Light source converter

Abstract

A light source converter includes a heterogeneous conversion core optically coupled to a light source. The conversion core has a transmissive medium composed 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 also includes a plurality of phosphor particles that are suspended in volume in each of the plurality of layers of the transmissive medium. A density of the plurality of phosphor particles in one of the plurality of layers near the proximal end of the conversion core is different from a density of the plurality of phosphor particles in another of the plurality of layers near the distal end of the transmissive medium.

Description

[0001] This application is a divisional application, and the invention name of its parent application is "Light Source Converter", the application date is April 16, 2020, and the application number is 202080023171.X.

[0002] Cross - reference to related applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 834,677, entitled "Light Source Converter", filed on April 16, 2019, the entire content of which is incorporated herein by reference. Technical field

[0003] 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 art

[0004] Since the invention of the first solid - state lighting (SSL) devices in the 1920s, there has been a concentrated push to use them as alternatives to contemporary light sources. In the 1960s, the first bright SSL devices were invented, and their use as light sources increased sharply in industrial and consumer applications. The next major goal in SSL device research was to find a new way to produce white light, and this was mainly achieved by mixing narrow - band red, blue, and green (RGB) light sources. Compared to the expected broad - spectrum 'white' light, this mixing brought many problems, such as color accuracy and temperature reproduction.

[0005] The next stage in the development of SSL devices occurred in the 1990s, when bright blue light - emitting diodes (LEDs) were invented and subsequently combined with a thin layer of phosphor coating. This phosphor coating layer can interact with the blue light emitted from the diode and subsequently convert the light into a broad - spectrum emission, whose peak is at a wavelength longer than that of the incident blue light. Compared to the previous discrete RGB mixing method, the mixing of un - converted blue light and converted light can better reproduce broad - spectrum 'white' light.

[0006] Lasers emit light through optical amplification based on stimulated emission of electromagnetic radiation. Lasers are typically distinguished from other light sources by their spatial coherence. Spatial coherence is usually represented by the output of a laser being a narrow beam, which is diffraction - limited. Lasers also have temporal coherence, which enables them to emit light of a narrow spectrum and thus emit light of a single color. Lasers have long been used in situations where light with the desired spatial or temporal coherence may not be produced using simpler techniques.

[0007] Traditionally, the only way to make phosphor conversion function properly within an SSL device was to coat the light source in a thin layer of phosphor material. Subsequent research has shown that a large percentage of the incident blue light is reflected by the phosphor coating and is thus not converted, resulting in a significant loss of available light and a reduction in overall efficiency. In response to this, remote phosphors were developed, which is a method of offsetting the phosphor conversion material a certain distance from the light source. By placing the conversion material at a short distance from the light source, the likelihood of misreflection is reduced, and a higher conversion efficiency is achieved by an otherwise identical SSL device. Remote phosphors are typically lenses or caps made of a transparent medium that is coated with a very thin layer of phosphor and positioned away from the light source.

[0008] While remote phosphors are an improvement over older SSL devices in which the light source is directly covered in phosphor, using a thin layer of conversion material can present several problems. These problems may include: limitations on the amount of emitted light that can be converted before phosphor saturation, a direct correlation between the surface area of the emission source and the amount of phosphor that can be exposed, temperature concentration on the thin surface, and the overall efficiency of the conversion system.

[0009] Accordingly, there is a need for a light converter that can effectively convert a large amount of emitted light into light of a different wavelength SUMMARY OF THE INVENTION

[0010] In one embodiment, there is a light source converter that includes a heterogeneous conversion core optically coupled to a light source. The conversion core has a transmissive medium composed of multiple layers, a proximal end, a distal end, and a length extending between the proximal end and the distal end. The light source converter also includes a plurality of phosphor particles volumetrically suspended in each of the multiple layers of the transmissive medium, and the density of the plurality of phosphor particles in one layer near the proximal end of the conversion core is different from the density of the plurality of phosphor particles in another layer near the distal end of the transmissive medium.

[0011] In one embodiment, the plurality of phosphor particles includes two or more phosphor particle percentages, compositions, and / or chemical components. The two or more phosphor particle percentages across the length of the transmissive medium can range from about 0% to about 100% or from about 0.1% to about 25%.

[0012] In one embodiment, the plurality of phosphor particles includes two or more phosphor types. One or more of the percentages, chemical components, and compositions of the two or more phosphor particles can be configured to continuously broaden the absorption band of light from the light source.

[0013] In one embodiment, a volume suspension of a plurality of phosphor particles forms a gradient phosphor core. The gradient phosphor core can be a continuous or discontinuous gradient phosphor core.

[0014] In one embodiment, the thickness of each of the plurality of layers is from about 30 micrometers to about 30 micrometers less than the total length of the transmissive medium. The thickness of each of the plurality of layers can be from about 0.01 mm to about 25 mm.

[0015] In one embodiment, the density of the plurality of phosphor particles increases or decreases from the proximal end to the distal end.

[0016] In one embodiment, the transmissive medium is composed of a translucent material configured to allow light of certain visible wavelengths to pass through the transmissive medium unimpeded. The transmissive medium can be composed of polypropylene, glass, acrylic, ceramic, polycarbonate, optical polymer, polyester, polystyrene, polyethylene, polyurethane, olefin, copolymer, gel, hydrogel, vitreous body, crystal, and / or supercooled liquid.

[0017] In one embodiment, the transmissive medium is composed of polypropylene, glass, acrylic, ceramic, and / or polycarbonate.

