Optical wireless power supply system

Abstract

To provide a laser-based transmission system that radiates optical power in a beam to a mobile electronic device in a home environment.SOLUTION: A transmitter 21 that incorporates a safety system 31 and transmits optical power to a receiver 22 includes an optical resonator having multiple mirrors 9, 10 and a gain medium 11, a laser driver 12 that supplies power to the gain medium to control its small-signal gain, a beam steering device 14, and a controller 13 that controls at least the beam steering device and the laser driver. The controller outputs instructions for changing at least some of the small-signal gain of the gain medium, the radiant intensity of an optical beam 15, power supplied by the driver, and the scan speed or scan direction and position of the beam steering device or instructions for registering a scan attitude that determines the arrangement of the optical / power converter, thereby responds to safety risks arising in the system, ensures high overall radiant intensity efficiency, and can warn that the target receiver is not receiving the transmitted power.SELECTED DRAWING: Figure 19

Description

Technical Field

[0001] The present invention relates to the field of wireless power beam radiation, and more particularly, to the use of a laser-based transmission system for beaming optical power to a mobile electronic device in a home environment, where applicable. It relates to the use of a laser-based transmission system for beaming optical power to a mobile electronic device in a home environment, where applicable. It relates to the use of a laser-based transmission system for beaming optical power to a mobile electronic device in a home environment, where applicable.

Background Art

[0002] There has been a long-standing and pressing need to transmit power to remote locations without the need for a physical wired connection. This need has become important over the past few decades as portable electronic devices that operate on batteries requiring periodic recharging have become common. Such mobile applications include mobile phones, laptop computers, vehicles, toys, wearable devices, and hearing aids. Currently, the capacity of the latest batteries and the typical use of batteries in smartphones require battery recharging at least once a day, making the need for remote wireless battery recharging important. Such mobile applications include mobile phones, laptop computers, vehicles, toys, wearable devices, and hearing aids. Currently, the capacity of the latest batteries and the typical use of batteries in smartphones require battery recharging at least once a day, making the need for remote wireless battery recharging important. Such mobile applications include mobile phones, laptop computers, vehicles, toys, wearable devices, and hearing aids. Currently, the capacity of the latest batteries and the typical use of batteries in smartphones require battery recharging at least once a day, making the need for remote wireless battery recharging important. Such mobile applications include mobile phones, laptop computers, vehicles, toys, wearable devices, and hearing aids. Currently, the capacity of the latest batteries and the typical use of batteries in smartphones require battery recharging at least once a day, making the need for remote wireless battery recharging important. Such mobile applications include mobile phones, laptop computers, vehicles, toys, wearable devices, and hearing aids. Currently, the capacity of the latest batteries and the typical use of batteries in smartphones require battery recharging at least once a day, making the need for remote wireless battery recharging important. Such mobile applications include mobile phones, laptop computers, vehicles, toys, wearable devices, and hearing aids. Currently, the capacity of the latest batteries and the typical use of batteries in smartphones require battery recharging at least once a day, making the need for remote wireless battery recharging important.

[0003] Battery technology has a long history and is still under development. In 1748, Benjamin Franklin described the first battery (battery) made from a Leyden jar, i.e., the first power source. This resembled a battery of cannons (hence the name battery). In the late 1800s, Volta invented the copper-zinc battery. This was the first truly portable battery. The first rechargeable battery, the lead-acid battery, was invented by Gaston Planté in 1859. Since then, the increase in the energy density of rechargeable batteries has been achieved through various chemistries from the original lead-acid chemistry to the current lithium-based and zinc-air chemistries. Battery technology has a long history and is still under development. In 1748, Benjamin Franklin described the first battery (battery) made from a Leyden jar, i.e., the first power source. This resembled a battery of cannons (hence the name battery). In the late 1800s, Volta invented the copper-zinc battery. This was the first truly portable battery. The first rechargeable battery, the lead-acid battery, was invented by Gaston Planté in 1859. Since then, the increase in the energy density of rechargeable batteries has been achieved through various chemistries from the original lead-acid chemistry to the current lithium-based and zinc-air chemistries. Battery technology has a long history and is still under development. In 1748, Benjamin Franklin described the first battery (battery) made from a Leyden jar, i.e., the first power source. This resembled a battery of cannons (hence the name battery). In the late 1800s, Volta invented the copper-zinc battery. This was the first truly portable battery. The first rechargeable battery, the lead-acid battery, was invented by Gaston Planté in 1859. Since then, the increase in the energy density of rechargeable batteries has been achieved through various chemistries from the original lead-acid chemistry to the current lithium-based and zinc-air chemistries. Battery technology has a long history and is still under development. In 1748, Benjamin Franklin described the first battery (battery) made from a Leyden jar, i.e., the first power source. This resembled a battery of cannons (hence the name battery). In the late 1800s, Volta invented the copper-zinc battery. This was the first truly portable battery. The first rechargeable battery, the lead-acid battery, was invented by Gaston Planté in 1859. Since then, the increase in the energy density of rechargeable batteries has been achieved through various chemistries from the original lead-acid chemistry to the current lithium-based and zinc-air chemistries. Battery technology has a long history and is still under development. In 1748, Benjamin Franklin described the first battery (battery) made from a Leyden jar, i.e., the first power source. This resembled a battery of cannons (hence the name battery). In the late 1800s, Volta invented the copper-zinc battery. This was the first truly portable battery. The first rechargeable battery, the lead-acid battery, was invented by Gaston Planté in 1859. Since then, the increase in the energy density of rechargeable batteries has been achieved through various chemistries from the original lead-acid chemistry to the current lithium-based and zinc-air chemistries. Battery technology has a long history and is still under development. In 1748, Benjamin Franklin described the first battery (battery) made from a Leyden jar, i.e., the first power source. This resembled a battery of cannons (hence the name battery). In the late 1800s, Volta invented the copper-zinc battery. This was the first truly portable battery. The first rechargeable battery, the lead-acid battery, was invented by Gaston Planté in 1859. Since then, the increase in the energy density of rechargeable batteries has been achieved through various chemistries from the original lead-acid chemistry to the current lithium-based and zinc-air chemistries. Battery technology has a long history and is still under development. In 1748, Benjamin Franklin described the first battery (battery) made from a Leyden jar, i.e., the first power source. This resembled a battery of cannons (hence the name battery). In the late 1800s, Volta invented the copper-zinc battery. This was the first truly portable battery. The first rechargeable battery, the lead-acid battery, was invented by Gaston Planté in 1859. Since then, the increase in the energy density of rechargeable batteries has been achieved through various chemistries from the original lead-acid chemistry to the current lithium-based and zinc-air chemistries. Exhibit the energy density of the rechargeable battery in both weight and volume parameters As can be seen in Figure 1, it is less than 8 times. At the same time, the power consumed by portable electronic / electrical devices has reached the point where several full battery charges need to be replenished daily.

[0004] Nearly a century after the invention of the battery, during the period from 1870 to 1910, Tesla attempted to transmit power over long distances using electromagnetic waves. Since then, many attempts have been made to safely transmit power to remote locations that can be characterized by the transmitting device being significantly farther than the receiving device. This ranges from NASA, which directed the Stationary High Altitude Relay Platform (SHARP) project in the 1980s, to Marin Soljacic, who conducted experiments with a system similar to Tesla's in 2007. Even so, so far, there are only three commercially available technologies that allow wireless power transfer to mobile devices. That is, as follows.

[0005] Magnetic induction... This is typically limited to a range of only a few millimeters. Photovoltaic cells... These cannot generate more than 0.1 watts for the size related to a mobile phone when irradiated by either sunlight or the available level of artificial light in a normal (safe) illuminated room. Energy harvesting technology... This converts RF waves into usable energy, but in the current practical situation, it cannot operate beyond 0.01W. The RF signal ​​​​​​​​​​​​​Transmission is limited because of health and Federal Communications Commission (FCC) regulations. On the other hand, typical batteries of portable electronic devices have a capacity of 1 to 100 watt-hours and typically require daily charging. Therefore, there is a need for fairly high power transfer over a fairly long range.

[0006] Accordingly, there remains an unaddressed need to safely transfer power over a large field of view and a range greater than a few meters, up to a portable electronic device typically equipped with a rechargeable battery.

[0007] Attempts have been made to transfer power in a residential environment using collimated or essentially collimated electromagnetic waves, particularly laser beams. However, the commercial viability of such products for the mass market is currently limited. Before launching such a commercial system, several problems need to be solved. That is, a safe system should be developed. A cost-effective system should be developed. A system should be developed that can withstand the hazards of a normal home environment, including contamination such as dust and fingerprints or spills of liquids, vibrations, beam blockage, placement by non-experts, and occasional drops to the floor. The currently permitted transmitted laser power levels are insufficient to provide a useful amount of power without a complex safety system. For example, in the United States, the Federal Regulations Code, Title 21, Volume 8 (21 CFR Section 8), Chapter I, Subchapter J Part 1040 addresses the performance standards for light-emitting products, including laser products. For wavelengths outside the visible range,

[0008] revised in April 2014, ​​​​​​​There are Class I, Class III-b, and Class IV lasers (Classes II, II a, and IIIa are lasers in the range of 400 nm to 710 nm, such as visible lasers). For lasers outside the visible range, Class 1 is considered safe for general public use, while Classes III-b and IV are considered dangerous.

[0009] Refer to Figure 2 here. This is a graph showing the MPE (Maximum Permissible Exposure Value) of Class I lasers with a pupil diameter of 7 mm according to 21 CFR Section 8 for exposures from 0.1 to 60 seconds. The following can be seen from the graph: (i) The maximum permissible exposure level generally (but not necessarily always) increases with wavelength, and (ii) To meet the requirements specified in 21 CFR Section 8, even if a person enters the beam and the laser is turned off 0.1 second later, light not exceeding 1.25 W can be transmitted at wavelengths longer than 2.5 μm. As the wavelength shortens, the limiting digit number also decreases. That is, without a certain safety system, a laser power of only a few milli watts can be transmitted. This represents a power supply that is significantly smaller than the power required to charge most portable electronic devices, even if it is fully converted back to electricity. For example, a cellular phone requires 1 to 12 W to charge depending on the model.

[0010]

[0011] A safety system is required to transmit power higher than the Class 1 laser MPE. To date, nothing that transmits significant levels of power in a residential environment where untrained people can approach has been commercialized, to the applicant's knowledge.

[0011] ​​It is difficult to build a transmission system with a robust safety system. The required detection level is very small compared to the power that needs to be transmitted, and the environment in which the system operates is not controlled, and many unpredictable

[0012] It is well known in the industry that fingerprints and dust scatter laser light, and that transparent surfaces reflect or scatter such light. When high power is transferred, a Class IV (or IIIb) laser is required to meet the requirements of a reliable safety system. Even scattered radiation from the main beam is dangerous for Class IV lasers. According to 21 CFR Section 8, Chapter I, Subchapter J, Part 1040, revised in April 2014, laser radiation in the range of 400 nm to 1400 nm with a beam output exceeding 0.5 W is usually considered a Class IV laser for exposures exceeding 0.5 seconds, and even scattered radiation from such a laser can be dangerous. Such lasers must have a key lock and a warning label similar to that shown in Figure 3. Here, the warning is also related to "scattered radiation", and users of such lasers usually need to wear safety googles and are typically trained experts. All of these aspects are very far from the acceptable conditions

[0013] for the use of a laser power transmission system available at home to charge portable electronic devices. Typically, the prior art uses an anti-reflective (Anti-Reflective) film on the surface that prevents such reflections, and The solutions using AR films are prone to failure due to dust or spilled liquid deposited on their surface, or , for example, wear and tear and breakage due to improper cleaning. In addition , beam-blocking solutions typically severely limit the field of view of the system and thus are bulky compared to the dimensions of modern portable electronic devices.

