Assembly with visible light radiator

Abstract

An assembly converting input light to output light comprising a visible light radiator adapted to receive and convert the input light in the form of infrared light to an output light formed as visible laser light, and a photovoltaic cell operatively connected to the visible light radiator and adapted to receive the visible laser light from the visible light radiator and generate direct current electricity.

Description

ASSEMBLY WITH VISIBLE LIGHT RADIATORThis patent application claims priority benefit of US Provisional Patent Application 63 / 727,843, filed on December 4, 2024.FIELD OF THE INVENTION

[0001] This invention relates to assemblies using a visible light radiator converting infrared wavelengths of light to visible wavelengths of light for power generation and efficient transfer.BACKGROUND OF THE INVENTION

[0002] Large amounts of infrared radiation reach the earth but is not used. It would be desirable to convert such energy to more useful wavelengths for use with photovoltaic cells, either directly or through relays.SUMMARY OF THE INVENTION

[0003] In accordance with a first aspect, an assembly converting input light to output light comprises a visible light radiator adapted to receive and convert the input light in the form of infrared light to an output light formed as visible laser light, and a photovoltaic cell operatively connected to the visible light radiator and adapted to11813-00011receive the visible laser light from the visible light radiator and generate direct current electricity.

[0004] From the foregoing disclosure and the following more detailed description of various embodiments, it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology assemblies using visible light radiators. Particularly significant in this regard is the potential the invention affords for providing a device which can take advantage of a source of infrared light. Additional elements and advantages of various embodiments will be better understood in view of the detailed description provided below.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Fig. 1 is a schematic of a visible light radiator (“VLR”) suitable for converting light from one frequency to another, such as from infrared to visible light.

[0006] Fig. 2 is a schematic of a waste heat source of infrared light converted to visible light, available to be beamed to space and delivered to a remote or satellite bound photovoltaic cell.

[0007] Fig. 3 shows a graph of frequencies vs. rate of penetration of the earth’s atmosphere.21813-00011

[0008] Fig. 4 shows a schematic of an embodiment where the visible light radiator is used with a series of satellites, with transmission of light produced by the visible light radiator transferred from the earth and between the series of satellites, and back down to earth at a different location.

[0009] Fig. 5 shows an example of a visible light radiator relay used in the embodiment of Fig. 4.

[0010] Fig. 6 shows examples of satellite locations with respect to LaGrange points around the earth which can receive and / or transmit light generated by VLRs.

[0011] Fig. 7 shows an embodiment of the VLR where a beam of visible light projected to a plane of a photovoltaic cell, using internal reflection to distribute the visible light across the photovoltaic cell.

[0012] Fig. 8 shows a schematic where VLRs are used with photovoltaic cells buried but operatively connected to sources of visible light.

[0013] Fig. 9 shows a schematic where VLRs used multiple incoming sources for upconversion to output visible laser light.

[0014] It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of31813-00011the basic principles of the invention. The specific design features of the devices disclosed here, including, for example, the specific dimensions of the visible light radiator, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to help provide a clear understanding. In particular, thin features may be thickened, for example, for clarity of illustration. All references to direction and position, unless otherwise indicated, refer to the orientation illustrated in the drawings.DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0015] It will be apparent to those skilled in the art, that is, to those who have knowledge or experience in this area of technology, that many uses and design variations are possible for the devices using a visible light radiator disclosed here. The following detailed discussion of various alternate elements and embodiments will illustrate the general principles of the invention with reference to a device useful for the generation of electricity, either directly or indirectly. Other embodiments suitable for other applications will be apparent to those skilled in the art given the benefit of this disclosure.