[0018] In one embodiment, the conversion core is configured to modify the optical properties of light from a light source by diffusing, absorbing, and / or redirecting light of a specific wavelength.

[0019] 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 can be spaced apart from each other generally equidistantly across each cross-section along the length of the conversion core, where each cross-section is taken normal to the length of the conversion core.

[0020] In one embodiment, each of the plurality of layers is composed of a plurality of sub-layers, each sub-layer having the same phosphor particle density and / or phosphor particle chemical composition within the sub-layer. Each of the plurality of layers can have the same phosphor particle density and / or phosphor particle chemical composition across the length of each of the plurality of layers.

[0021] In one embodiment, the light source is a laser. The light source can output a first radiation spectrum and the conversion core can output a second radiation spectrum different from the first spectrum.

[0022] In one embodiment, at least two of the plurality of layers differ in terms of phosphor particle percentage, phosphor particle density, phosphor particle composition, and / or phosphor particle chemical composition.

[0023] In one embodiment, the volume suspension of the plurality of phosphor particles is a discontinuous volume suspension including non-linear, monotonic, or multi-tonic suspension.

[0024] Another embodiment of the present invention provides an optical device including a laser light source. The optical device may include a heterogeneous 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 further arranged in a series of sub-layers, each of the phosphor particles having a substantially predetermined position in the series of sub-layers and in a thicker layer or group of layers, the density of the plurality of phosphor particles near the proximal end of the conversion core being different from the density of the plurality of phosphor particles near the distal end of the conversion core to form 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The foregoing summary of the invention, as well as the following detailed description of embodiments of the light source converter, will be better understood when read in conjunction with the accompanying drawings of exemplary embodiments. However, it is to be understood that the invention is not limited to the precise arrangements and instrumentalities shown.

[0026] FIG. 1 is a schematic diagram of a prior art light source converter having a homogeneous volume phosphor conversion core; Figure 2A FIG. is a schematic diagram of a light source having a light source converter according to an exemplary embodiment of the present invention, the light source converter having a volume phosphor conversion core and a continuous density gradient; Figure 2B FIG. is a schematic diagram of a light source converter according to an exemplary embodiment of the present invention, the light source converter having a volume phosphor conversion core and a continuous density gradient; Figure 3 FIG. is a schematic diagram of a light source converter according to an exemplary embodiment of the present invention, the light source converter having a volume phosphor conversion core and a discontinuous density gradient; Figure 4 FIG. is a schematic diagram of a light source converter according to an exemplary embodiment of the present invention, the light source converter having a volume phosphor conversion core and a discontinuous density gradient; Figure 5 FIG. is a schematic diagram of a light source converter according to an exemplary embodiment of the present invention, the light source converter having a volume phosphor conversion core and a continuous density gradient, having two different phosphor types; Figure 6 FIG. is a schematic diagram of a light source converter according to an exemplary embodiment of the present invention, the light source converter having a volume phosphor conversion core and a discontinuous density gradient, having two different phosphor types; Figure 7 FIG. 1 is a schematic view of a light source converter according to an exemplary embodiment of the present invention, in which phosphor particles are intentionally distributed in a series of layers in a transmission medium, and the density of the particles increases in a discontinuous gradient from the left side to the right side of the transmission medium and the non-uniform gradient volume phosphor conversion core (and the type of phosphor also changes in four stages from the left side to the right side of the transmission medium); Figure 8 FIG. 2 is a diagram showing the density of phosphor particles distributed throughout the transmission medium along the y-axis and the length of the volume phosphor conversion core along the x-axis according to an exemplary embodiment of the present invention; Figure 9 FIG. 3 is a diagram showing the density of phosphor particles distributed throughout the transmission medium along the y-axis and the length of the volume phosphor conversion core along the x-axis according to an exemplary embodiment of the present invention; Figure 10 FIG. 4 is a diagram showing the density of phosphor particles distributed throughout the transmission medium along the y-axis and the length of the volume phosphor conversion core along the x-axis according to an exemplary embodiment of the present invention; Figure 11 FIG. 5 is a diagram showing the density of phosphor particles distributed throughout the transmission medium along the y-axis and the length of the volume phosphor conversion core along the x-axis according to an exemplary embodiment of the present invention; Figure 12 FIG. 6 is a diagram showing the density of phosphor particles distributed throughout the transmission medium along the y-axis and the length of the volume phosphor conversion core along the x-axis according to an exemplary embodiment of the present invention; Figure 13 FIG. 7 is a schematic view of a light source converter, which shows the arrangement of layers and sub-layers; Figure 14A FIG. 8 is a schematic view of a light source converter, which shows an exemplary radial arrangement of the density of phosphor particles within a volume phosphor conversion core; Figure 14B FIG. 9 is a schematic view of a light source converter, which shows an exemplary radial arrangement of the density of phosphor particles within a volume phosphor conversion core; and Figure 14C FIG. 10 is a schematic view of a light source converter, which shows an exemplary radial arrangement of the density of phosphor particles within a volume phosphor conversion core. DETAILED DESCRIPTION

[0027] Embodiments of the present invention can provide a method for volumetrically disposing phosphor compounds in a host medium, where the volume percentage of the phosphor can vary. Compared to current systems that use thin, uniformly distributed coatings on remote surfaces, the benefits of a volumetric gradient phosphor core are numerous and are described herein. The benefits of a volumetric phosphor core may be that a greater volume of phosphor compound can be exposed to incident light without using dedicated optics. A greater amount of phosphor can be used in the conversion process without increasing the surface area exposed to incident light, which can significantly improve the efficiency of the system while allowing for a relatively small overall size of the light source for subsequent light output.