[0014] Therefore, the prior art lacks a reliable "small footprint" mechanism to prevent the power beam from scattering and reflecting in undesirable directions. Such scattering and reflection can be caused by a transparent surface carelessly placed between the transmitter and the receiver, so the optical characteristics of the transparent surface are affected by a vast number of different transparent materials, or by the spillage of liquids and fingerprints that can deposit on the external surface of the system, typically on the front face of the receiver.

[0015] A third problem with the solutions proposed in the prior art is that such safety systems generally require a mechanism to ensure good alignment between the power beam system and the safety system . Thereby, both systems are aimed at the same axis until the power beam is sufficiently dissipated or attenuated (or a combination of these factors with any other factors) so that neither exceeds the safety limit any longer. This is extremely difficult to achieve for collimated Class IV or IIIb laser beams, which typically do not diverge much over distance and thus can exceed the safety limit even at very long distances.

[0016] One operating principle of the prior art used to construct such safety systems is the beam path ​​​​​​​​​It is to optically detect a transparent surface that can be positioned on a road. However, the optical path The transparent surfaces that can enter the path are made of a vast number of different transparent materials, and unless they are anti-reflection AR coated or the material does not absorb the beam, they are arranged at an angle close to the Brewster angle so as to be almost invisible to the optical system. However, the light absorption levels of each substance are different and can even be ignored, and constructing an optical system that depends on light absorption is highly substance-specific, and the number of available substances is extremely large so such a system tends to be complex, large-scale and expensive, and is not reliable unless properly designed , especially considering that it is intended to be an important safety system. There are also problems with relying on reflection to provide a detectable attenuation of the beam . When the surface is coated with an anti-reflection film or arranged at a near Brewster angle to the beam, reflection can be minimized for such a specific position of the surface because of this. There is.

[0017] Another limitation of prior art systems is the use of a laser combined with a large 2 optical system with good beam quality (low m value) to obtain high efficiency (for example, Patent Document 1 and Patent Document 2 use a wide aperture for the laser beam), while Patent Document 3 uses a wavelength of 0.8 μm to allow a small optical system to reduce the cost and size of the optical system.

[0018] Therefore, there is a need for a laser power transmission system with an integrated safety function that overcomes at least some of the disadvantages of prior art systems and methods. There is.

[0019] The disclosure of each of the publications referred to in this section of the specification and other sections is hereby incorporated by reference in its entirety.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0020]

Patent Document 1

Patent Document 2

Patent Document 3

SUMMARY OF THE INVENTION

[0021] One of the main challenges in wireless power transmission is to construct a transmitter and a receiver that are safe, low-cost, small, yet powerful (e.g., capable of transmitting a significant level of power). To enable a powerful and small transmitter and receiver, it is essential to maintain the radiance of the beam as high as possible, particularly at the output of the transmitter, although across the entire optical path. All components in the optical path cause a certain radiance loss. In this specification, the term radiance efficiency is used several times. Its ordinary meaning in the context of this specification is the ratio of the radiance going out of an optical component to the incident radiance of the beam entering the component. For components that can be configured in various ways, for example, a mirror can be tilted at different angles. Different radiation efficiencies can exist for each configuration.

[0022] Generally, the system as a whole needs to have as high a radiation efficiency as possible, with 60% One should strive to obtain typical values ​​of radiation efficiency exceeding 90% or even 95%.

[0023] The radiation efficiency of the transmitter is generally much more important than that of the receiver. There are two main factors that reduce radiance: the laser system and the transmission. Besides these factors, other small factors also have an effect.

[0024] Lasers with high radiance values ​​are generally large and complex, while lasers with low radiance are generally large and complex. The lasers used are typically small and simple. Current systems offer improved safety features. Laser radiance is limited because they typically use rare wavelengths that allow Small, low-cost, high-radiance lasers at unconventional wavelengths are not as commonly available. These techniques tend to increase the cost of the system rather than improve its functionality.

[0025] Prior art systems such as those disclosed in US Pat. Nos. 5,993,333 and 5,943,633 allow compact transmitters and receivers. To accommodate this, shorter wavelengths (0.8 μm or 0.532 μm) are used. Because the system utilizes longer wavelengths, different methods are needed to reduce the size of the system. must be used.

[0026] The longer wavelengths used by current systems are disclosed in commonly owned U.S. patent application Ser. As explained in 14 / 811,260, virtually all plastic materials By using specifically absorbed wavelengths, transparent plastics in the path of the beam This allows detection of the problem.

[0027] Opaque or partially opaque materials, when placed in the beam, also It can be easily detected by measuring the attenuation of mu. However, some materials are transparent or nearly transparent, and it is significantly difficult to detect even such transparent materials. There are two main groups of solid transparent materials. They are organic materials and inorganic materials. The number of inorganic transparent solid materials available to the general public is quite limited. Most are composed of glass, some commonly used semiconductor materials, crystals, and several natural minerals such as diamond, ruby and calcite. Therefore, a detection system for reflection from inorganic transparent materials can be constructed to cover all similar scenarios. .

[0028] On the other hand, the availability of different organic transparent materials to the general public is enormous. New transparent materials are constantly being added to the list. This is an important issue. It is substantially impossible to optically characterize this group.

[0029] Polymers are an important group of transparent organic substances and are used as a sample group to help explain the aspects in which the present invention is intended to operate. Polymers typically consist of long-chain monomers. The backbone of such polymers typically consists of either carbon or silicon. Figures 4 to 9 show the chemical structures of some commonly used transparent polymers. Figure 4 shows a polymethyl methacrylate (PMMA) chain. Figure 5 shows the structure of polycarbonate. Figure 6 shows a polystyrene structure. Figure 7 shows nylon 6,6. Figure 8 shows a polypropylene chain. Figure 9 shows a polyethylene chain structure.

[0030] It will be observed that the chemical structures of the sample polymers shown are very different, and these of the polymers' absorption spectra depend on many factors, including the density of the material, trace amounts of reagents, and chain length. Nevertheless, all of the above-mentioned transparent polymers have some common chemical bonds, particularly C-C bonds and C-H bonds. This is particularly applicable to polymers that are almost completely organic substances that would be detected by the systems of the present disclosure, or to semi-organic silicon-based polymers such as silicone, polysilane, polygermanium and polystannane or polyphosphazene that would be detected by the systems of the present disclosure.

[0031] Separately, the number of transparent materials available to the general public that are not carbon-based chemistry (most of which consist of various glasses) is quite limited. Most of them have data readily available regarding their transmission spectra.

[0032] If the system is designed such that either the vibrational C-H or perhaps the C-C bond within the polymer is excited by the laser, detection is facilitated by monitoring the power drop caused by such a polymer when positioning one such polymer in the beam. This assumes that there is always absorption of C-H or C-C bonds and that it always results in a wavelength that matches the laser wavelength. Rotational peaks can also be used for this purpose, but rotational peaks are not reliable in polymers, so vibrational C-H (or C-C) absorption is well-suited for this purpose.

[0033] ​​​​​​​​​​Refer to FIG. 10 showing a chart of typical absorption regions of different polymer bonds. In almost all of the polymers shown, C-H stretching vibrations -1 near 2900 - 3200 cm are observed to occur. Therefore, this can be used as a trigger for an absorption mechanism for a security system using the change in transmitted power obtained from the absorption band. However, there are two problems that prevent these absorption bands from being useful for this purpose.

[0034] (i) The C-H vibrational absorption lines are typically very sharp, and their exact frequency varies from polymer to polymer, so there is a possibility that the laser may not excite other polymers even if it excites one polymer. That is, the laser is not absorbed unless it is precisely tuned to the specific C-H vibrational line of the polymer. (ii) Such C-H vibration peaks are generally medium absorption peaks, meaning that due to the material section being a few millimeters thick, the beam attenuation becomes 20 - 50% (i.e., even a trace amount of material in a small container can be detected). Medium (20 - 70% attenuation per cm of material) and strong (attenuation exceeding 70% per cm) absorption peaks are generally detected quite easily, so these absorption peaks cannot be used to build a robust system.

[0035] In a commercial system designed for the consumer environment, fingerprints are a common problem. In normal operation, the system must not simply fail due to the deposition of fingerprints. Instead, if there is a risk of exceeding the safety limit, the system shuts down transmission. ​​​​​​​​​​should be. To do this, the system should detect beam blockage, but , should not stop transmission due to any fingerprints deposited on the receiver. If a moderate or strong absorption peak is used, in case there are fingerprints or any other contamination deposited on the external optical surfaces of the receiver or transmitter, the beam will be significantly absorbed and power transmission will fail . This occurs because fingerprints contain organic compounds that absorb the beam and can also cause system malfunctions with poor control. Organic substances such as fingerprints can typically accumulate on the surface of external optical components. To enable the system to operate in an environment where organic substances like fingerprints can accumulate on the surface of external optical components, it is necessary to construct a system where the laser beam can successfully cross the fingerprint while dangerous transparent objects that can be inserted into the beam are detected by the safety system. On the other hand, if the safety system utilizes a weak absorption band instead of a moderate or strong absorption band, the system should be able to operate even with fingerprints and can perform a shut-off based on an electronic decision without being in a state of poor control.

[0036] 800 cm -1 to 1300 cm -1 Looking at the C-C absorption band that extends up to, this is a broad band such that a narrow-band laser will almost certainly miss the narrow-band absorption peak in this region. This is because the peak is located within the range of 800 cm -1 ~1300 cm -1 while its typical width is very small and can be easily missed by some narrow-band lasers. In addition, as can be seen in Figure 11 below, this band disappears for some polymers. In this case, there is no visible absorption peak at 800 - 1300 cm -1 and there is no C​​​​ There are some polymers that do not have -C bonds and are substituted by aromatic carbon-carbon bonds or C=C bonds and C-O-C bonds.

[0037] Further problems arise from the absorption intensity of the C-C line. Detection of symmetric compounds such as polyethylene can be almost impossible, while in other compounds, even the weak fingerprints on the surface of the receiver can become strong enough to disable the system, so a significant portion of the power is absorbed by the fingerprints and the device cannot be used. To enable the operation of a system where fingerprints can be deposited on the optical surface, weak but not too weak absorption lines found in most organic polymers are required, with little difference between different polymers. A laser tuned to such a peak should be used with a system operating near the peak. As can be seen from Figure 10, such peaks do not exist in the absorption bands shown in commonly used polymers.

[0038] A system for optical wireless power transmission to a power receiving device, (a) An optical resonator adapted to emit an optical beam having an end reflector; (b) A gain medium located inside the optical resonator and having a first bandgap energy, the gain medium being thermally attached to a cooling system and configured to amplify the light passing through itself; (c) A collimator lens that reduces the divergence of the light and has a high radiation efficiency (exceeding 50%); (d) A driver that supplies power to the gain medium to control the small-signal gain of the gain medium; (e) Configured to direct the optical beam in at least one of a plurality of directions, typically with high radiation efficiency; A beam steering device having a radiation efficiency (typically exceeding 50%), and (f) an optical / power converter configured to convert an optical beam into power having a voltage, and having a second bandgap energy and a thickness acting as an absorption layer (typically a semiconductor), and (g) a voltage converter adapted to convert the voltage of the power generated by the optical / power converter into a different voltage, and including an inductor, an energy storage device, and a switch, and (h) at least one surface optically disposed between the gain medium and the optical / power converter and associated with the optical / power converter, and (i) a detector configured to provide a signal indicating that the optical beam has impinged on the optical / power converter, and (j) a safety system for evaluating the potential for a safety violation, and (k) a controller adapted to control at least one of the status of the beam steering device and the driver, and receiving at least a control input signal from the detector, and (l) the at least one surface has a property of reflecting a small portion of the incident light such that (i) in more than one direction, or (ii) the reflected light has a virtual focus positioned so as to be remote from the optical resonator with respect to the surface, or (iii) the reflected light has a real focus positioned at least 1 cm in the direction of the optical resonator with respect to the surface, and (m) the controller is configured to (i) change the small signal gain of the gain medium for the driver, (ii) change the radiance of the optical beam, (iii) change the power supplied by the driver, (iv) change the scan speed of the beam steering device, (v) change the scan position of the beam steering device, (vi) the optical ​​​​​​ by at least one of recording a scan position that defines the position of the power converter configured to respond to a control input signal received from the detector (n) the gain medium is a semiconductor device or solid host doped with Nd ions and has a frequency range from 8,300 cm -1 to 12,500 cm -1 including a filter that attenuates radiation at at least one frequency within the range and having a filter that attenuates radiation at at least one frequency within the range (o) the thickness of the active semiconductor layer of the optical / power converter is large enough to absorb most of the optical beam, but not so large as to significantly reduce the quantum efficiency of the semiconductor layer is selected such that and is selected (p) the second bandgap energy is smaller than the first bandgap energy (q) the first bandgap energy is between 0.8 eV and 1.1 eV (r) the switch has a closed series resistance smaller than R given by the formula

Number

[0039] In any such system, the different voltages can be higher than the voltages generated by the photo / electric converter. Further, the status of the beam steering device can be either or both of the aiming direction and the scan speed of the beam steering device. In any such system, the optical beam can have a radiance of at least 800 kW / m / steradian.