[0016] Turning now to the drawings, Fig. 1 shows a visible light radiator 10 in accordance with one embodiment, using upconversion. Upconversion is a nonlinear optical process that involves the mixing of two or more low-energy photons to produce a single high-energy photon. Sources of incoming light 12 can be laser light, sunlight or41813-00011sunlight amplified with solar collectors, or waste heat such as wase heat from industrial processes. The incoming light 12 can be infrared with a frequency around 1064 nm and the outgoing light 29 may be shifted to visible light output frequency such as green light at around 532 nm, for example. Green light is a suitable output light 29 in that it can be readily used as a source light for a photovoltaic cell. Further, green light around the disclosed wavelengths is relatively transmissible through the atmosphere, such as to or from a ground-based station up to one or more satellites, and also can be transmitted via fiber optic cables. Fig. 1 shows incoming infrared light converted to visible light using a laser pump 14. The laser pump converts incoming light to laser light and can comprise, for example, an 808 nm laser pump diode 16 positioned in front of a laser pump focusing lens 18.

[0017] The laser pump 14 will output laser light at a frequency that is not well suited for use in transmission. Therefore, from the lens 18 laser light is passed to a composite crystal structure comprising a first crystal 20 and a second crystal 22. This composite crystal structure is used with laser light to generate a stable green light through a process called second harmonic generation. The first crystal 20 can comprise, for example, a Neodymium-doped yttrium orthovanadate (Nd:YVO4) crystal which acts as a laser gain medium, producing an infrared laser beam of intermediate frequency. The lasing action of Nd:YVO4 is due to its content of neodymium ions, which may be excited by visible or infrared light, and undergo an electronic transition resulting in emission of coherent infrared light at a lower frequency, usually at 1064 nm (other transitions in Nd are available, and can be selected for by external optics). From first crystal 20, the51813-00011laser light is then immediately directed into the second crystal 22, which can comprise a nonlinear optical material. The nonlinear optical material doubles the frequency of the infrared light to create the visible green laser beam. The output laser light is quasiphase-matched, as the nonlinear optics disclosed herein allows a positive net flow of energy from the pump or incoming frequency to the output laser light by creating a periodic structure in the nonlinear medium / crystal.

[0018] Suitable materials for use in frequency doubling of solid-state lasers used for visible light radiators disclosed here can comprise a non-linear optical crystal such as potassium titanyl phosphate (KTP) crystals, to produce green laser light. A hexagonal lattice of sodium yttrium fluoride (NaYF4) doped with erbium and ytterbium may also be used. Another option is periodic poled stoichiometric lithium tantalate (PPSLT) crystals to enhance phase matching and improve energy conversion efficiency. Laser light (in phase single wavelength), black body silicon wafer emitters and sunlight (unphased full spectrum) can be used as an input light source 12. Sunlight may be amplified with solar collectors prior to delivery to the visible light radiators. A housing 30 may hold the laser pump and the composite crystal structure 20,22, as further, the green laser light 29 may be passed through an expanding lens 24 and a collimating lens 26, and through an IR filter 28, as shown. Additional pre-filtering of the output laser light 29 may be done prior to introduction to a photovoltaic cell for direct current electricity generation.

[0019] Fig. 2 shows a schematic where a waste heat source 31 is used in combination with a black body emitter 32 to produce infrared radiation IR which is converted by a61813-00011visible light radiator 10 (and bumped up to visible laser light at second crystal 22) to the output light. From there the output light is directly directed to one or more photovoltaic cells 40 for generation of direct current electricity. Advantageously, the photovoltaic device can be remote from the sun, can be positioned on a satellite or on the ground or buried, or mounted on a tower to ensure increased amounts of radiation are received as input light. The visible laser light can be directed directly at the photovoltaic device, or it can be beamed and delivered remotely to the photovoltaic devices. Several optical elements may be positioned between the composite crystal structure of the VLR and the photovoltaic device, especially where relatively lengthy transmission is envisioned. For example, along a travel path from the visible light radiator to the photovoltaic device, a ball lens can be used near the photovoltaic cell. A ball lens is a lens where the surfaces' radii of curvature are equal to the radius of the lens itself. A ball lens refracts light at the interface between its surface and its surroundings. Light from a collimated source (i.e., the input laser light) is bent into a converging cone. The rays travel in straight lines within the lens, and then are bent again when they exit, converging to a focal point which is typically just outside the ball. From the ball lens, a diffuser may be used, followed by a collimator may be positioned along the travel path to standardize an incident angle of the of the output laser beam prior to delivery to the photovoltaic cell.