[0028] Compared to current thin coating methods, the advantage is the gradient distribution of the phosphor compound within the host medium. Using a gradient distribution can allow for more precise control of the characteristics of the converted output light. The precise control caused by the gradient distribution can contribute to various aspects of the output light, such as but not limited to better color reproduction, more controllable color temperature, more controllable peak wavelength, better temperature handling, better mixing of narrowband incident light and broadband emitted light, a more temperature-stable system, and a more efficient conversion process.

[0029] Embodiments of the present invention can provide a stepped (discontinuous) gradient distribution or a smooth (continuous) gradient distribution of phosphor material within the host medium. Such distributions can be, but are not limited to, linear, non-linear, monotonic, multi-tonic, etc. The gradient distribution can also constitute a variation in the thickness of the distribution layer, which ranges from, for example but not limited to, 30 microns to 30 microns less than the length of the entire core. This type of gradient can be achieved through a manufacturing process that produces layers. Each layer can be composed of multiple sub-layers. Each sub-layer can be composed of a similar or identical phosphor particle density and composition. The manufacturing process can produce and combine layers by a variety of methods, such as but not limited to lamination, hydrothermal synthesis, sintering, fusion, deposition, sol-gel processes, gel combustion, diffusion bonding, chemical precipitation, co-precipitation, solid-state / wet chemical synthesis, and / or adhesives.

[0030] The manufacturing process can also allow for the intentional use of multiple phosphor compounds, multiple phosphor particle sizes, and different phosphor compounds distributed at different concentrations within the same phosphor core. This can result in even more precise control of the converted output light. The manufacturing process also involves the intentional selection of the percentage, size, and type of phosphors to be suspended in the transmissive medium to ensure that the output light meets the requirements of each use case. The manufacturing process also allows for a series of thin sub-layers of the carrier medium (now mixed with phosphor particles at a predetermined percentage) to be intentionally arranged into thicker layers or groups of layers, resulting in more precise light output. The individual sub-layers can have similar or identical phosphor particle densities, sizes, and / or compositions between the sub-layers within each layer. Having similar phosphor particle densities and compositions within the sub-layers of each layer can allow for specific control of the phosphor particle arrangement within the corresponding layer and the entire transmissive medium. At a minimum, the thickness of the sub-layer can be the diameter of a single phosphor particle. The thickness of the sub-layer depends on the light conversion and modulation properties required for each use case. Each layer can be composed of dozens, hundreds, thousands, or millions of sub-layers. Throughout the process, an optimized workflow is established, which is based on rigorously tested observations and continuously improves the efficiency of phosphor particle suspension and the control thereof.

[0031] Embodiments of the present invention can be a heterogeneous gradient volume phosphor conversion core, where the lowest concentration of phosphors can be located on the side where the incident light enters the conversion core, and the highest concentration of phosphors can be located at the distal end of the side where the incident light enters the conversion core. Another embodiment of the present invention can be a heterogeneous gradient volume phosphor conversion core, where the lowest and highest concentrations of phosphors can be located within the conversion core, but not necessarily oriented from the lowest concentration to the highest concentration with respect to the incident light. Such an embodiment of the present invention can be a heterogeneous gradient volume phosphor conversion core, where the lowest and highest concentrations of phosphors can be located within the conversion core, and the concentration of the phosphors can vary in a radial distribution from the central axis of the core. For example, such an embodiment can have the highest concentration at the center and decrease radially outward within the core. For example, another such embodiment can have the lowest concentration at the center and increase radially outward.

[0032] The present invention can relate to an improved method for effectively converting narrowband light into broadband light of a longer wavelength. For example, narrowband blue light with a peak wavelength of 450 nm can be converted into broadband light ranging from 450 nm to 750 nm. In a second example, narrowband green light with a peak wavelength of 515 nm can be converted into broadband light ranging from 900 nm to 3 microns. As described below, in some embodiments, gradient volume phosphor conversion cores have been developed.

[0033] Referring to FIG. 1, a conventional method for light conversion disclosed in the prior art is shown. The light conversion system 10 may include a conversion core 100 having a transmissive medium 101 and a distribution of phosphor particles 102 distributed throughout the volume of the transmissive medium 101. A light source (not shown) may be optically coupled to the transmissive medium 101 and may be configured to emit light 104, wherein the light 104 may enter and transmit through the conversion core 100.

[0034] In one embodiment, the light source is a laser for the conversion process and having an output wavelength of 450 nm and a light power output of 100 mW. In another embodiment, the light source is a laser for the conversion process and having an output wavelength of 515 nm and a light power output of 150 mW. In yet another embodiment, the light source is a laser for the conversion process and having an output wavelength of 445 nm and a light power output of 10 W. However, the laser source may have a wavelength suitable for exciting a specifically defined phosphor material and may be, for example but not limited to, laser radiation having a wavelength between 200 nm and 450 nm, between 400 nm and 750 mm, between 450 nm and 900 nm, between 800 nm and 1550 nm, etc.

[0035] In the method shown in FIG. 1, a homogeneous distribution of phosphor particles 102 may exist throughout the volume of the entire conversion core 100. In addition, this homogeneous distribution of phosphor particles 102 may be arranged in a random and unintentional manner such that the input beam 104 may not be configured to interact with the phosphor particles 102 to maximize light conversion. In one embodiment, the input beam 104 interacts with the phosphor particles 102, thereby causing the emission of converted light 106. In another embodiment, the light 104 does not interact with the phosphor particles 102, thereby causing the emission of unconverted light 108. This random and unintentional particle arrangement may also require the use of dedicated optics to focus the light into the transmissive medium. The conversion core 100 may also need to be positioned at a short distance from the light source to reduce the likelihood of reflection.