[0040] / steradian. 2 / steradian.

[0041] Other implementations may include any of the above systems where each of the end reflectors of the resonator is one of (i) a dielectric mirror, (ii) a Bragg mirror, (iii) a Fresnel reflector, or (iv) a mirror consisting of alternating layers of dielectric or semiconductor materials having different refractive indices. Additionally, the gain medium can be either a transparent solid host material doped with Nd ions or a semiconductor. In such cases, the system may further include a filter that extracts radiation having a wave number greater than 8300 cm / steradian. / steradian. / steradian. / steradian. -1 greater than / steradian. / steradian. When the gain medium is a semiconductor, a quantum dot gain medium may be advantageous.

[0042] In a further typical implementation of the above system, the cooling system can be at least one of a heat sink, a Peltier diode, and a liquid cooling plate. It may be equipped with a fan. Additionally, the gain medium can be attached to the cooling system using a solder layer having a thermal resistance of less than 200 degrees Kelvin per watt. In any case, the cooling system can be made such that the thermal resistance between the gain medium and the ambient air is less than 200 degrees Kelvin per watt. / steradian. / steradian. / steradian. / steradian. 。

[0043] In an alternative implementation of any of the above systems, the optical / power converter may be a photovoltaic cell. In such a case, the photovoltaic cell may be a III-V device. In any case, the series resistance of the optical / power converter should be less than 1 ohm. The optical / power converter typically has a conductor thereon. The conductor has a thickness of at least 0.02 / μ where μ

[0044] is the decimal attenuation coefficient measured in units of 1 / m. / μ 10 Here, μ 10 is the decimal attenuation coefficient measured in units of 1 / m. The conductor should have a thickness of at least (0.01 * Pρ) / (V

[0045] * χ) meters. Here, P is the transmitted power measured in watts absorbed by the photovoltaic cell, ρ is the specific electrical resistivity of the conductor, V is the voltage emitted at the maximum power point by the photovoltaic cell, and χ is the ratio of the area of the absorption layer covered by the conductor. 2 * χ) meters. Here, P is the transmitted power measured in watts absorbed by the photovoltaic cell, ρ is the specific electrical resistivity of the conductor, V is the voltage emitted at the maximum power point by the photovoltaic cell, and χ is the ratio of the area of the absorption layer covered by the conductor. In a further implementation of the above system, the inductor should have a series resistance measured in ohms that is less than the square of the first bandgap energy measured in joules divided by 2 × 10 times the driver power measured in watts. In other implementations, the energy storage device can be either a capacitor or a rechargeable battery. In a further implementation of the above system, inputs from various sensors and monitors are provided.

[0046] In a further implementation of the above system, the inductor should have a series resistance measured in ohms that is less than the square of the first bandgap energy measured in joules divided by 2 × 10 times the driver power measured in watts. times the driver power measured in watts. -40 In other implementations, the energy storage device can be either a capacitor or a rechargeable battery.

[0047] In other implementations, the energy storage device can be either a capacitor or a rechargeable battery. In other implementations, the energy storage device can be either a capacitor or a rechargeable battery.

[0048] In a further implementation of the above system, inputs from various sensors and monitors are provided. It includes at least one safety system for estimating the probability of safety violations. This is different from prior art systems that provide only actual measurement data without indicating the probability of errors, such as the radar system of Patent Document 1. This system is different in that it gives a signal indicating the probability of a safety violation as opposed to an actually detected safety violation. This allows for several significant advantages. First, the system can respond differently to high-risk and low-risk situations in the face of potentially problematic situations revealed by low signal / noise or signal interruptions, for example, treating a low-risk situation caused by, for example, a dirty aperture, misalignment, or a similar event differently from a high-risk situation such as a high-probability beam intrusion or unreasonable beam power whether high or low. Second, the system can combine probabilities from different safety systems into a unified probability to achieve a very high detection accuracy. For example, when the system is designed to have a failure rate of, say, 10 failures per hour in a changing environment, there is no single safety system that can provide such reliable measurements without failure. However, a combination of safety systems can have a favorable failure probability. When such data is combined with the probability of errors and the statistical correlation of errors from both safety systems is known or estimated or approximated, the data from the two systems can be combined so that the data is provided with a significantly high probability. Such reliable data can be used, inter alia, for signals. Unlike prior art systems that provide only actual measurement data without indicating the probability of errors, such as the radar system of Patent Document 1. This system is different from prior art systems that provide only actual measurement data without indicating the probability of errors, such as the radar system of Patent Document 1. This system is different in that it gives a signal indicating the probability of a safety violation as opposed to an actually detected safety violation. This allows for several significant advantages. First, the system can respond differently to high-risk and low-risk situations in the face of potentially problematic situations revealed by low signal / noise or signal interruptions. For example, it can respond differently to each situation. For example, a low-risk situation caused by, for example, a dirty aperture, misalignment, or a similar event can be treated differently from a high-risk situation such as a high-probability beam intrusion or unreasonable beam power whether high or low. For example, a low-risk situation caused by, for example, a dirty aperture, misalignment, or a similar event can be treated differently from a high-risk situation such as a high-probability beam intrusion or unreasonable beam power whether high or low. Second, the system can combine probabilities from different safety systems into a unified probability to achieve a very high detection accuracy. For example, when the system is designed to have a failure rate of, say, 10 failures per hour in a changing environment, there is no single safety system that can provide such reliable measurements without failure. However, a combination of safety systems can have a favorable failure probability. -9 Failure rate of failures When such data is combined with the probability of errors and the statistical correlation of errors from both safety systems is known or estimated or approximated, the data from the two systems can be combined so that the data is provided with a significantly high probability. However, a combination of safety systems can have a favorable failure probability. When such data is combined with the probability of errors and the statistical correlation of errors from both safety systems is known or estimated or approximated, the data from the two systems can be combined so that the data is provided with a significantly high probability. When such data is combined with the probability of errors and the statistical correlation of errors from both safety systems is known or estimated or approximated, the data from the two systems can be combined so that the data is provided with a significantly high probability. When such data is combined with the probability of errors and the statistical correlation of errors from both safety systems is known or estimated or approximated, the data from the two systems can be combined so that the data is provided with a significantly high probability. When such data is combined with the probability of errors and the statistical correlation of errors from both safety systems is known or estimated or approximated, the data from the two systems can be combined so that the data is provided with a significantly high probability. from noise, from the temperature of the component, based on measurements on the same or similar devices or from preload data, or can be estimated from user input information uploaded by the manufacturer or seller or given by the user.

[0049] According to a further implementation of the above system, the output beam of the laser resonator is collimated (or substantially collimated) in at least one axis using a lens. The lens should have a high radiant intensity efficiency (typically exceeding 50%) with a high numerical aperture (NA).

[0050] According to a further implementation of the above system, the beam deflection mechanism should further have a high radiant intensity efficiency exceeding 50%, and further its center of rotation should be close to the weighted average point of the beam, or close to the maximum intensity point of the beam or the center of the 50% intensity line or 90% intensity line of the beam.

[0051] An overall radiant intensity efficiency of 30% for the transmission / reception / conversion process is a desirable level to make the system energy efficient, but it should be understood that this is limited by the constraints of the available components and environmental conditions, and it should be understood that levels below 30% such as 20% or less are also operable.

[0052] In addition, any of the above systems may include a retroreflector. Also, the gain medium can be electrically or optically excited by a diode. Further, the second bandgap energy can exceed 50% of the first bandgap energy. ​​​​​​​​

[0053] Still other implementations perform a method of transmitting power from a transmitter to a receiver. This method (a) converts a first power into an electromagnetic wave having a frequency between approximately the first overtone of the C-H absorption located at approximately 6940 cm -1 and approximately the second overtone of the C-H absorption located at 8130 cm such that the electromagnetic wave has a radiance of at least 8 kW / m -1 / steradian, and the conversion is performed by using an optical resonator having an end reflector and a gain medium connected to a laser driver that receives the first power, the gain medium having a first bandgap energy of 0.8 eV to 1.1 eV, disposed inside the optical resonator, thermally attached to a cooling 2 system, and configured to amplify the electromagnetic wave passing therethrough and, (b) directing the electromagnetic wave to at least one of a plurality of directions using a beam steering device controlled by a control unit, (c) detecting the collision of the beam with a target having an associated partially transparent surface, wherein an indication associated with the collision causes the control unit to (i) cause a change in the small signal gain of the gain medium, (ii) cause a change in the radiance of the electromagnetic beam, (iii) cause a change in the first power, (iv) change the scan speed of the beam steering device, (v) change the scan position of the beam steering device, and (vi) record the scan position that defines the position of the target, and is utilized by performing at least one of and, (d) light having a second bandgap energy smaller than the first bandgap energy (e) using the light having the second bandgap energy to detect the position of the target, and (f) using the light having the second bandgap energy to perform at least one of (i) causing a change in the small signal gain of the gain medium, (ii) causing a change in the radiance of the electromagnetic beam, (iii) causing a change in the first power, (iv) changing the scan speed of the beam steering device, (v) changing the scan position of the beam steering device, and (vi) recording the scan position that defines the position of the target. wherein an indication associated with the collision causes the control unit to (i) cause a change in the small signal gain of the gain medium, (ii) cause a change in the radiance of the electromagnetic beam, (iii) cause a change in the first power, (iv) change the scan speed of the beam steering device, (v) change the scan position of the beam steering device, and (vi) record the scan position that defines the position of the target, and is utilized by performing at least one of and, (iv) changing the scan speed of the beam steering device, (v) changing the scan position of the beam steering device, and (vi) recording the scan position that defines the position of the target. wherein an indication associated with the collision causes the control unit to (i) cause a change in the small signal gain of the gain medium, (ii) cause a change in the radiance of the electromagnetic beam, (iii) cause a change in the first power, (iv) change the scan speed of the beam steering device, (v) change the scan position of the beam steering device, and (vi) record the scan position that defines the position of the target, and is utilized by performing at least one of (d) light having a second bandgap energy smaller than the first bandgap energy By using a power converter, convert the electromagnetic wave into a second power having a certain voltage. and (e) An inductor, an energy storage device, and an expression

Number

[0054] In such a method, the switch can be switched at a frequency determined by the formula

Number

[0055] In addition, the detection of the beam hitting the target can be performed by either the use in a transmitter for detecting the retroreflective illumination from the target or the use in detecting the illumination of the target using a receiver sensor Thereby, it can be performed by either the use in a transmitter for detecting the retroreflective illumination from the target or the use in detecting the illumination of the target using a receiver sensor Thereby, it can be performed by either the use in a transmitter for detecting the retroreflective illumination from the target or the use in detecting the illumination of the target using a receiver sensor