[0020] Fig. 3 shows representative data about the use of green visible light as the output laser light. Green light at a frequency of around 532 nm has the advantages of reasonable photovoltaic efficiency, atmospheric penetration, and can be transmitted along fiber optic cables, whereas other frequencies, such as those in the 700-1064nm71813-00011range, have poor atmospheric penetration. Thus, use of an output light at or near green light at a frequency of 532 nm is useful for transmission through the earth’s atmosphere.

[0021] Fig. 4 shows a representative example of an assembly comprising a series of satellites 50 arranged around at least a portion of the earth. In these embodiments the photovoltaic cell is remote from the visible light radiator. Infrared wavelengths may be converted to visible wavelengths, either at first location such as a ground-based station / tower or at one of the satellites, transmitted to another satellite and then relayed down to earth at a second location. Typically, the first location can be in a sunny location and the second location would be in the dark (i.e. , nighttime or overcast conditions). Thus, photovoltaic cells used with the visible light radiators disclosed herein can operate at night or in dark conditions where otherwise electricity generation would be greatly reduced minimal. When a series of satellites are used, different satellites can beam down the output laser light at different times, as needed on the ground (or as needed at other satellites).

[0022] Fig. 5 is an example of a visible light radiator relay in accordance with one embodiment. In this embodiment the visible light radiator 10 is mounted on a satellite 50. Incoming light may be focused by a reflector 51 , converted to an output visible laser light, collimated at collimator 26 and sent to another satellite or to a ground location as a private wireless network (PWM) collimated beam. The ground location can be in darkness as noted above, and allows for electricity generation with photovoltaic cells even when minimal or no light is available.81813-00011

[0023] Fig. 6 is an example of an assembly comprising a series of satellites 50 positioned at Lagrange points (L1 , L2, L3, L4, L5,) and capable of receiving and / or transmitting beams generated by visible light radiators to act as a power source supplying energy to a particular spacecraft 60. This embodiment allows for power supply to remote spacecraft.

[0024] Fig. 7 shows another embodiment where the output laser light 29 may be delivered to a photovoltaic cell 40 through a fiber optic cable 42 at an incident angle and allow for internal reflections to distribute the output light evenly across the photovoltaic cells. Input light can prefiltered to reduce harmful rays, and may be quasi-phase matched, and distributed to the photovoltaic cell(s) via total internal reflection in a fiber optic cable, for example, broken by frosting the surface. The edge-lit solar collection assembly disclosed here would illuminate a frosted surface 72 of a clear acrylic panel 70 positioned between the fiber optic cable 42 and the photovoltaic cells 40, advantageously distributing the output laser light across surfaces of the photovoltaic cell to enhance energy absorption. The acrylic material of the panel 70 can have a refractive index of about 1 .49, for example. The panel 70 is show having a length generally equal to a photovoltaic cell length, and the photovoltaic cell may be provided with a pair of light receiving surfaces facing one another, as shown. The panel 70 and photovoltaic cell 40 arrangement allows for underground energy collection or other hidden installations where PV cells are shielded from environmental damage while still capturing energy.91813-00011

[0025] Fig. 8 shows a simplified schematic of an embodiment where the photovoltaic cell 240 is below ground, in a building or otherwise away from element which would normally damage the photovoltaic cell, or at least reduce electricity generation efficiency. Output laser light can come from any one or more of several sources, such as from a satellite 50, another fiber optic source 96 via fiber optic cables 95, or by reflection 97 (such as from an IR source from waste heat, for example), and beamed to the underground photovoltaic array / monolith.