[0036] Reference Figure 2A and Figure 2B, showing a first exemplary embodiment of the present invention. In one embodiment, there is a light conversion system 20, which includes a conversion core 200 having a transmissive medium 201 and a distribution of a plurality of phosphor particles 202 heterogeneously suspended within the conversion core 200. In one embodiment, the manufacturing process of suspending the plurality of phosphor particles 202 may require mixing the plurality of phosphor particles 202 with a carrier material such as 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 bodies, crystals, supercooled liquids, and other similar materials, including those not specified but having similar properties and the ability to act as carriers for the phosphor particles with the described characteristics. The carrier material may include the transmissive medium 201 in 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, and then the individual sub-layers are compressed, glued, and / or bonded to form the 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 the desired percentage of the plurality of phosphor particles 202 in each thin sub-layer or group of layers, which are then further combined with additional layers of PMMA or ceramic and phosphor particles 202 mixed together.

[0037] Reference Figure 2A , in some embodiments, the conversion core 200 is optically coupled to a light source 232 that emits light 204 that may have a first radiation spectrum. The conversion core 200 may be used within a device 230. The device 230 may be a wireless imaging device, such as that disclosed in U.S. Patent No. 10,610,089, the entire content of which is incorporated herein by reference. The device 230 may further include an optical element 233, an optical 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 may be disposed between the light source 232 and the conversion core 200. The optical element 233 may redirect the light 204 to the conversion core 200. The device 230 may include an optical reflector 235 and a filter that may be configured to further condition the converted light 206 converted by the conversion core 200. The light source 232 may be positioned anywhere as long as the light 204 that interacts with the plurality of phosphor particles 202 is perpendicular to the layers of the conversion core 200.

[0038] Reference Figure 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 size of the conversion core 200 may be in the range of millimeters to meters. In some embodiments, the conversion core 200 has dimensions in millimeters, centimeters, decimeters, or 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 between 1 mm and 50 mm, between 5 mm and 40 mm, between 10 mm and 30 mm, or between 20 mm and 25 mm. The conversion core 200 may have a width between 1 mm and 50 mm, between 5 mm and 40 mm, between 10 mm and 30 mm, or between 20 mm and 25 mm. The conversion core 200 may have a height between 1 mm and 50 mm, between 5 mm and 40 mm, between 10 mm and 30 mm, or between 20 mm and 25 mm. In one embodiment, the conversion core 200 is a cylinder with a length L of 10 mm and a diameter of 5 mm. In other examples, the conversion core 200 has a length L greater than 1 m, such as an elongated light emitting tube.

[0039] 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, which convert the light 204 into converted light 206, thereby causing the converted light 206 to be emitted from the conversion core 200. The converted light 206 may have a second radiation spectrum different from the first radiation spectrum of the light 204. The converted light 206 emitted from the conversion core 200 may be shown as curved to represent different wavelengths after the interaction. For example, the light 204 may interact with a plurality of phosphor particles 202, thereby emitting converted light 206 having a wavelength different from that of the light 204. In another embodiment, the light 204 continues to pass through the conversion core 200 without interacting with the plurality of phosphor particles 202, thereby causing unconverted light 208 to be 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 thus causes the unconverted light 208 to have 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.

[0040] The conversion core 200 can produce a mixture of converted light 206 and unconverted light 208. In some embodiments, phosphor particles 202 are suspended in a volume of a transmissive medium 201, which can be arranged in a series of sub-layers. The plurality of phosphor particles 202 can be spaced apart from each other approximately equidistantly across each cross-section taken along the length L of the conversion core 200. In one embodiment, the plurality of phosphor particles 202 are spaced apart from each other equidistantly across each cross-section taken along the length L of the conversion core 200. In some embodiments, the plurality of phosphor particles 202 can be spaced apart from each other approximately uniformly across each cross-section taken along the length L of the conversion core 200, where uniformly means that the average spacing between the plurality of phosphor particles 202 is equal. In some embodiments, approximately 97%, 95%, 90%, 80%, 85%, or 75% of the plurality of phosphor particles 202 can be spaced apart from each other uniformly across each cross-section along the length L of the conversion core 200. In other embodiments, the plurality of phosphor particles 202 are spaced apart from each other non-equidistantly across each cross-section taken along the length L of the conversion core 200. For example, some of the plurality of phosphor particles 202 can agglomerate or group within a layer or sub-layer, causing sub-groups of the plurality of phosphor particles 202 to be spaced apart non-equidistantly. Approximately 97%, approximately 95%, approximately 90%, approximately 80%, approximately 85%, or approximately 75% of the plurality of phosphor particles 202 can be spaced apart from each other equidistantly across each cross-section taken along the length L of the conversion core 200.

[0041] The series of sub-layers can be intentionally arranged in multiple layers or groups of layers, each layer or group of layers having a distribution of phosphor particles 202 disposed therein and configured to continuously broaden the absorption of light 204 from a light source. In one embodiment, the series of sub-layers can be intentionally arranged to continuously broaden the absorption of light 204 from a light source. The distribution of phosphor particles 202 suspended in the transmissive medium 201 can be non-uniform, as shown, with a smaller percentage of phosphor particles 202 located on the proximal end 228 of the transmissive medium 201 and a larger percentage of phosphor particles 202 located on the distal end 226 of the transmissive 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 can depend on the desired target of the output illumination. For example, the conversion core 200 can include different rates of density increase based on the desired brightness, color, and / or efficiency of the overall system. In one embodiment, the density, chemical composition, size, composition, and / or percentage of phosphor particles 202 near the distal end 226 of the conversion core 200 can be different from the density, chemical composition, composition, and / or percentage of phosphor particles 202 near the proximal end 228 of the conversion core 200.