[0056] Furthermore, in any of the above methods, the second bandgap energy can exceed 50% of the first bandgap energy Thereby, it can be performed by either the use in a transmitter for detecting the retroreflective illumination from the target or the use in detecting the illumination of the target using a receiver sensor

[0057] A system for optical wireless power transmission to at least one power receiving device, the system comprising (i) an optical resonator adapted to emit an optical beam having a plurality of end reflectors (ii) a filter that attenuates radiation at at least one frequency having a wave number in the range of 8,300 cm (ii) a filter that attenuates radiation at at least one frequency having a wave number in the range of 8,300 cm -1 to 12,500 cm -1 and optically communicates with a gain medium including either (a) a semiconductor device or (b) a solid host doped with neodymium ions and optically communicates with a gain medium including either (a) a semiconductor device or (b) a solid host doped with neodymium ions and optically communicates with a gain medium including either (a) a semiconductor device or (b) a solid host doped with neodymium ions positioned inside the optical resonator having a first bandgap energy and thermally attached to a cooling system and configured to amplify the light passing through itself gain medium (iii) a driver configured to supply power to the gain medium and enable control of the small signal gain of the gain medium (iii) a driver configured to supply power to the gain medium and enable control of the small signal gain of the gain medium (iv) a beam steering device configured to direct the optical beam in at least one of a plurality of directions a rudder device, (v) an optical / power converter disposed in the at least one power receiving device for converting the optical beam into electric power having a voltage, the optical / power converter having a second bandgap energy, and an optical / power converter having a second bandgap energy; (vi) a detector configured to give a signal indicating that the optical beam impinges on the optical / power converter, and a detector configured to give a signal indicating that the optical beam impinges on the optical / power converter; (vii) a controller adapted to control at least one of the status of the beam steering device and the driver, the controller receiving a control input signal from at least the detector, and a controller receiving a control input signal from at least the detector; comprising, wherein the optical beam has a radiant intensity of at least 8 kW / m 2 / steradian, and the overall radiant intensity efficiency of transmission between the transmitter and the at least one power receiving device is at least 20%.

[0058] In such a system, the overall radiant intensity efficiency of transmission between the transmitter and the at least one power receiving device should be at least 30%. In such a system, the overall radiant intensity efficiency of transmission between the transmitter and the at least one power receiving device should be at least 30%.

[0059] Furthermore, each of the above-described systems may further include a voltage converter connected to the output of the optical / power converter. In such a case, the voltage converter may be configured to track the maximum power point of the optical / power converter. In addition, the voltage converter may be a DC / DC boost voltage converter. Furthermore, each of the above-described systems may further include a voltage converter connected to the output of the optical / power converter. In such a case, the voltage converter may be configured to track the maximum power point of the optical / power converter. In addition, the voltage converter may be a DC / DC boost voltage converter. Furthermore, each of the above-described systems may further include a voltage converter connected to the output of the optical / power converter. In such a case, the voltage converter may be configured to track the maximum power point of the optical / power converter. In addition, the voltage converter may be a DC / DC boost voltage converter. Furthermore, each of the above-described systems may further include a voltage converter connected to the output of the optical / power converter. In such a case, the voltage converter may be configured to track the maximum power point of the optical / power converter. In addition, the voltage converter may be a DC / DC boost voltage converter.

[0060] Still other implementations may include one of the above-described systems, wherein the resonator includes at least one dielectric mirror. Still other implementations may include one of the above-described systems, wherein the resonator includes at least one dielectric mirror.

[0061] Alternatively, the optical / power converter may be a photovoltaic cell, in which case the photovoltaic cell is II It may include I-V semiconductor materials.

[0062] Further implementation examples may include a system as described above, and may further include an energy storage device that can be a capacitor or a rechargeable battery.

[0063] Still other advantageous implementations may be a system such as the system described above, and may further include an inductor. In such a situation, the inductor may have an inductance between

Number

Number

[0064] Still other systems of the present disclosure may be as described above, and the system is configured to receive information from a power receiving device. This information may include at least one of battery status, device identification, required power, required voltage, and keys.

[0065] Furthermore, any of the systems described above may further include a sensor that determines the temperature of the optical / power converter. In this case, the sensor may be configured to modify the power of the optical beam in response to a change in the temperature of the optical / power converter. The output of the temperature sensor is received by the controller ​ should be

[0066] According to yet other implementations described in the present disclosure, any such system may further include an optical window positioned between the photovoltaic / power converter and the beam steering device. In such a case, the window may have a refractive index of at least 1.5, or at least 1.6, and may be coated with an anti - reflection film. In addition, in such a system, the second bandgap energy should be less than the first bandgap energy.

[0067] Furthermore, the controller should be adapted such that the beam steering device directs the optical beam towards at least one power receiving device. According to yet other implementations of the systems described in the present disclosure, a system for optical wireless power transmission to at least one power receiving device is provided. This system includes

[0068] (i) an optical resonator having a plurality of end reflectors and adapted to emit an optical beam, (ii) a filter that attenuates radiation at at least one frequency having a wave number in the range of 8,300 cm

[0069] to 12,500 cm and optically communicates with a gain medium including either (a) a semiconductor device or (b) a solid host doped with neodymium ions, wherein the gain medium is positioned inside the optical resonator, has a first bandgap energy, and is thermally attached to a cooling system and configured to amplify the light passing through itself, (iii) a power supply configured to supply power to the gain medium and to control the small - signal gain of the gain medium -1 from -1 such that the gain medium is positioned inside the optical resonator, has a first bandgap energy, and is thermally attached to a cooling system and configured to amplify the light passing through itself, and optically communicates with a gain medium including either (a) a semiconductor device or (b) a solid host doped with neodymium ions, wherein the gain medium is positioned inside the optical resonator, has a first bandgap energy, and is thermally attached to a cooling system and configured to amplify the light passing through itself, and is thermally attached to a cooling system and configured to amplify the light passing through itself, and is thermally attached to a cooling system and configured to amplify the light passing through itself, and a gain medium including either (a) a semiconductor device or (b) a solid host doped with neodymium ions, (iii) a power supply configured to supply power to the gain medium and to control the small - signal gain of the gain medium A driver enabling control, (iv) A beam steering device configured to direct the light beam in at least one of a plurality of directions, and, (v) An optical / power converter disposed within the at least one power receiving device and configured to convert the light beam into electric power having a voltage, the optical / power converter having a second bandgap energy, and, and, (vi) A detector configured to provide a signal indicating that the light beam impinges on the optical / power converter, and, (vii) A controller adapted to control at least one of the status of the beam steering device and the driver, the controller receiving at least a control input signal from the detector, and, and, including, wherein the controller is configured to respond to an indication of a safety risk occurring in the system by outputting a command that effects at least one of: (a) causing the driver to change the small-signal gain of the gain medium; (b) changing the emission luminance of the light beam; (c) changing the power supplied by the driver; (d) changing the scan speed of the beam steering device; (e) changing the attitude of the beam steering device; (f) recording a scan attitude that defines the placement of the optical / power converter. The system is configured to respond to an indication of a safety risk occurring in the system by outputting a command that effects at least one of: The terms "position" and "orientation" are understood to mean both the location and the angular orientation at which the beam steering device directs the beam. Further, the driver configured to supply power to the gain medium is also configured to vary the excitation power input to the gain medium or to turn the driver fully on or off.

[0070] The terms "position" and "orientation" are understood to mean both the location and the angular orientation at which the beam steering device directs the beam. Further, the driver configured to supply power to the gain medium is also configured to vary the excitation power input to the gain medium or to turn the driver fully on or off. The terms "position" and "orientation" are understood to mean both the location and the angular orientation at which the beam steering device directs the beam. Further, the driver configured to supply power to the gain medium is also configured to vary the excitation power input to the gain medium or to turn the driver fully on or off. or off. It is understood that the small-signal gain of the gain medium can be controlled by turning it on or off.

[0071] In such a system, the display of safety risks occurring in the system is at least from a signal generated by a detector configured to give a signal indicating that the light beam has collided with the light / electricity converter, and from a signal generated based on the level received by a resonator of a beam reflected from at least one power receiving device.

[0072] All the systems described later may further include a voltage converter connected to the output of the light / electricity converter. Such a voltage converter should be configured to track the maximum power point of the light / electricity converter. In addition, the voltage converter may be a DC / DC boost voltage converter.

[0073] According to a further implementation of such a system, the resonator may include at least one dielectric mirror. Further, the light / electricity converter may be a photovoltaic cell, and such a photovoltaic cell may include III-V semiconductor materials.

[0074] Another implementation of such a system may further include an energy storage device that can be a capacitor or a rechargeable battery. In addition, these may further include an inductor. Such an inductor may have an inductance between

Number

Number

[0075] Furthermore, each such system may be configured to receive information from at least one power receiving device. Such information may include at least one of battery status, device identification, required power, required voltage, and key.

[0076] The system may further include a sensor for determining the temperature of the opto / electric converter. Such a system may be configured to modify the power of the optical beam in response to a change in the temperature of the opto / electric converter. To do this, the output of the temperature sensor should be received by a controller.

[0077] An additional example of such a system may further include an optical window positioned between the photovoltaic opto / electric converter and the beam steering device. Such a window may have a refractive index of at least 1.5, or may have a refractive index of at least 1.6, and may further be coated with an anti-reflection film.

[0078] Finally, in any of the systems described above, the second bandgap energy should be less than the first bandgap energy.

[0079] In many situations, the maximum power radiated by the system is from the safety requirements of the system, from the engineering requirements of the system, from the power requirements of the receiver (which can vary dynamically ) or other problems, it is necessary to limit to prevent exceeding a predetermined maximum value that can be derived. In such a case, when the optical beam exceeds a certain power, the system can reduce the small-signal gain of the gain medium and cause a decrease in the radiance emitted by the system. Therefore, according to yet further implementations, such a system may further be arranged to provide a signal indicative of the power carried by the optical beam before colliding with at least one power receiver device. In such a situation, the driver can be configured to reduce the small-signal gain of the gain medium when the power indication of the power sensor exceeds a threshold. In addition, one important indication of a safety risk is "power loss", that is, an estimate of power not explained by the system. Such power can be lost to the system, but can also be a loss for power emission in a risky manner. When such "power loss" is detected, the system needs to perform various operations to ensure safe operation. Such operations may include reducing the power of the beam, reducing the small-signal gain, reducing the radiance of the system, deflecting the beam, or notifying the user. Therefore, the detector also provides a signal indicating the power received by at least one power receiver device. In this case, at least one of the safety indications may result from the difference between the power indicated by the power sensor and the power indicated by the detector at one of the at least one power receiver device. Subsequently, at least one of the safety indications may occur because the difference exceeds a threshold.

[0080]

[0081]

[0082] Other safety hazard indications may result from a beam intrusion sensor that can be optical or from system stem integrity sensors such as watchdog, interlock, thermistor that may indicate that the system is not safe. In such cases, the system can perform safety operations such as reducing the power of the beam , reducing the small signal gain, reducing the radiance of the system, deflecting the beam, or notifying the user .

[0083] Accordingly, further implementations of the system may include a beam intrusion sensor adapted to detect when an unwanted object enters the light beam. The entry of an unwanted object constitutes an indication of a safety risk. Alternatively and additionally, such a system may further include an enclosure integrity sensor. Here, a warning that the integrity of the enclosure issued by the sensor indicates a safety risk. Such a system may also include a detection device for detecting a deviation operation of at least one important subsystem in the system . A deviation operation constitutes an indication of a safety risk. .

Brief Description of the Drawings

[0084] The present invention will be fully understood and recognized by the following detailed description taken in conjunction with the drawings.

