particles 402. In some embodiments, the distribution of the plurality of phosphor particles 402 is different from the distribution of the plurality of phosphor particles 410. In other embodiments, the distribution of the plurality of phosphor particles 402 is the same as the distribution of the plurality of phosphor particles 410.

[0053] The transmission medium 401 can be optically coupled to a light source that emits light 404. The light 404 can enter the transmission medium 401 of the conversion core 400 from the left core 414. In one embodiment, the light 404 can interact with the phosphor particles 410, 402 throughout the conversion core 400, and as a result, the light 404 is converted into converted light 406 emitted from the conversion core 400. The distribution of the phosphor particles 410, 402 can be intentionally arranged in a series of sub-layers within the transmission medium 401. The series of sub-layers can be intentionally arranged in thicker layers or groups of layers configured to continuously spread the absorption of the light 404 from the light source. Compared to FIGS. 1 and 2B, FIG. 4 shows an increased level of light conversion. For example, FIG. 4 shows an increased amount of converted light 406 and no depiction of unconverted light emitted from the distal end 426 of the conversion core 400. This can be due to, for example, the formation of a gradient phosphor core and / or a discontinuous increasing gradient in the density of the phosphor particles 402, 410.

[0054] The distribution of the phosphor particles 402, 410 volumetrically floating within the transmission medium 401 of the conversion core 400 may be non-uniform as indicated by the relatively small proportion of the phosphor particles 410 in the left core 414 compared to the relatively large proportion of the phosphor particles 402 in the right core 420. There may be a discontinuous increasing gradient in the density of the phosphor particles 410 from the left core 414 through the left middle core 416 and the right middle core 418 to the right core 420. Also, at or adjacent to the layer interfaces 422, 412, and 424, there may be a sharp increase in the density of the phosphor particles 402, 410.

[0055] Referring to FIG. 5, a fourth exemplary embodiment of the present invention is shown. In some embodiments, the optical conversion system 50 is related to the optical conversion systems 20, 30, 40. The optical conversion system 50 may include a volumetrically non-uniform conversion core 500 having a distal end 526, a proximal end 528, a transmission medium 501, and phosphor particles 502, 510. The phosphor particles 502, 510 may be volumetrically disposed within the transmission medium 501 and may have a distribution of a plurality of phosphor particles 510 of a first type and a distribution of a plurality of phosphor particles 502 of a second type throughout the transmission medium 501. The conversion core 500 may be optically coupled to a light source that emits light 504 and may include a left core 514 and a right core 520. The light 504 may enter into the transmission medium 501 of the conversion core 500 from the left core 514. In one embodiment, the light 504 interacts with the phosphor particles 502, 510, and as a result, the light 504 is converted into converted light 506 and emitted from the conversion core 500.

[0056] The distribution of phosphor particles 502, 510 can be intentionally arranged in a series of sub-layers within the transmission medium 501. The series of sub-layers can be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of light 504. Compared with FIGS. 1 and 2B, FIG. 5 may show an increased level of light conversion indicated by the converted light 506 emitted from the conversion core 500, and may also show the absence of a depiction of light emitted from the distal end 526 of the conversion core 500. This can be due to, for example, the use of two different types of phosphor particles 502, 510, the formation of a gradient phosphor core, and / or a continuous increasing gradient in the density of phosphor particles 502, 510.

[0057] The distribution of phosphor particles 502, 510 volumetrically suspended within the conversion core 500 can be non-uniform, as indicated by a smaller proportion of the first type of phosphor particles 510 volumetrically suspended within the left core 514 of the conversion core 500 compared to a larger proportion of the second type of phosphor particles 502 volumetrically suspended within the right core 520 of the conversion core 500. There can be a continuous increasing gradient from the density of the first type of phosphor particles 510 adjacent to the proximal end 528 to the density of the second type of phosphor particles 502 adjacent to the distal end 526.

[0058] The volumetric suspension of phosphor particles 502, 510 can form a gradient phosphor core in the conversion core 500. In one embodiment, the volumetric suspension of phosphor particles 502, 510 allows more phosphor particles to interact with the light 504 and participate in the light conversion. By increasing the proportion of phosphor particles 502, 510 participating in the light conversion process without increasing the exposure surface area to the light 504, the efficiency of the light conversion system 50 can be significantly increased while allowing for a relatively small overall size for the light source for subsequent light output. In one embodiment, due to the arrangement, density, chemical properties, composition, and / or proportion of phosphor particles 502, 510 suspended within the transmission medium 501 of the conversion core 500, more phosphor particles 502, 510 can interact with the light 504 and participate in the light conversion.