[0042] As described herein, Figure 2A and Figure 2B embodiments of Figures 3 to 7 can be compared to embodiments of. The light conversion process can occur by taking advantage of the process of fluorescence and Stokes shift in the gradient phosphor particles in the conversion core. The volumetric suspension of phosphor particles 202 can form a gradient phosphor core within the conversion core 200. In one embodiment, a specific and intentional volumetric suspension of phosphor particles 202 can cause more phosphor particles 202 to interact with the incident light 204 and participate in the light conversion. Each layer of the conversion core 200 can 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 the light 204 can significantly increase the efficiency of the system, thereby allowing the conversion core 200 to have a smaller size.

[0043] In one embodiment, the arrangement, density, chemical composition, composition, and / or percentage of phosphor particles 202 suspended in the transmission medium 201 cause more phosphor particles 202 to interact with the light 204 and participate in the light conversion. In some embodiments, the density or percentage of phosphor particles 202 is defined by the amount of actual phosphor mixed into a PMMA solution or another specified carrier medium. Combinations of different chemical compositions or compositions of phosphor particles 202 can be used, each having their own total solute percentage in each sublayer to achieve the desired result.

[0044] In one embodiment, the plurality of phosphor particles 202 include two or more different percentages of the length L of the phosphor particles 202 of the conversion core 200. The percentage of the phosphor particles 202 can be the actual mixing percentage of the phosphor particles 202 within the PMMA (or another specified carrier medium) at a point along the optical path of the light 204 from the light source. The percentage of the phosphor particles 202 within the PMMA or another specified carrier medium can vary and change based on the desired output. In one embodiment, the two or more different percentages of the phosphor particles 202 across the length L of the conversion core 200 vary from about 0% to about 100%. For example, the two or more different percentages of the phosphor particles 202 across the length L of the conversion core 200 can vary 0%, 5%, 10%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 90%, or 100%. In another embodiment, the two or more percentages of the phosphor particles 202 across the length L of the conversion core 200 vary from about 0.1% to about 25%. However, the two or more percentages of the phosphor particles 202 across the length L of the conversion core 200 can vary from about 0.01% to about 25%, from about 5% to about 95%, from about 10% to about 75%, or from about 15% to about 50%. The two or more percentages of the phosphor particles 202 can be configured to continuously broaden the absorption of the light 204 from the light source. The different percentages of the phosphor particles 202 need not be in an aligned concentration profile, such as but not limited to low to high, high to low, etc. For example, the percentage of the phosphor particles 202 can be about 5% at the proximal end 228 and 15% at the distal end 226. However, the percentage of the phosphor particles 202 can be between about 0% and about 100%, between about 5% and about 90%, between about 15% and about 80%, between about 25% and about 70%, or between about 35% and 60% at the proximal end 228, and can be between about 0% and about 100%, between about 5% and about 90%, between about 15% and about 80%, between about 25% and about 70%, or between about 35% and about 60% at the distal end 226.

[0045] In some embodiments, a plurality of phosphor particles 202 are disposed within a transmissive medium 201 of a conversion core 200. The transmissive medium 201 can be composed of a transparent or translucent material configured to allow light of a specified visible wavelength to pass through the transmissive medium 201 unimpeded. The transmissive medium 201 can be composed of polypropylene, glass, acrylic, ceramic, polycarbonate, or any other transparent material. For example, the transmissive medium 201 can be composed of a transparent multi-layer ceramic material. The properties of the transparent multi-layer ceramic material can be varied to change the color of the converted light 206. For example, the thickness of the layers of the transparent multi-layer ceramic material can be adjusted to produce white light. In some embodiments, the transparent multi-layer ceramic material of the transmissive medium 201 includes AlON, Al2O3, Dy2O3, PR 3+ , ND 3+ , CR4 + , YB 3+ , Dy 3+ , Gd 3+ and / or Ce 3+ , which can be varied to adjust the properties of the converted light 206.

[0046] The transmissive medium 201 can be a material in which the phosphor particles 202 can be mixed at varying temperatures. The transmissive medium 201 can be configured to modify the optical properties of light 204 from a light source, including diffusing, absorbing, and / or redirecting light of a specific wavelength. The transmissive medium 201 can be composed of multi-layers or hybrid materials. In one embodiment, the thickness of individual layers among the plurality of layers of the transmissive medium 201 ranges from about 30 microns to about 30 microns less than the length L of the conversion core 200. In another embodiment, the thickness of individual layers among the plurality of layers of the transmissive medium ranges from about 0.01 mm to about 25 mm. The transmission mechanism of light 204 through the transmissive medium 201 can be direct, coaxial or off-axis, scattered, and / or specular. Light 204 can be modified in several different ways, including color, brightness, average wavelength, peak wavelength, etc. For example, various optical elements can be used to modify light 204. In some embodiments, lenses are used to modify the properties of light 204. In some embodiments, no lenses are used within the light conversion system 20.