[0085]

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DETAILED DESCRIPTION OF THE INVENTION

[0086] In view of the above considerations, one exemplary implementation of the optical wireless power supply system of the present disclosure is 6940 cm -1 The first overtone of the C-H absorption at and the second overtone of the C-H absorption at 8130 cm -1 And Can be a system tuned to operate between. Such overtone bands are Not well-known bands, do not contain so much chemical information, and result from substantially forbidden quantum mechanical transitions and are only allowed due to complex mechanisms. Therefore, the overtone band provides exactly the broad and weak absorption band preferred for the present application . However, it is known not to be significantly used in analytical chemistry. Due to the broad nature of the band While it is possible to detect various different polymer compositions, the weak absorption allows the system To continue to operate even near organic contaminants and fingerprints. This Thus, these lines are not very useful for typical absorption measurement applications, but this type For It is ideal for SCR. Another advantage of these lines is that there are no general absorption lines positioned directly at the same frequency, and therefore, even if the chemical composition of the material changes, the measurement results are not modified so strongly. Many such harmonic bands are illustrated in the chart of FIG. 12. There are no general absorption lines positioned directly at the same frequency, and therefore, even if the chemical composition of the material changes, the measurement results are not modified so strongly. Many such harmonic bands are illustrated in the chart of FIG. 12. There are no general absorption lines positioned directly at the same frequency, and therefore, even if the chemical composition of the material changes, the measurement results are not modified so strongly. Many such harmonic bands are illustrated in the chart of FIG. 12. There are no general absorption lines positioned directly at the same frequency, and therefore, even if the chemical composition of the material changes, the measurement results are not modified so strongly. Many such harmonic bands are illustrated in the chart of FIG. 12.

[0087] Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. 2 / steradian of radiant intensity is required Electro-optical components operating in that band are lacking and difficult to procure. This is probably because both diode lasers and Diode-Pumped, Solid State (DPSS) lasers are not very efficient at that frequency, and only low-power lasers are currently commercially available. Since lasers with the desired parameters at the preferred frequency are not currently available, a laser suitable for this application must be designed from scratch. It is necessary to design a resonator and a gain medium. It is necessary to construct a laser with a selected frequency and radiant intensity value sufficient to promote a roughly collimated or nearly collimated beam. To achieve good collimation of the beam, a radiant intensity of at least 8 kW / m² / sr is required, and a high-power system for efficient power transmission requires about 800 kW / m² / sr. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. 2 / steradian For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. 2 / steradian) in the future For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle. For a small system operating over a long distance, following the same principle, it will be possible to design a fairly high radiant intensity (up to 10 GW / m² / sr) in the future. Receivers used with a radiant intensity below that level will have to be so large that the system becomes difficult to handle.

[0088] Different mirror settings were used for the resonator. Specifically, good quality metal mirrors made of gold, silver or aluminum were used. These are known to significantly reduce the laser oscillation efficiency. Considerable good results are achieved with dielectric material mirrors . Alternatively, Fresnel mirrors have an advantage in that they are low cost. Other mirrors that can be used are Bragg mirrors (which can be dielectric). The mirrors need to be positioned to form a stable or near-stable resonator, or a resonator in which photons are confined in a certain space by a barrier inside the laser (such as in a fiber or diode laser) . The gain medium needs to be placed in the resonator such that the gain medium is allowed to amplify the beam and resonate inside the resonator, with a radiance of at least 8 kW / m / steradian between the mirrors at a position where this is allowed . If the gain medium can laser oscillate at more than one wavelength, the dielectric mirror can be selected to limit the wavelength to an eigenvalue. Alternatively, a filter can be used 2 to fix the laser oscillation frequency .

[0089] Specifically, it is beneficial if the mirror has a high reflectivity for at least one wavelength between the first overtone of the C-H absorption at 6940 cm and the second overtone of the C-H absorption at 8130 cm .

[0090] Three different approaches can be used for the gain medium -1 . -1 At least one wavelength between the first overtone of the C-H absorption at 6940 cm and the second overtone of the C-H absorption at 8130 cm

[0091] .

[0092] 1. DPSS design

[0093] In a DPSS design, the gain medium can be an Nd-doped YAG crystal. However YVO4 crystals, GGG crystals, and glass are also options for the transparent host. For operation between the first overtone of the C-H band and the second overtone of the C-H band, neodymium is most suitable because Nd has transitions around approximately 7450 cm -1 . Nd ions Typically need to be excited by absorbing radiation from an 808 nm laser diode. However, other wavelengths can also be used. Nd-based gain media tend to laser oscillate at a fairly high frequency unless a filter that blocks transitions around 940 0 cm is added inside the resonator, or unless unwanted radiation from the resonator is extracted. When such a filter is added, laser oscillation starts at 7440 - 7480 cm -1 . Such filter action can be achieved by using a prism or grating instead of a filter, or by appropriate color design of the laser resonator. tends to occur. -1 This filter action can be achieved by using a prism or grating instead of a filter, or by appropriate color design of the laser resonator.

[0094] 2. Semiconductor Laser

[0095] Alternatively, a semiconductor-based design can be proposed. The wavelength of a semiconductor laser can be tuned by modifying the laser oscillation bandgap of the semiconductor used. Semiconductors, specifically III-V types with a bandgap on the order of 1 eV, and more specifically, but not exclusively, quantum dot types, emit light at the desired frequencies of 690 0 cm to 8200 cm 0 cm -1 ~8200 cm -1 . Specifically, 0.8e A bandgap of ~1.1 eV results in good performance and is absorbed, at least in part, by substantially all of the commonly used polymers.

[0096] 3. Various alternative designs, such as Bragg mirrors and / or fiber loop mirrors, may be included Nd-doped fiber lasers can also be used in the systems described in this disclosure. Alternatively, Raman-shifted fiber lasers can also be used.

[0097] During operation, the gain medium heats up and must be cooled to prevent wavelength shift and efficiency degradation. If the gain medium is properly cooled, the excitation power or current can be increased until a beam with a radiance of at least 8 kW / m / steradian 2 is emitted, having a frequency between 6900 cm and 8200 cm -1 . Such a beam can be substantially collimated and is thus attenuated by most organic materials containing polymers that allow detection. Nevertheless, it is not strongly absorbed by contaminants such as fingerprints. -1

[0098] The laser gain medium is typically configured to operate at a temperature below 150 degrees Celsius. If that temperature exceeds a certain level, typically around 250 degrees Celsius, a number of problems can occur.

[0099] First, especially in 3-level and 4-level lasers, the low-level excited states can accumulate, and further, due to the thermal recombination of charge carriers in the semiconductor, the emission efficiency can be significantly reduced.

[0100] Second, soldering of the gain medium may be damaged if such a thermal attachment method is used. It can be damaged.

[0101] Third, a thermal aberration that causes beam degradation may occur.

[0102] Fourth, since the thermal expansion of the laser gain medium can be different from that of its surroundings, mechanical stress, or distortion and fracture of the gain medium can be caused. It can cause mechanical stress, or distortion and fracture of the gain medium.

[0103] For these reasons, especially the gain medium needs to be thermally attached to the cooling system. Typically, the gain medium dissipates 0.1 to 100 W of heat from a surface of 1 mm 2 to 40 mm 2 and emits it. The cooling system of the gain medium needs to have a thermal resistance of less than 200 Kelvin per watt so that the temperature of the gain medium is maintained below 150 degrees. For a system that typically transmits high power generated from a power input exceeding 10 W, the thermal resistance needs to be significantly lower, and in many cases, a thermal resistance of less than 0.05 Kelvin / watt is required. For a system that typically transmits high power generated from a power input exceeding 10 W, the thermal resistance needs to be significantly lower. And in many cases, a thermal resistance of less than 0.05 Kelvin / watt is required.

[0104] The attachment of the cooling system to the surface of the gain medium needs to have a thermal expansion coefficient that matches both the thermal expansion coefficient of the gain medium itself and the thermal expansion coefficient of the front surface of the cooling system. Typically, it is done using a third material such as solder or adhesive. It is typically done using a third material such as solder or adhesive.

[0105] Such a cooling system can typically be a passive heat sink, a heat sink with a fan, a Peltier element connected to a heat sink with or without a fan, or any of a liquid-cooled cooling system. It can be any of a passive heat sink, a heat sink with a fan, a Peltier element connected to a heat sink with or without a fan, or a liquid-cooled cooling system. Alternatively, an independent liquid circulation cooling system based on active circulation by a circulation pump or passive circulation by a heat pipe can also be used. Alternatively, an independent liquid circulation cooling system based on active circulation by a circulation pump or passive circulation by a heat pipe can also be used.

[0106] If the cooling system includes a heat sink with a fan, its thermal resistance is 0.1 degrees Kelvin. It must be less than every watt.

[0107] If the cooling system is a passive heat sink, its thermal resistance is less than 0.3 degrees Kelvin per watt. must be full.

[0108] If the cooling system is a Peltier element, it must generate a temperature difference ΔT of at least 5 degrees. do.

[0109] If the cooling system is an active liquid cooling system, it will cover the entire range of thermal resistances mentioned here. It must be possible to do so.

[0110] Passive heat sinks are preferred in systems designed for low cost and quiet operation. While liquid cooling systems are preferred for high power systems, fan-assisted heating is preferred. A typical system in which the power sink or fluid pump has an electrical output of more than 1 W; and It is used for transmitters having small volumes, such as approximately less than one liter.

[0111] The gain medium is typically driven by a driver, which provides power to the gain medium. However, that power is given as electrical power in the case of some semiconductor gain media, or as a Semiconductor gain media or DPSS systems, or chemical or other forms of energy The amount of power provided by the driver depends on the operating conditions and the level. The saturation gain of the gain medium, on the other hand, generally determines the small signal gain achieved, which determines the laser radiation. is a function of the material selected for the gain medium and ultimately the radiation emitted by the laser. It becomes emission luminance. However, it does not necessarily become a simple linear form. Such a laser driver may have two or more operating states. One is used for power transmission, and the other is for the target exploration, setup, and other functions of the system such as information transmission. Importantly the laser driver creates stable emission under both operating conditions (regarding power and beam parameters ). However, stable operation during power transmission is more important .

[0112] In order to convert the optical beam back to electricity so that useful power is transmitted, an optical / electric power converter, typically a photovoltaic cell, needs to be used. Similar to the laser, a suitable photovoltaic cell tuned to the frequency of the beam used is not generally available as a commercially available component, so a custom battery is required. The bandgap of the photovoltaic semiconductor needs to be slightly smaller than the bandgap of the gain medium used so that the beam frequency is efficiently absorbed by the semiconductor. Otherwise, the conversion efficiency becomes very poor . On the other hand, if the bandgap used is too small, a system with poor efficiency is achieved . Also, the conductor on the photovoltaic cell needs to be tuned to the emission luminance of the beam used . The higher the emission luminance, the thicker the conductor required.

[0113] The bandgap of the laser gain medium needs to be in the range of 0.8 - 1.1 eV, and the bandgap of the photovoltaic cell used needs to be lower than that. A single-junction photovoltaic cell typically generates a voltage of about 60 - 80 % of the bandgap energy divided by the electronic charge, so a single-junction cell tuned to the laser frequency, in the actual system ​ Assuming a few watts of output power required by the mu, typically a very low voltage of 0.3 to 0.8V and typically a high current are brought about. The conductor on the semiconductor needs to be thick enough to carry the generated current without significant loss (e.g., exceeding 5%). Typically, the series resistance of the conductor needs to be less than 1 ohm, and even better, less than 0.1 ohm. The heat generated needs to be efficiently extracted from the photovoltaic cell. Its efficiency generally decreases with temperature.