[0059] Referring to FIG. 6, a fifth exemplary embodiment of the present invention is shown. In some embodiments, the optical conversion system 60 is related to the optical conversion systems 20, 30, 40, 50. The optical conversion system 60 may include a non-uniform conversion core 600 having a proximal end 262, a proximal end 628, a transmission medium 601, and phosphor particles 602, 610. The conversion core 600 may include a left core 614, a right core 616, a layer interface 612, a plurality of phosphor particles 610 of a first type dispersed within the left core 614, and a plurality of phosphor particles 602 of a second type dispersed within the right core 616. The conversion core 600 may be optically coupled to a light source that emits light 604. The light 604 may enter the transmission medium 601 of the conversion core 600 from the left core 614. In one embodiment, the light 604 may interact with the phosphor particles 602, 610, and as a result, converted light 606 is emitted from the conversion core 600.

[0060] The distribution of the phosphor particles 602, 610 may be intentionally arranged in a series of sub-layers in the transmission medium 601. The series of sub-layers may be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of the light 604. Compared to FIGS. 1 and 2B, FIG. 6 may show an increased level of optical conversion indicated by the converted light 606 emitted from the conversion core 600, and there is no depiction of light emitted from the distal end 626 of the conversion core 600. This may be due to, for example, the use of two different types of phosphor particles 602, 610, the formation of a gradient phosphor core, and / or a discontinuous increasing gradient in the density of the phosphor particles 602, 610.

[0061] The distribution of the phosphor particles 602, 610 volumetrically floating within the conversion core 600 may be non-uniform, as indicated by the fact that the proportion of the first type of phosphor particles 610 volumetrically floating within the left core 614 of the conversion core 600 is smaller compared to the large proportion of the second type of phosphor particles 602 volumetrically floating within the right core 616 of the conversion core 600. There may be a discontinuous increasing gradient from the density of the first type of phosphor particles 610 at the proximal end 628 to the density of the second type of phosphor particles 602 adjacent to the distal end 626. Also, there may be a sharp increase in the density of the phosphor particles 602, 610 at the layer interface 612.

[0062] Referring to FIG. 7, a sixth exemplary embodiment of the present invention is shown. In some embodiments, the light conversion system 70 is related to the light conversion systems 20, 30, 40, 50, 60. The light conversion system 70 may include a conversion core 700 having a proximal end 732, a distal end 730, a transmission medium 701, and phosphor particles 702, 710, 728, 726. The conversion core 700 may include a left core 714 having a first type of phosphor particles 710, a left middle core 716 having a second type of phosphor particles 726, a right middle core 718 having a third type of phosphor particles 728, a right core 720 having a fourth type of phosphor particles, and layer interfaces 722, 712, and 724. The layer interface 722 may be disposed between the left core 714 and the left middle core 716. The layer interface 712 may be disposed between the left middle core 716 and the right middle core 718. The layer interface 724 may be disposed between the right middle core 718 and the right core 720.

[0063] Each of the left core 714, left middle core 716, right middle core 718, and right core 720 of the conversion core 700 can be distinguished by a specific density, composition, ratio, and / or chemical property. The conversion core 700 can be optically coupled to a light source that emits light 704. The light 704 can enter the transmission medium 701 of the conversion core 700 from the left core 714. In one embodiment, the light 704 may interact with the phosphor particles 702, 726, 728, 710, and as a result, converted light 706 is emitted. The distribution of the phosphor particles 702, 726, 728, 710 can be intentionally arranged in a series of sub-layers within the transmission medium 701. The series of sub-layers can be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of the light 704. Compared with FIGS. 1 and 2B, FIG. 7 may show an increased level of optical conversion indicated by the converted light 706 emitted from the conversion core 700, and there is no depiction of unconverted light emitted from the distal end 730 of the conversion core 700. This can be due to, for example, the use of four different types of phosphor particles 702, 710, 726, 728, the formation of a gradient phosphor core, and / or a continuous increasing gradient in the density of the phosphor particles 702, 710, 726, 728.

[0064] The distribution of the phosphor particles 702, 710, 726, 728 volumetrically floating within the transmission medium 701 of the conversion core 700 may be non-uniform as shown by a smaller proportion of the first type of phosphor particles 710 volumetrically floating within the left core 714 of the conversion core 700 compared to a larger proportion of the fourth type of phosphor particles 702 volumetrically floating within the right core 720 of the conversion core 700. There may be a discontinuous increasing gradient in the density of the first type of phosphor particles 710 in the left core 714 through the left middle core 716 having the second type of phosphor particles 726 and the right middle core 718 having the third type of phosphor particles 728 to the density of the fourth type of phosphor particles 702 adjacent to the right core 720. Also, there may be a sharp increase in the phosphor particles 702, 710, 726, 728 at the layer interfaces 712, 722, and 724.