[0047] Reference Figure 3, showing a second exemplary embodiment. In some embodiments, the light conversion system 30 relates to the light conversion system 20. The light conversion system 30 may include a heterogeneous conversion core 300 having a distal end 326, a proximal end 328, a transmission medium 301, and 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 a layer interface 312. The left core 314 and the right core 316 may be optically coupled to a light source that emits light 304. The layer interface 312 may be disposed between the left core 314 and the right core 316.

[0048] The transmission medium 301 of the light conversion system 30 may be composed of layers, and the layers may be further composed of respective sub-layers. For example, as Figure 3 shown, the light conversion system 30 may be composed of layer 318-1 and layer 318-2. Layer 318-N may refer to any one of the depicted layers (e.g., layer 318-1, layer 318-2, etc.). Layer 318-1 may be further composed of respective sub-layers (sub-layers 320-N). Sub-layer 320-N may refer to any one of the depicted respective 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 respective sub-layers (not shown). In one embodiment, each of layer 318-1 and layer 318-2 may be composed of six individual sub-layers. The thickness of each sub-layer 320-N may be, for example, the diameter of a phosphor particle. Thus, the thickness of layer 318-N may be defined by the thickness of each 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, phosphor particles 310 having similar density and composition in sub-layers 320-N within layer 318-1 may allow specific control of the arrangement of phosphor particles 310 within the corresponding layer 318-N and the transmission medium 301. The specific arrangement of phosphor particles 310 may also be applicable to Figure 2B , Figures 4 to 7 and Figures 14A to 14C .

[0049] In one embodiment, light 304 may enter the transmission medium 301 of the conversion core 300 via the left core 314. Light 304 may interact with phosphor particles 310, 302, thereby causing the emission of converted light 306 from the conversion core 300. The distribution of phosphor particles 302 volume-suspended on 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 light 304. As compared with FIGS. 1 and 2, Figure 3An increase in the light conversion level depicted by the converted light 306 emitted from the conversion core 300 and a decrease in the light conversion level depicted from the unconverted light 308 emitted from the distal end 326 of the transmissive medium 301 may be shown. The decrease in the amount of the unconverted light 308 compared to FIG. 1 may be due to the formation of the gradient phosphor core and / or a discontinuous gradient increase in the density of the phosphor particles 310, 302.

[0050] In one embodiment, the distribution of the phosphor particles 302, 310 volumetrically suspended in the left core 314 and the right core 316 is heterogeneous. For example, a smaller percentage of the phosphor particles 310 may be volumetrically suspended in the left core 314, while a larger percentage of the phosphor particles 302 may be volumetrically suspended in the right core 316. In some embodiments, the conversion core 300 includes a discontinuous gradient increase in the density of the phosphor particles 310 from the left core 314 to the density of the phosphor particles 302 from the right core 316. Additionally, the density of the phosphor particles 302, 310 at or adjacent to the layer interface 312 may increase rapidly.

[0051] In some embodiments, the volumetric suspension of the phosphor particles 302, 310 in the transmissive medium 301 of the conversion core 300 forms a gradient. In one embodiment, the volumetric suspension of the phosphor particles 302, 310 causes more of the phosphor particles 302, 310 to interact with the incident light 304 and participate in light conversion. Increasing the percentage of the phosphor particles 302, 310 participating in the light conversion process without increasing the surface area exposed to the incident light 304 and also without requiring dedicated optics can significantly increase the efficiency of the light conversion system 30 while allowing for a relatively smaller overall size. In one embodiment, the arrangement, density, chemical composition, composition, and / or percentage of the phosphor particles 302, 310 suspended in the transmissive medium 301 causes more of the phosphor particles 302, 310 to interact with the light 304 and participate in light conversion.

[0052] Reference Figure 4 shows a third exemplary embodiment of the present invention. In some embodiments, the light conversion system 40 relates to the light conversion systems 20, 30. The light conversion system 40 may include a volumetrically heterogeneous conversion core 400 having a distal end 426, a proximal end 428, a transmissive 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.

[0053] 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 the specific density, composition, percentage, and / or chemical composition of the phosphor particles 402, 410. The left core 414 can have a unique and intentional distribution of a plurality of phosphor particles 410 and the right core 420 can have a 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 from the distribution of the plurality of phosphor particles 410. In another embodiment, the distribution of the plurality of phosphor particles 402 is the same as the distribution of the plurality of phosphor particles 410.

[0054] The transmissive medium 401 can be optically coupled to a light source that emits light 404. The light 404 can enter the transmissive 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, causing the light 404 to be converted into converted light 406, which is emitted from the conversion core 400. The distribution of the phosphor particles 410, 402 can be intentionally arranged in a series of sub-layers in the transmissive medium 401. The series of sub-layers can be intentionally arranged in thicker layers or groups of layers configured to continuously widen the absorption of the light 404 from the light source. As compared with FIG. 1 and Figure 2B compared to, Figure 4 depicts an increase in the light conversion level. For example, Figure 4 depicts an increase in the amount of the converted light 406 and no depiction of the 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 gradient increase in the density of the phosphor particles 402, 410.

[0055] The distribution of the phosphor particles 402, 410 volumetrically suspended in the transmissive medium 401 of the conversion core 400 may be heterogeneous, as shown, with a lower percentage of phosphor particles 410 in the left core 414 and a higher percentage of phosphor particles 402 in the right core 420. From the left core 414 through the left middle core 416, through the right middle core 418 to the right core 420, there may be a discontinuous gradient increase in the density of the phosphor particles 410. Additionally, the density of the phosphor particles 402, 410 at or adjacent to the layer interfaces 422, 412, and 424 may also increase rapidly.