[0114] This combination of low voltage and high power cannot be easily converted to the high voltage of 3.3 or 5V typically required to charge portable devices. Furthermore, some systems such as communication systems require voltages such as -48V, 12V or 3.8V. The system needs to supply a stable voltage at a level higher than the output voltage predicted from the photovoltaic cell. A typical way to increase the voltage of the photovoltaic cell is to connect the cells in series, as described in U.S. Patent No. 3,370,986 to M.F. Amsterdam et al. entitled "Photovoltaic Series Array Including P / N Cells and N / P Cells". This shows a typical configuration that provides a high voltage while using approximately the same amount of semiconductor without additional components, so it is a typically selected solution. However, this solution is not suitable for the system described in the present application where a laser with a high radiance of 8 kW / m / steradian is used. This is especially because such lasers typically do not have a beam of uniform shape. Furthermore, its beam shape is described in U.S. Patent No. 3,370,986 to M.F. Amsterdam et al. entitled "Photovoltaic Series Array Including P / N Cells and N / P Cells". This shows a typical configuration that provides a high voltage while using approximately the same amount of semiconductor without additional components, so it is a typically selected solution. However, this solution is not suitable for the system described in the present application where a laser with a high radiance of 8 kW / m

[0115] However, this solution is not suitable for the system described in the present application where a laser with a high radiance of 8 kW / m 2 / steradian is used. This is especially because such lasers typically do not have a beam of uniform shape. Furthermore, its beam shape is typically not suitable for the system described in the present application where a laser with a high radiance of 8 kW / m Since it can vary over time, the pointing accuracy can be lower than desired for optimal performance. In such a situation, it is substantially impossible to design a compact and efficient system that illuminates all cells equally. Photovoltaic cells connected in series will not be illuminated uniformly and will not generate the same current. In such cases, the voltage can actually be increased to the desired level, but the current will drop to the current generated by the cell that produces the minimum current, usually the cell that is minimally illuminated. In such a situation, the efficiency is very poor. Therefore, an improved alternative method for increasing the voltage is needed. One way to increase the voltage of a single cell is to charge a capacitor in parallel and then discharge it in series. This method gives good results for low currents, but as the current increases beyond a certain level, the switching time becomes a factor that affects the efficiency.

[0116] The efficiency deteriorates as the switching time increases. When energy is converted to AC using a fast and low-resistance switching mechanism, the AC current is amplified using the combined inductance and then converted back to AC. The increased AC voltage can be converted to DC using a diode bridge and an energy storage device such as a capacitor or battery. Such a system has advantages when it is necessary to increase the voltage by more than 20 times the photovoltaic cell voltage.

[0117] Another advantage of such a system is that switching can be done from the transmitter using a laser, so the receiver The cost and complexity of the device can be reduced. Such a system has disadvantages when the voltage needs to be increased by less than 10 times, or when size and volume limitations are important for the application. Or when it becomes important for the application. It has disadvantages.

[0118] Now, refer to FIG. 13A showing an efficient and simple method of voltage conversion. In the configuration of FIG. 13A, a single inductor can be used together with a low-resistance switching mechanism and an energy storage device to increase the voltage of the photovoltaic cell. In FIG. 13A, the square on the left is the photovoltaic cell, the switch S is a low-resistance switch such as a MOSFET, JFET, BJT, IGBT or pHEMT, the inductance L is connected to the output of the photovoltaic cell, and the capacitor C acts as an energy storage device. In the configuration of FIG. 13A, to increase the voltage of the photovoltaic cell, a single inductor can be used together with a low-resistance switching mechanism and an energy storage device. And the capacitor C acts as an energy storage device. In FIG. 13A, the square on the left is the photovoltaic cell, the switch S is a low-resistance switch such as a MOSFET, JFET, BJT, IGBT or pHEMT, the inductance L is connected to the output of the photovoltaic cell, and the capacitor C acts as an energy storage device. BJT, IGBT or pHEMT, and the inductance L is connected to the output of the photovoltaic cell, and the capacitor C acts as an energy storage device. The following description assumes the use of zero-resistance components for simplicity. Considering the resistance losses, the calculations become complex and will be explained in a later section of the present disclosure. The switching mechanism circulates the inductor between two primary operating phases, namely the charging phase and the discharging phase. In the charging phase, the inductor is connected in parallel with the photovoltaic cell by closing the switch S. During this phase, the inductor is charged by the energy converted by the photovoltaic cell. The increase in inductor energy is given by:

[0119] The following description assumes the use of zero-resistance components for simplicity. Considering the resistance losses, the calculations become complex and will be explained in a later section of the present disclosure. The switch mechanism circulates the inductor between two primary operating phases, namely the charging phase and the discharging phase. In the charging phase, the inductor is connected in parallel with the photovoltaic cell by closing the switch S. During this phase, the inductor is charged by the energy converted by the photovoltaic cell. During this phase, the inductor is charged by the energy converted by the photovoltaic cell. The increase in inductor energy is given by: The increase in inductor energy is given by:

Number

[0120] In the discharging phase, the inductor is connected between the photovoltaic cell and the load by opening the switch S. During this phase, the energy sent from the inductor to the output energy storage device is provided by the decrease in inductor energy. Here, the energy sent from the inductor to the output energy storage device is provided by the decrease in inductor energy.

Number

[0121] The energy sent from the photovoltaic cell to the inductor during this phase is

Number

Number

[0122] In steady-state operation, the energy of the inductor at the end of the cycle is the same as that provided at the beginning of the cycle. This is after substitution the same as that provided at the beginning of the cycle.

Number

Number

[0123] However, in this system, the parasitic characteristics of the components and other aspects may have a significant impact on the conversion operation and efficiency. Therefore, care must be taken to select and use the correct components to allow for the efficient operation of the system. These aspects will be considered one by one below. will be considered one by one below.

[0124] Inductor

[0125] 1. The inductance of the inductor defines the rate of change of the inductor current due to the applied voltage which is given by dI / dt = V / L. Here, dI / dt is the rate of change of the current, V is the voltage applied across the inductor, and L is the inductance . In the context of the current system, V is determined by the gain medium in the transmitter. By selecting different gain media, changes are induced in the photon energy, which subsequently govern the change in the photovoltaic bandgap and thus the change in the photovoltaic voltage. And this requires different inductors and / or switching frequencies. The switching speed must be fast enough for the inductor current to respond to changes in the incident power from the transmitter via the optical / electrical converter, and slow enough to avoid high-amplitude current ripples that contribute to power losses, input voltage ripple, and output voltage ripple. The optimum value of the inductor is such that the ripple current is 20% - 40% of the maximum predicted input current. and must be slow enough to avoid high-amplitude current ripples that contribute to power losses, input voltage ripple, and output voltage ripple. The optimum value of the inductor is such that the ripple current is 20% - 40% of the maximum predicted input current. 20% - 40% of the maximum predicted input current. should be, but the system can operate at 10% to 60%. According to a rigorous analysis of the circuit parameters, to achieve this goal, the value of the inductor measured in henries L must be within the limit

Number

[0126] To successfully incorporate the inductor into a mobile client, the inductance should typically be less than 10 mH. This is an appropriate inductor for the current required to charge the mobile client, and inductors with appropriate volume limitations for portable applications typically fall well below this value. Also, inductors with an inductance that is too small, such as 10 n H, require a high switching frequency that severely limits the availability for other components in the system, such as switches . The switching losses caused by such a high frequency can be higher than the amount of power sent by the photovoltaic cell .

[0127] 2. Series resistance R of the inductor parasitic should be made as low as possible to minimize the conduction power loss. Typically, a value that results in an efficiency reduction of less than 10% is selected ​​​ The series resistance of the inductor, measured in ohms, should be

Number

[0128] 3. For a typical system, the inductor series resistance should be less than 10 Ω. The saturation current of the inductor is usually selected to be higher than the predicted inductor peak current, and is given by. To extract more than 10 mW of power from a single junction photovoltaic cell,

Number

[0129] 4. For reliable operation, the inductor is rated for a current higher than the predicted maximum input current. To extract more than 10 mW of power from a single junction photovoltaic cell, the inductor rated current should be higher than 10 mW / 0.8 v = 12.5 mA. rated current should be higher than 10 mW / 0.8 v = 12.5 mA.

[0130] Switching mechanism

[0131] 1. The switching mechanism is usually made from two or more devices. The first device, the main input switch, when conducting, sets the inductor to the charging phase. The second device connects a load or an output energy storage device to the inductor during the discharge phase, and A diode (Figure 13A) or a switch that has a function to release the connection during the charging phase can be either one of them.

[0132] 2. The switching mechanism should have a low switch node capacitance to minimize switching losses.

Number

Number

[0133] 3. In a typical system, the switch node capacitance is less than 100 nF and more than 10 pF.

[0134] 4. The series resistance of the main switch that connects the inductor to the ground or connects the optical / power converter to the inductor at the switch node should be less than

Number

[0135] Energy storage device

[0136] 1. The energy storage device can be either a capacitor or a battery or both.

[0137] 2. The energy storage device is required to maintain the output voltage during the charging phase when the inductor is disconnected from the output. The capacitance of the storage device should be such that the switch ​​It is selected as follows based on the switching frequency, laser power, and the desired output ripple voltage. Here, ΔV

Number

[0138] 3. The energy storage device can also supply power to the load while the optical path is temporarily interrupted. For uninterrupted power supply, the energy storage device should store at least an amount of energy equal to the minimum operating output power (P ) multiplied by the interruption time interval (T ). When a capacitor is used as the energy storage device, the capacitance should be greater than OUT_MIN INT

Number

Number

[0139] In some cases, the capacitor serves as the energy storage device for the client application. In such cases, the client application can be designed without any secondary energy storage device (the conventionally used battery equipped in a mobile device ). ) . The energy storage device of the system described in this specification It is necessary to store sufficient energy to supply the power required by the client device until the next charging event. In such a case, a supercapacitor having a capacitance of at least 0.5 F and exceeding 10 F can be used. In other cases, that is, when the power requirement of the client device is low, or when there is an independent energy storage device such as a battery installed inside the device, or when the device does not need to operate when there is no power supply, the capacitor used typically exceeds 1 F by more than ten times. When a rechargeable battery is used as the energy storage device, it follows the same logic as the above capacitor, and the battery is only used as a voltage regulating means but not as a means to maintain power supply to the client device between charging events. In this case, it is advantageous for the energy capacity of the battery to be up to 100 times the energy supplied during 100 cycles of the switch (typically less than 0.1 Wh). This level is determined according to the volume equivalent and cost efficiency of the battery. On the other hand, when the battery is also used to supply power to the client device between charging events, its capacity must be at least large enough to store the energy required by the client device between charging events (typically exceeding 0.1 Wh in the case of a cellular phone). The battery also has volume limitations according to the product for which it is intended. That is, when the battery of a product having a certain volume V is incorporated outside the device, it is typically limited to several times the volume of the device, that is, up to 3V. As an example of this rule of thumb, a battery used to supply power to a cellular phone with a volume of 100 cc typically has a volume of 300 cc. It is necessary to store sufficient energy to supply the power required by the client device until the next charging event. In such a case, a supercapacitor having a capacitance of at least 0.5 F and exceeding 10 F can be used. In other cases, that is, when the power requirement of the client device is low, or when there is an independent energy storage device such as a battery installed inside the device, or when the device does not need to operate when there is no power supply, the capacitor used typically exceeds 1 F by more than ten times. In other cases, that is, when the power requirement of the client device is low, or when there is an independent energy storage device such as a battery installed inside the device, or when the device does not need to operate when there is no power supply, the capacitor used typically exceeds 1 F by more than ten times. When a rechargeable battery is used as the energy storage device, it follows the same logic as the above capacitor, and the battery is only used as a voltage regulating means but not as a means to maintain power supply to the client device between charging events. In this case, it is advantageous for the energy capacity of the battery to be up to 100 times the energy supplied during 100 cycles of the switch (typically less than 0.1 Wh). This level is determined according to the volume equivalent and cost efficiency of the battery. On the other hand, when the battery is also used to supply power to the client device between charging events, its capacity must be at least large enough to store the energy required by the client device between charging events (typically exceeding 0.1 Wh in the case of a cellular phone). When a rechargeable battery is used as the energy storage device, it follows the same logic as the above capacitor, and the battery is only used as a voltage regulating means but not as a means to maintain power supply to the client device between charging events. In this case, it is advantageous for the energy capacity of the battery to be up to 100 times the energy supplied during 100 cycles of the switch (typically less than 0.1 Wh). This level is determined according to the volume equivalent and cost efficiency of the battery. On the other hand, when the battery is also used to supply power to the client device between charging events, its capacity must be at least large enough to store the energy required by the client device between charging events (typically exceeding 0.1 Wh in the case of a cellular phone). In this case, it is advantageous for the energy capacity of the battery to be up to 100 times the energy supplied during 100 cycles of the switch (typically less than 0.1 Wh). This level is determined according to the volume equivalent and cost efficiency of the battery. On the other hand, when the battery is also used to supply power to the client device between charging events, its capacity must be at least large enough to store the energy required by the client device between charging events (typically exceeding 0.1 Wh in the case of a cellular phone). This level is determined according to the volume equivalent and cost efficiency of the battery. On the other hand, when the battery is also used to supply power to the client device between charging events, its capacity must be at least large enough to store the energy required by the client device between charging events (typically exceeding 0.1 Wh in the case of a cellular phone). On the other hand, when the battery is also used to supply power to the client device between charging events, its capacity must be at least large enough to store the energy required by the client device between charging events (typically exceeding 0.1 Wh in the case of a cellular phone). On the other hand, when the battery is also used to supply power to the client device between charging events, its capacity must be at least large enough to store the energy required by the client device between charging events (typically exceeding 0.1 Wh in the case of a cellular phone). In this case, it is advantageous for the energy capacity of the battery to be up to 100 times the energy supplied during 100 cycles of the switch (typically less than 0.1 Wh). This level is determined according to the volume equivalent and cost efficiency of the battery. On the other hand, when the battery is also used to supply power to the client device between charging events, its capacity must be at least large enough to store the energy required by the client device between charging events (typically exceeding 0.1 Wh in the case of a cellular phone). The battery also has volume limitations according to the product for which it is intended. That is, when the battery of a product having a certain volume V is incorporated outside the device, it is typically limited to several times the volume of the device, that is, up to 3V. That is, when the battery of a product having a certain volume V is incorporated outside the device, it is typically limited to several times the volume of the device, that is, up to 3V. That is, when the battery of a product having a certain volume V is incorporated outside the device, it is typically limited to several times the volume of the device, that is, up to 3V. As an example of this rule of thumb, a battery used to supply power to a cellular phone with a volume of 100 cc typically has a volume of 300 cc. is limited to less than. Such batteries typically have a capacity of less than 300 Wh due to the limitations described above.