[0065] Referring to FIG. 8, a graph showing the relationship between the density of phosphor particles dispersed throughout the transmission medium and the length of the volumetric phosphor conversion core is shown. The density can increase with a single discontinuous non-linear gradient. This discontinuous increase can be shown by a step graph.

[0066] Referring to FIG. 9, a graph showing the relationship between the density of phosphor particles dispersed throughout the transmission medium and the length of the volumetric phosphor conversion core is shown, and the density can increase with a single continuous non-linear gradient.

[0067] Referring to FIG. 10, a graph showing the relationship between the density of phosphor particles dispersed throughout the transmission medium and the length of the volumetric phosphor conversion core is shown, and the density can increase with multiple discontinuous non-linear gradients. This discontinuous increase can be shown by a step graph.

[0068] Referring to FIG. 11, a graph showing the relationship between the density of phosphor particles dispersed throughout the transmission medium and the length of the volumetric phosphor conversion core is shown, and the density can increase with multiple continuous non-linear gradients.

[0069] Referring to FIG. 12, a graph showing the relationship between the density of phosphor particles dispersed throughout the transmission medium and the length of the volumetric phosphor conversion core is shown, and the density can increase with a single continuous linear gradient.

[0070] Referring to FIG. 13, a schematic diagram of an optical conversion system showing a typical arrangement of layers and sub-layers is shown. For example, layer 1 1300-1 can be composed of individual sub-layers, layer 2 1300-2 can be composed of individual sub-layers, and layer 3 1300-3 can be composed of individual sub-layers. The individual sub-layers of each layer 1300-1, 1300-2, 1300-3 may have the same or identical phosphor particle density and composition. At a minimum, the thickness of the sub-layer may be the diameter of a single phosphor particle. However, the thickness of the sub-layer may be the diameter of two phosphor particles, three phosphor particles, four phosphor particles, or a number of phosphor particles greater than four. The thickness of the sub-layer depends on the optical conversion and modulation characteristics required for each use case. Each layer can be composed of dozens, hundreds, thousands, or millions of sub-layers.

[0071] Referring to FIGS. 14A - 14C, a schematic diagram of a light conversion system is shown, depicting a typical radial arrangement of phosphor particle density within a volumetric phosphor conversion core. In FIGS. 14A - 14C, a higher phosphor particle density may be represented by a denser shade. For example, in one embodiment in FIG. 14A, the phosphor particle distribution may be arranged such that individual layers have a gradient phosphor distribution 1401 where the density of phosphor particles increases radially outward from the center. In another embodiment in FIG. 14B, the individual layers may have a gradient phosphor distribution 1402 where the density of phosphor particles decreases radially outward from the center, or any other arbitrary arrangement that may be continuous or discontinuous with respect to the change in phosphor particle density. In yet another embodiment in FIG. 14C, these aforementioned radial layers may be arranged in a volumetric shape such as a cylinder 1403, and each radial layer may be different from the layers before and after. The volumetric shapes described herein are not limited to cylinders, and the radial layers may be used in volumetric shapes such as, but not limited to, prisms, cones, cubes, or any other solid geometry. The solid geometry constructed using these radial layers may have different densities throughout the radial direction 1404 and / or the axial direction 1405.

[0072] As will be understood by those skilled in the art, the typical embodiments shown and described above may be modified without departing from the broad inventive concept. Accordingly, it is understood that the present invention is not limited to the typical embodiments shown and described, and is intended to cover modifications within the spirit and scope of the present invention as defined by the claims. For example, specific features of a typical embodiment may or may not be part of the present invention, and various features of the disclosed embodiments may be combined. Unless specifically stated otherwise herein, the words "a", "an", and "the" should not be read as being limited to one element, but rather as intended to mean "at least one".

[0073] It should be understood that at least some of the figures and descriptions of the present invention are simplified to focus on elements relevant to a clear understanding of the present invention, and for clarity, other elements that a person skilled in the art would understand to constitute part of the present invention are removed. However, since such elements are well known in the art and do not necessarily lead to a proper understanding of the present invention, such elements are not described in this specification.

[0074] Also, if the method of the present invention does not depend on a specific order of the steps described herein, the specific order of the steps should not be construed as limiting the claims. Any claims directed to the method of the present invention should not be limited to the performance in the described order of those steps, and a person skilled in the art can easily understand that the steps can be changed while remaining within the gist and scope of the present invention.