[0056] Reference Figure 5, showing a fourth exemplary embodiment of the present invention. In some embodiments, the light conversion system 50 relates to the light conversion systems 20, 30, 40. The light conversion system 50 may include a volume heterogeneous 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 first-type phosphor particles 510 and a distribution of a plurality of second-type phosphor particles 502 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 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, causing the light 504 to be converted into converted light 506 and emitted from the conversion core 500.

[0057] The distribution of the phosphor particles 502, 510 may be intentionally arranged in a series of sub-layers within the transmission medium 501. 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 504. As compared with FIG. 1 and Figure 2B compared to Figure 5 it may be shown that there is an increase in the light conversion level depicted by the converted light 506 emitted from the conversion core 500, and it may also be shown that there is no light depicted as being emitted from the distal end 526 of the conversion core 500. This may 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 gradient increase in the density of the phosphor particles 502, 510.

[0058] The distribution of the phosphor particles 502, 510 volumetrically suspended in the conversion core 500 may be heterogeneous. As shown, the percentage of the first-type phosphor particles 510 volumetrically suspended in the left core 514 of the conversion core 500 is relatively small, while the percentage of the second-type phosphor particles 502 volumetrically suspended in the right core 520 of the conversion core 500 is relatively large. There may be a continuous gradient increase in the density of the first-type phosphor particles 510 adjacent to the proximal end 528 to the density of the second-type phosphor particles 502 adjacent to the distal end 526.

[0059] The volume suspension of phosphor particles 502, 510 can form a gradient phosphor core in the conversion core 500. In one embodiment, the volume suspension of phosphor particles 502, 510 can cause more phosphor particles to interact with light 504 and participate 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 can significantly increase the efficiency of the light conversion system 50 while allowing the overall size of the light source for subsequent light output to be relatively small. In one embodiment, the arrangement, density, chemical composition, composition, and / or percentage of phosphor particles 502, 510 suspended in the transmissive medium 501 of the conversion core 500 can cause more phosphor particles 502, 510 to interact with light 504 and participate in light conversion.

[0060] Reference Figure 6 , shows a fifth exemplary embodiment of the present invention. In some embodiments, the light conversion system 60 relates to the light conversion systems 20, 30, 40, 50. The light conversion system 60 can include a heterogeneous conversion core 600 having a proximal end 262, a proximal end 628, a transmissive medium 601, and phosphor particles 602, 610. The conversion core 600 can include a left core 614, a right core 616, a layer interface 612, a distribution of a plurality of first-type phosphor particles 610 distributed in the left core 614, and a distribution of a plurality of second-type phosphor particles 602 distributed in the right core 616. The conversion core 600 can be optically coupled to a light source that emits light 604. The light 604 can enter the transmissive medium 601 of the conversion core 600 from the left core 614. In one embodiment, the light 604 can interact with the phosphor particles 602, 610, thereby causing converted light 606 to be emitted from the conversion core 600.

[0061] The distribution of phosphor particles 602, 610 can be intentionally arranged in a series of sub-layers in the transmissive medium 601. The series of sub-layers can be intentionally arranged in thicker layers or groups of layers configured to continuously broaden the absorption of light 604. As compared with FIG. 1 and Figure 2B compared, Figure 6 it can be shown that the light conversion level depicted by the converted light 606 emitted from the conversion core 600 increases, and it is shown that no light is depicted being 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 gradient increase in the density of phosphor particles 602, 610.

[0062] The distribution of phosphor particles 602, 610 volumetrically suspended in conversion core 600 can be non-uniform. As shown in the figure, the percentage of the first type of phosphor particles 610 volumetrically suspended in the left core 614 of conversion core 600 is relatively small, while the percentage of the second type of phosphor particles 602 volumetrically suspended in the right core 616 of conversion core 600 is relatively large. There can be a discontinuous gradient increase in density from the first type of phosphor particles 610 at proximal end 628 to the second type of phosphor particles 602 adjacent to distal end 626. Additionally, the density of phosphor particles 602, 610 at layer interface 612 may also increase rapidly.

[0063] Reference Figure 7 , showing 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 can include a non-uniform conversion core 700 having a proximal end 732, a distal end 730, a transmissive medium 701, and phosphor particles 702, 710, 728, 726. Conversion core 700 can 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 702, and layer interfaces 722, 712, and 724. Layer interface 722 can be disposed between left core 714 and left middle core 716. Layer interface 712 can be disposed between left middle core 716 and right middle core 718. Layer interface 724 can be disposed between right middle core 718 and right core 720.

[0064] Each of the left core 714, left middle core 716, right middle core 718, and right core 720 of conversion core 700 can be distinguished by a specific density, composition, percentage, and / or chemical composition. Conversion core 700 can be optically coupled to a light source that emits light 704. Light 704 can enter the transmissive medium 701 of conversion core 700 from left core 714. In one embodiment, light 704 can interact with phosphor particles 702, 726, 728, 710, thereby causing the emission of converted light 706. The distribution of phosphor particles 702, 726, 728, 710 can be intentionally arranged in a series of sub-layers in transmissive 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 light 704. As compared with FIG. 1 and Figure 2B in comparison, Figure 7An increase in the light conversion level depicted by the converted light 706 emitted from the conversion core 700 can be shown, and the unconverted light emitted from the distal end 730 of the conversion core 700 is not depicted. This may 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 gradient increase in the density of the phosphor particles 702, 710, 726, 728.