[0140] The circuit in FIG. 13A is not the only possible topology. FIG. 13B shows a different design that can achieve similar performance characteristics. The roles, constraints, and predicted values of the components for FIG. 13B are the same as those listed for the circuit in FIG. 13A. The primary difference is that the positive and negative terminals of the output voltage are reversed.

[0141] In some applications, it is preferred to place the energy storage device inside the device for which the received power is intended to be used. In other applications, specifically in applications where short-term operation is expected and regulated voltage is not required, the energy storage device can even be eliminated.

[0142] Point of adjustment

[0143] The power output of a photovoltaic cell depends on the incident optical power and the load applied to it. Since the optimal load conditions result in the maximum output power from the photovoltaic cell, the control mechanism of the voltage converter needs to adjust the load point. The control mechanism is designed to maintain a constant voltage between the cell terminals known as the maximum power operating point for most conditions, or to track the maximum power operating point by measuring the cell output power under any operating condition and searching for the optimal cell voltage. The first approach is simple, and the second approach is more power efficient.

[0144] ​​​​​​​​​​​​​ The generated laser beam needs to be directed towards the receiver. To direct the beam towards the receiver it is necessary to use a beam steering device. Some beam steering sub systems that can be used include movable mirrors, movable lenses, electro-optical modulators, magneto-optical modulators, a set of motors that move the entire transmitter system in one or more directions, or any other suitable beam deflecting device .

[0145] The beam steering device needs to be controlled by a controller, most preferably by the same controller that is used to control the laser driver.

[0146] The beam steering device is configured to direct a beam exceeding 8 kW / m 2 / steradian in any of a certain number of directions.

[0147] The damage threshold of the beam steering device needs to be able to withstand the radiant intensity of the beam.

[0148] For example, when using a focusing mechanism with an aperture ratio of 0.5 to focus the beam on a mirror, the mirror needs to withstand a power density of at least 6.7 kW / m 2 for a beam of 8 kW / m 2 / steradian. When a beam with a high radiant intensity is used, the mirror needs to be selected to have a correspondingly high damage threshold.

[0149] Figure 14 shows the power reflected by the mirror per square meter when a beam of 8 kW / m 2 / steradian is focused, as a function of the aperture ratio. When a beam with a high radiant intensity is used When used, the power reflected by the mirror increases correspondingly in a linear manner.

[0150] Since the beam is non-uniform, "hot spots" can be generated that sometimes have a radiant luminance ten times that of the beam average.

[0151] Therefore, the mirror should have a damage threshold of at least the same size as that shown in FIG. 14, preferably at least ten times the scale adjusted to the actual beam radiant luminance and numerical aperture on the mirror.

[0152] Typically, there is a determined optical front near the photovoltaic cell and located between the photovoltaic cell and the transmitter. The beam enters the receiver through the optical front, which is required to protect the typically delicate structure of the photovoltaic cell and often matches the external design of the device in which the power receiver is integrated. The front has a film that protects against scratches, such as Corning's Gorilla Glass (registered trademark), or is treated to withstand scratches well. The front is also treated to reduce the level of contamination such as fingerprints and dust that can adhere, or to reduce optical effects, or can be coated with an anti-reflection film that reduces the level of reflected light. The front of the photovoltaic cell can also be coated. In some cases, the front becomes part of the structure of the photovoltaic cell itself or is coated on the photovoltaic cell.

[0153] During some situations, the amount of reflection from the surface can be reduced to below the safety threshold by selecting an anti-reflection film with very low reflection. In case of spilled liquid or finger ​​​​​​​​​​​​​If the film is contaminated or covered by any of the patterns, such an antireflection film loses its effect of reducing the reflection amount, and typically 3-4% of the incident light is reflected in the direction of poor control. When such reflection is reflected in a divergent mode, its power density soon decreases to a safe level. However, if the reflection is focused by chance, the power density can increase to a dangerous level. For this reason, it is important that the ROC (Radius Of Curvature) of such a surface does not become less than a predetermined value at any point. Generally, since the reflection from the surface is intended to be only a small portion of the incident light, regardless of the nature or shape of the curvature of the surface, the risk of any intentional beam reflection is reduced. The level of the reflected light can be variable. This is because even for approximately 4% reflection from an untreated glass surface, if a layer of foreign contaminants on the surface causes an increased reflectivity, it can increase. However, it is predicted that the reflection will not exceed 20%, and generally less than 4% of the untreated glass, as in the case of a typical AR-coated glass with a reflectivity of 0.1% or much lower. Therefore, the surface is described in this disclosure as having the property of reflecting a small portion of the incident light and is thus recited in the claims. This specification is used to mean less than 20% of the incident light, generally less than 4% of the untreated glass. Here, referring to FIGS. 15A to 15C which schematically illustrate a method of avoiding the above-mentioned dangerous reflection even for a small portion of the incident light that can be reflected from the surface. FIG. 15A shows a concave surface of the surface. Regardless of the nature or shape of the curvature of the surface, the risk of any intentional beam reflection is reduced. The level of the reflected light can be variable. This is because even for approximately 4% reflection from an untreated glass surface, if a layer of foreign contaminants on the surface causes an increased reflectivity, it can increase. However, it is predicted that the reflection will not exceed 20%, and generally less than 4% of the untreated glass, as in the case of a typical AR-coated glass with a reflectivity of 0.1% or much lower. Therefore, the surface is described in this disclosure as having the property of reflecting a small portion of the incident light and is thus recited in the claims. This specification is used to mean less than 20% of the incident light, generally less than 4% of the untreated glass. Here, referring to FIGS. 15A to 15C which schematically illustrate a method of avoiding the above-mentioned dangerous reflection even for a small portion of the incident light that can be reflected from the surface. FIG. 15A shows a concave surface of the surface. Regardless of the nature or shape of the curvature of the surface, the risk of any intentional beam reflection is reduced. The level of the reflected light can be variable. This is because even for approximately 4% reflection from an untreated glass surface, if a layer of foreign contaminants on the surface causes an increased reflectivity, it can increase. However, it is predicted that the reflection will not exceed 20%, and generally less than 4% of the untreated glass, as in the case of a typical AR-coated glass with a reflectivity of 0.1% or much lower. Therefore, the surface is described in this disclosure as having the property of reflecting a small portion of the incident light and is thus recited in the claims. This specification is used to mean less than 20% of the incident light, generally less than 4% of the untreated glass. Here, referring to FIGS. 15A to 15C which schematically illustrate a method of avoiding the above-mentioned dangerous reflection even for a small portion of the incident light that can be reflected from the surface. FIG. 15A shows a concave surface

[0154] Here, referring to FIGS. 15A to 15C which schematically illustrate a method of avoiding the above-mentioned dangerous reflection even for a small portion of the incident light that can be reflected from the surface. FIG. 15A shows a concave surface of the surface. shows the situation where the surface is a concave surface, FIG. 15B shows the situation where the surface is a convex surface, and FIG. 15C shows the situation where the surface is a diffused surface In FIG. 15A, an incident beam 110 having a radiance of at least 8 kW / m 2 / steradian is directed towards a photovoltaic cell 112 and passes through a front surface 111 which can be the front surface of the photovoltaic cell The front surface 111 reflects a certain degree of the beam 110 and generates a focused beam 113 having a focus 114 at a certain distance from the surface To ensure that the focus 114 is not dangerous for the skin or other objects, the radius of curvature (ROC) of the surface 111 should be such that the beam is focused with a low numerical aperture as in FIG. 15A or defocused as in FIG. 15B or diffused as in FIG. 15C. To achieve these limitations, when the surface is concave as seen from the transmitter towards the photovoltaic cell as in FIG. 15A its ROC should be greater than 1 cm and typically greater than 5 cm when a high power optical system with light above 0.5 W is used. Alternatively the ROC of the surface can be negative as in FIG. 15B, but the ROC should not be in the range of 0 to 1 cm. These limitations ensure that the reflected light beam either has a virtual focus, i.e., is associated with a diverging reflected beam or the focus is at least 1 cm in front of the surface. As a result, the risk caused by the focus is significantly reduced. The surface may also have a large number of regions with small curvatures resulting in a diffused surface as in FIG. 15C. This reduces the risk of dangerous foci If the ROC is greater than 1 cm and typically greater than 5 cm when a high power optical system with light above 0.5 W is used Alternatively, the ROC of the surface can be negative as in FIG. 15B, but the ROC should not be in the range of 0 to 1 cm. These limitations ensure that the reflected light beam either has a virtual focus, i.e., is associated with a diverging reflected beam or the focus is at least 1 cm in front of the surface. As a result, the risk caused by the focus is significantly reduced. The surface may also have a large number of regions with small curvatures resulting in a diffused surface as in FIG. 15C. This reduces the risk of dangerous foci ensuring that either the focus is virtual, i.e., associated with a diverging reflected beam, or the focus is at least 1 cm in front of the surface As a result, the risk caused by the focus is significantly reduced. The surface may also have a large number of regions with small curvatures resulting in a diffused surface as in FIG. 15C. This reduces the risk of dangerous foci ​​​​​​​​​​​​It helps to significantly reduce κ. In such a case, the radius of curvature of each sub-section of the surface can be less than 1 cm without causing a focus. Further, if the surface is divided into multiple zones, each zone can have a small curvature. The system should also be able to direct the power beam towards the photovoltaic cell so that the power beam is blocked by the photovoltaic cell and not directed towards any dangerous area in order to operate safely. To achieve this, the detector needs to be positioned to give an indication of the beam collision to the receiver. Such a detector is typically positioned at the receiver,