[0026] Fig. 9 shows an example of a visible light radiator converting both visible light and IR light to produce visible output laser light. The input light can be a mixture of several input sources, such as infrared and visible 112 along with just visible light and converted to infrared using a hot mirror 80, for example. The hot mirror is a specialized dielectric mirror, a dichroic filter, used to reflect infrared light while allowing visible light to pass. Light travels along a travel path from the hot mirror to the rest of the visible light radiator and then eventually to the photovoltaic cell. Generally optical and infrared focusing technologies can comprise plastic Fresnel lenses, mirrors, and chalcogenide glass to focus and control long-wave IR light. These elements of the invention would help in creating efficient systems for redirecting and focusing infrared radiation either for local energy generation or transmission to other systems. Output visible laser light (which has passed through a compact lens 124 such as a fresnel lens and collimator 26) can then be directly or indirectly operatively connected to an output tube 90. The output tube may be provided with a frosted or etched layer 92. A PPSLT layer 122 in101813-00011semicylindrical form (???) is shown, along with a semicylindrical photovoltaic cell 140.The photovoltaic cell converts the output visible laser light to electricity which can be transferred to a battery.

[0027] From the foregoing disclosure and detailed description of certain embodiments, it will be apparent that various modifications, additions, and other alternative embodiments are possible without departing from the true scope of the invention. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to use the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.111813-00011

Claims

ASSEMBLY WITH VISIBLE LIGHT RADIATORCLAIMSWhat is claimed is:1 . An assembly converting input light to output light comprising, in combination: a visible light radiator adapted to receive and convert the input light in the form of infrared light to an output light formed as visible laser light; and a photovoltaic cell operatively connected to the visible light radiator and adapted to receive the visible laser light from the visible light radiator and generate direct current electricity.

2. The assembly of claim 1 wherein the photovoltaic cell is positioned away from direct sunlight.

3. The assembly of claim 1 wherein the visible light radiator is positioned on a satellite, and output light is beamed to the photovoltaic cell located on one of the ground, the satellite and another satellite.

4. The assembly of claim 3 further comprising a reflector mounted on the satellite, wherein the reflector reflects input light to the visible light radiator.

5. The assembly of claim 1 wherein the visible light radiator comprises a laser pump and a composite crystal structure, wherein input light is converted to laser light by the11813-00011ASSEMBLY WITH VISIBLE LIGHT RADIATOR laser pump, and the laser light is converted to visible laser light by the composite crystal structure.

6. The assembly of claim 5 wherein the laser pump comprises a laser pump diode and a focusing lens, wherein the input light passes through the laser pump diode and is converted to laser light before traveling the focusing lens.

7. The assembly of claim 6 wherein the composite crystal structure comprises a first crystal and a second crystal, wherein the first crystal converts the laser light to an intermediate frequency, and the second crystal comprises a nonlinear optical material which converts the intermediate frequency to a visible laser light frequency.

8. The assembly of claim 7 wherein: the first crystal is a neodymium-doped yttrium orthovanadate (Nd:YV04) crystal; the second crystal is one of a potassium titanyl phosphate (KTP) crystal, a hexagonal lattice of sodium yttrium fluoride (NaYF4) doped with erbium and ytterbium, and a periodic poled stoichiometric lithium tantalate (PPSLT); and the visible laser light is green laser light.

9. The assembly of claim 1 wherein the output laser light travels along a travel path from the visible light radiator to the photovoltaic cell through a ball lens.21813-00011ASSEMBLY WITH VISIBLE LIGHT RADIATOR10. The assembly of claim 1 wherein the output laser light is delivered to the photovoltaic cell via a fiber optic cable.

11. The assembly of claim 10 further comprising a panel positioned between the fiber optic cable and the photovoltaic cell, wherein the panel has a frosted surface, and the output laser light is distributed across the photovoltaic cell12. The assembly of claim 1 further comprising a hot mirror positioned in front of the visible light radiator along a travel path of input light.

13. The assembly of claim 1 further comprising a black body emitter 32 adapted to heat from a heat source to produce infrared radiation IR which is converted by the visible light radiator to the output light.31813-00011

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