[0065] The distribution of the phosphor particles 702, 710, 726, 728 suspended in the transmission medium 701 of the conversion core 700 can be inhomogeneous. As shown in the figure, the percentage of the first type of phosphor particles 710 suspended in the left core 714 of the conversion core 700 is relatively small, while the percentage of the fourth type of phosphor particles 702 suspended in the right core 720 of the conversion core 700 is relatively large. From the left core 714 with the first type of phosphor particles 710 through the left middle core 716 with the second type of phosphor particles 726, through the right middle core 718 with the third type of phosphor particles 728 to the right core 720 with the fourth type of phosphor particles 702, there may be a discontinuous gradient increase in the density of the phosphor particles. At the layer interfaces 712, 722, and 724, the phosphor particles 702, 710, 726, 728 may also increase sharply.

[0066] Reference Figure 8 , a diagram showing the relationship between the density of the phosphor particles distributed throughout the transmission medium and the length of the volumetric phosphor conversion core is shown. The density can increase in a single discontinuous non-linear gradient. This discontinuous increase can be shown by a stepped diagram.

[0067] Reference Figure 9 , a diagram showing the relationship between the density of the phosphor particles distributed throughout the transmission medium and the length of the volumetric phosphor conversion core, where the density can increase in a single continuous non-linear gradient.

[0068] Reference Figure 10 , a diagram showing the relationship between the density of the phosphor particles distributed throughout the transmission medium and the length of the volumetric phosphor conversion core, where the density can increase in multiple discontinuous non-linear gradients. This discontinuous increase can be shown by a stepped diagram.

[0069] Reference Figure 11 , a diagram showing the relationship between the density of the phosphor particles distributed throughout the transmission medium and the length of the volumetric phosphor conversion core, where the density can increase in multiple continuous non-linear gradients.

[0070] Reference Figure 12, shows a graph showing the relationship between the density of phosphor particles distributed throughout a transmissive medium and the length of a bulk phosphor conversion core, where the density can increase in a single continuous linear gradient.

[0071] refer to Figure 13 , shows a schematic diagram of a light converter system showing an exemplary arrangement of layers and sublayers. For example, layer 1 1300-1 can be composed of individual sublayers, layer 2 1300-2 can be composed of individual sublayers, and layer 3 1300-3 can be composed of individual sublayers. The individual sublayers of each layer 1300-1, 1300-2, 1300-3 can have similar or identical phosphor particle densities and compositions. At a minimum, the thickness of a sublayer can be the diameter of a single phosphor particle. However, the thickness of a sublayer can be the diameter of two phosphor particles, three phosphor particles, four phosphor particles, or more than four phosphor particles. The thickness of the sublayer depends on the light conversion and modulation properties required for each use case. Each layer can be composed of tens, hundreds, thousands, or millions of sublayers.

[0072] refer to Figures 14A to 14C , shows a schematic diagram of a light converter system showing an exemplary radial arrangement of phosphor particle density within a volume phosphor conversion core. Figures 14A to 14C In , a higher shadow density can indicate a higher phosphor particle density. For example, in Figure 14A In one embodiment shown, the phosphor particle distribution can be arranged in such a way that each layer can have a gradient phosphor distribution 1401, where the density of phosphor particles increases radially outward from the center. Figure 14B In another embodiment shown, the various layers may have a gradient phosphor distribution 1402 where the density of phosphor particles decreases radially outward from the center, or may be in any other arrangement where the variation in phosphor particle density may be continuous or discontinuous. Figure 14C In yet another embodiment shown, these aforementioned radial layers can be arranged in a volumetric shape, such as a cylinder 1403, wherein each radial layer can be different from the layers before and after it. The volumetric shapes described herein are not limited to cylinders, and radial layers can be used for volumetric shapes such as, but not limited to, prisms, cones, cubes, or any other solid geometric shapes. The solid geometric shape constructed using these radial layers can have different densities throughout the radial 1404 and / or axial 1405 directions.

[0073] Those skilled in the art will understand that changes can be made to the exemplary embodiments shown and described above without departing from their broad inventive concept. Accordingly, it is to be understood that the present invention is not limited to the exemplary embodiments shown and described, but is intended to cover modifications within the spirit and scope of the 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 stated herein, the terms "a", "an", and "the" are not limited to one element, but should be construed to mean "at least one".

[0074] It should be understood that at least some of the drawings and descriptions of the present invention have been simplified to focus on elements relevant to a clear understanding of the present invention, while omitting other elements that those of ordinary skill in the art will understand may also be part of the present invention for the purpose of clarity. However, since such elements are well known in the art and since they do not necessarily facilitate a better understanding of the present invention, a description of such elements is not provided herein.

[0075] In addition, insofar as the methods of the present invention do not depend on the specific order of steps set forth herein, the specific order of steps should not be construed as a limitation on the claims. Any claims directed to the methods of the present invention should not be limited to performing their steps in the order written, and those skilled in the art can readily understand that the steps can be varied and still remain within the spirit and scope of the present invention.

Claims

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

2. The light source converter according to claim 1, wherein the plurality of phosphor particles include two or more phosphor particle percentages, compositions, sizes, and / or chemical compositions.

3. The light source converter according to claim 2, wherein the two or more phosphor particle percentages across the length of the transmissive medium are from about 0% to about 100%.

4. The light source converter according to claim 2, wherein the two or more phosphor particle percentages across the length of the transmissive medium are from about 0.1% to about 25%.

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

6. The light source converter according to claim 5, wherein one or more of the percentages, chemical compositions, sizes, and compositions of the two or more phosphor particles are configured to continuously broaden the absorption band of light from the light source.

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

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

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

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

Images