Claims

1. a heterogeneous conversion core having a transmission medium configured with a plurality of layers, a proximal end, a distal end, and a length extending between the proximal end and the distal end, the heterogeneous conversion core optically coupled to a light source; a plurality of phosphor particles volumetrically suspended in each of the plurality of layers of the transmission medium, the density of the plurality of phosphor particles in one of the plurality of layers proximate the proximal end of the conversion core being different from the density of the plurality of phosphor particles in another one of the plurality of layers proximate the distal end of the transmission medium; A light source converter comprising:

2. The light source converter of claim 1 , wherein the plurality of phosphor particles comprises two or more phosphor particle proportions, compositions, sizes, and / or chemistries.

3. 3. The light source converter of claim 2, wherein the percentage of the two or more phosphor particles across the length of the transmission medium is between about 0% and about 100%.

4. 3. The light source converter of claim 2, wherein the percentage of the two or more phosphor particles across the length of the transmission medium is between about 0.1% and about 25%.

5. The light source converter of claim 1 , wherein the plurality of phosphor particles comprises two or more phosphor types.

6. 6. The light source converter of claim 5, wherein one or more of the proportion, chemistry, size, and composition of the two or more phosphor particles are configured to continuously widen an absorption band of light from the light source.

7. The light source converter of claim 1 , wherein the volumetric suspension of the plurality of phosphor particles forms a gradient phosphor core.

8. The light source converter of claim 7 , wherein the gradient phosphor core is a continuous or discontinuous gradient phosphor core.

9. 10. The light source converter of claim 1, wherein the thickness of each of the plurality of layers is from about 30 microns to about 30 microns less than the overall length of the transmission medium.

10. The light source converter of claim 1 , wherein the density of the plurality of phosphor particles increases or decreases from the proximal end to the distal end.

11. 10. The light source converter of claim 1, wherein the transmission medium is comprised of a translucent material or materials configured to allow light of specific visible wavelengths to pass unimpeded through the transmission medium.

12. 10. The light source transducer of claim 1, wherein the transmission medium is comprised of polypropylene, glass, acrylic, ceramic, polycarbonate, optical polymers, polyester, polystyrene, polyethylene, polyurethane, olefin, copolymers, gels, hydrogels, vitreous, crystalline, and / or supercooled liquids.

13. The light source transducer of claim 1 , wherein the transmission medium is comprised of polypropylene, glass, acrylic, ceramic, and / or polycarbonate.

14. 10. The light source converter of claim 1, wherein the conversion core is configured to modify optical properties of light from the light source by diffusing, absorbing, and / or redirecting light of specific wavelengths.

15. The light source converter of claim 1 , wherein each of the plurality of phosphor particles has a generally predetermined position within the plurality of layers.

16. 2. The light source converter of claim 1, wherein the plurality of phosphor particles are generally uniformly spaced from one another across each cross section along the length of the conversion core, each cross section being perpendicular to the length of the conversion core.

17. The light source converter of claim 1 , wherein the light source is a laser.

18. 10. The light source converter of claim 1, wherein each of said plurality of layers is comprised of multiple sublayers, each having the same phosphor particle density and / or phosphor particle chemistry within the sublayer.

19. 10. The light source converter of claim 1, wherein each of the plurality of layers has the same phosphor particle density and / or phosphor particle chemistry over the length of each of the plurality of layers.

20. 10. The light source converter of claim 1, wherein at least two of the plurality of layers differ in phosphor particle percentage, phosphor particle density, phosphor particle composition, phosphor particle size, and / or phosphor particle chemistry.

21. The light source converter of claim 1 , wherein each of the plurality of layers has a thickness of about 0.01 mm to about 25 mm.

22. The light source converter of claim 1 , wherein the volumetric suspension of the plurality of phosphor particles is a non-continuous volumetric suspension, including a non-linear, monotonic, or polytonic suspension.

23. 10. The light source converter of claim 1, wherein the light source outputs a first radiation spectrum and the converter core outputs a second radiation spectrum different from the first spectrum.

24. A laser light source; a heterogeneous conversion core optically coupled to the laser light source, the heterogeneous conversion core having a proximal end, a distal end, a length extending between the proximal end and the distal end, and a transmission medium constructed of a transparent or semi-transparent material or multiple materials and layers; a plurality of phosphor particles volumetrically suspended in each of the plurality of layers of the transmission medium, each layer being further arranged into a series of sublayers, each of the phosphor particles having a generally predetermined position within the series of sublayers and thicker layers or layer groups, a density of the plurality of phosphor particles adjacent the proximal end of the conversion core differing from a density of the plurality of phosphor particles adjacent the distal end of the conversion core to form a gradient phosphor core; Equipped with An optical device, wherein the gradient phosphor core is configured to continuously broaden and emit a spectrum of light absorption from the laser light source along the length of the conversion core.

Images