[0155] but a configuration where such a detector is placed at the transmitter is also possible. In this case, the detector needs to respond to the phenomenon caused by the impact of the beam on the receiver. Such a transmitter-related system can include image acquisition and the processing of optical information such as the reflection of the beam from the barcode printed on the receiver received from the receiver. As a result, the transmitter can detect the illumination pattern of the barcode. Reflections from a single or multiple retroreflectors or an array or pattern thereof are positioned at the receiver, and such reflections can be detected at the transmitter by any of image processing, retroreflectometry, or measurement of the coherence effect of the reflection. The detector can be a current or voltage sensor positioned at the receiver, a photodiode in the receiver or transmitter, or an imaging device that can be present in either the transmitter or receiver. A retroreflector near the photovoltaic cell can also be used in combination with an additional detector that detects the light reflected from the retroreflector at the transmitter. The detector needs to be positioned at the receiver. In this case, the detector needs to respond to the phenomenon caused by the impact of the beam on the receiver. Such a transmitter-related system can include image acquisition and the processing of optical information such as the reflection of the beam from the barcode printed on the receiver received from the receiver. As a result, the transmitter can detect the illumination pattern of the barcode. Reflections from a single or multiple retroreflectors or an array or pattern thereof are positioned at the receiver, and such reflections can be detected at the transmitter by any of image processing, retroreflectometry, or measurement of the coherence effect of the reflection. The detector can be a current or voltage sensor positioned at the receiver, a photodiode in the receiver or transmitter, or an imaging device that can be present in either the transmitter or receiver. A retroreflector near the photovoltaic cell can also be used in combination with an additional detector that detects the light reflected from the retroreflector at the transmitter. Reflections from a single or multiple retroreflectors or an array or pattern thereof are positioned at the receiver, and such reflections can be detected at the transmitter by any of image processing, retroreflectometry, or measurement of the coherence effect of the reflection. The detector can be a current or voltage sensor positioned at the receiver, a photodiode in the receiver or transmitter, or an imaging device that can be present in either the transmitter or receiver. A retroreflector near the photovoltaic cell can also be used in combination with an additional detector that detects the light reflected from the retroreflector at the transmitter. The detector can be a current or voltage sensor positioned at the receiver, a photodiode in the receiver or transmitter, or an imaging device that can be present in either the transmitter or receiver. A retroreflector near the photovoltaic cell can also be used in combination with an additional detector that detects the light reflected from the retroreflector at the transmitter. .

[0156] When the detector detects a beam of light impinging on the photovoltaic cell, it transmits a signal in accordance with the system controller. When the detector is at the receiver, such signaling can be done wirelessly using a communication channel that can be RF, IR, visible light, UV, modulation of the beam, TCP / IP, or sound. The system controller is typically located at the transmitter, but may also be located in a main control unit that may also exist on a computer network from the transmitter. When the controller receives the signal, it responds by doing at least one of the following: (a) changing the state of the laser driver. (b) changing the operating characteristics of the beam steering device, such as the direction to which the beam is directed and the speed at which such direction is changed. Here, refer to FIG. 16, which is a schematic diagram showing a detailed description of the complete system. The system includes a transmitter 21 and a receiver 22. Generally, the transmitter and the receiver are arranged to be remote from each other, but in FIG. 16, for convenience, they are shown as being close to each other. The beam 15 transfers power from the transmitter 21 to the receiver 22. At the receiver 22, the front surface 7 reflects a small portion of the incident beam 15 as the reflected beam 16, while diffusing the beam or creating a virtual focus behind the front surface 7 or a real focus at least 1 cm in front of the surface 7. After transmission through the at least partially transparent surface 7, the beam 15 impinges on the optical / power converter 1. The optical / power converter 1 can be encapsulated in a package that can have a front window that can be the surface 7 or a separate window. This can also be the interface with air or an adhesive or glass around it.

[0157] The system includes a transmitter 21 and a receiver 22. Generally, the transmitter and the receiver are arranged to be remote from each other, but in FIG. 16, for convenience, they are shown as being close to each other. The beam 15 transfers power from the transmitter 21 to the receiver 22. At the receiver 22, the front surface 7 reflects a small portion of the incident beam 15 as the reflected beam 16, while diffusing the beam or creating a virtual focus behind the front surface 7 or a real focus at least 1 cm in front of the surface 7. After transmission through the at least partially transparent surface 7, the beam 15 impinges on the optical / power converter 1. The optical / power converter 1 can be encapsulated in a package that can have a front window that can be the surface 7 or a separate window. This can also be the interface with air or an adhesive or glass around it.

[0158] At the receiver 22, the front surface 7 reflects a small portion of the incident beam 15 as the reflected beam 16, while diffusing the beam or creating a virtual focus behind the front surface 7 or a real focus at least 1 cm in front of the surface 7. After transmission through the at least partially transparent surface 7, the beam 15 impinges on the optical / power converter 1. The optical / power converter 1 can be encapsulated in a package that can have a front window that can be the surface 7 or a separate window. This can also be the interface with air or an adhesive or glass around it. After transmission through the at least partially transparent surface 7, the beam 15 impinges on the optical / power converter 1. The optical / power converter 1 can be encapsulated in a package that can have a front window that can be the surface 7 or a separate window. This can also be the interface with air or an adhesive or glass around it.

[0159] The optical / power converter 1 can be encapsulated in a package that can have a front window that can be the surface 7 or a separate window. This can also be the interface with air or an adhesive or glass around it. This can also be the interface with air or an adhesive or glass around it. ​It may be coated to have an external surface adapted to function. Typical In a configuration, the photo / electric power converter 1 is typically a junction of semiconductor layers where conductors are deposited and can be. In many embodiments, the surface 7 is coated on one of these semiconductor layers or becomes the external surface of that one.

[0160] The signaling detector 8 indicates that the beam 15 is hitting the photovoltaic cell 1 and transmits that information to the controller 13 located in the transmitter 21 in this example of the system. The control signal is transmitted to the detector 24 in the transmitter via the link 23.

[0161] The power converter 1 has a bandgap E8 and typically provides a voltage of 0.35 to 1.1 V. However, the use of multi-junction photovoltaic cells provides even higher voltages. The power flows from the photovoltaic cell 1 through the conductors 2a and 2b having low resistance to the inductor 3. The inductor 3 stores a part of the energy flowing through itself in the magnetic field.

[0162] The automatic switch 4 is typically a MOSFET transistor connected to a control circuit (not shown in FIG. 16) and switches between alternating states so that current is allowed to flow through the inductor 3 to ground during the first part of the time and the inductor is allowed to radiate its stored magnetic energy as a current at a voltage higher than that of the photovoltaic cell during the second part of that time. The current passes through the diode 5 and then flows to the load 6 where the power can be used.

[0163] The automatic switch 4 operates at a fixed frequency or is controlled from the transmitter or by the client load operates at a variable frequency and / or duty cycle and / or waveform controlled from it, or based on the current, voltage or temperature in the load, or the current, voltage or temperature in the automatic switch 4, or based on the current, voltage or temperature radiated by the photo / electricity converter 1, or based on some

[0164] The receiver can be directly connected to the load 6 as shown in FIG. 16. Or, the load 6 is external to the receiver, or another device such as a cellular phone or other power-consuming device, and can be connected using a socket such as USB / Micro-USB / Lightning (registered trademark) / USB Type-C.

[0165] In most cases, there is also an energy storage device such as a capacitor or battery connected in parallel with the load 6, or the load 6 can include an energy storage device such as a capacitor or battery.

[0166] The transmitter 21 generates a beam 15 and directs it towards the receiver 22. In the first operating mode, the transmitter 21 searches for the presence of the receiver 22. This is done by using a scan beam, or detecting the receiver using communication means such as RF, light, IR light, UV light or sound, or using a camera to detect visual indicators of the receiver such as a retroreflector or retroreflective structure, barcode, high-contrast pattern or other visual indicator. Once a rough position is found, the beam 15 typically scans the It collides with the photocell 1. When the beam 15 collides with the photocell 1, the detector 8 detects it and sends a signal to the controller 13 accordingly.

[0167] The controller 13 instructs the laser driver 12 to change the power P to the input to the gain medium 11 and / or instructs the mirror 14 to change either its scan speed or direction to direct the beam to that position or hold that position and change the scan step speed in response to such a signal, either or both of which. When the gain medium 11 receives a different power P from the laser power supply 12, its small-signal gain, i.e., the gain received when a single photon crosses the gain medium and there are no other photons crossing the gain medium simultaneously changes. When photons directed in the direction between the rear mirror 10 and the output coupler 9 pass through the gain medium 11, more photons are radiated in the same direction as the direction of the beam 15, and optical resonance occurs between the rear mirror 10 and the output coupler 9.

[0168] The output coupler 9 operates at least in part in the spectral range between the first overtone of the C-H absorption at 6940 cm -1 and the second overtone of the C-H absorption at 8130 cm and typically consists of alternating layers of different refractive index materials, typically -1 deposited on a substrate that is typically glass, plastic, or the surface of the gain medium 11, a multilayer dielectric or a semiconductor film. Alternatively, Fresnel reflection can be used if the gain medium can provide a sufficiently small signal gain or has a sufficiently high refractive index. Standard metal mirrors can also be used. If the gain medium is a semiconductor or fiber amplifier, the Bragg reflection can be used. reflection can be used. Standard metal mirrors can also be used. If the gain medium is a semiconductor or fiber amplifier, the Bragg reflection can be used. ​​A dog reflector can also be used. The output coupler 9 also transmits one part of the light and extracts the other part of the light from the wave traveling forward inside the resonator. Typically a third part is also extracted from the wave propagating backward inside the resonator by a beam extractor such as a semi-transparent optical component which can consist of a high-reflectivity mirror combined with.

[0169] The rear reflector 10 should be a high-reflectivity mirror, but a small amount of light leaks backward and is used for monitoring rings or other purposes and is at 6940 cm -1 the first overtone of the C-H absorption at and 81 30 cm -1 at least a portion of the spectrum between the second overtone of the C-H absorption at and can operate in. Typically, it can be constructed from alternating layers of different refractive index materials deposited on a substrate, which is usually glass, metal or plastic. Alternatively, if the gain medium is small enough to provide sufficient signal gain, Fresnel reflection can also be used. Standard metal mirrors can also be used. If the gain medium is a semiconductor or fiber amplifier , a Bragg reflector can also be used.

[0170] The gain medium 11 amplifies the radiation between the first overtone of the C-H absorption at 6940 cm -1 and the second overtone of the C-H absorption at 8130 cm -1 . However, it does not necessarily cover the entire range of this spectrum . This is such that when excited by the laser driver 12 with power P , it can send a small-signal gain greater than the loss caused by the output coupler 9. The region, field of view, and damage threshold are at least 8 kW / m / steradian / (1 2 -R) must be made large enough to maintain the beam. Here, R is the reflectivity of the output coupler 9 which is a semiconductor material having a band gap of 0.8 to 1.1 eV of a transparent host material doped with Nd ions, or other structures capable of simulating radiation in the spectral range from which the gain medium 11 can be composed. The gain medium 11 is positioned in the optical line of sight from the rear reflector 10 to the output coupler 9, and thus, resonance of the radiation reflected by the rear reflector 10 between the rear reflector 10 and the output coupler 9 through the gain medium 11 is allowed

[0171] For a typical implementation where the gain medium 11 is a semiconductor having a band gap of 0.8 to 1.1 eV, it is preferably attached to a heat extraction device and can be excited electrically or optically by the laser driver 12

[0172] In a typical implementation where the gain medium 11 is a transparent host such as YAG, YVO4, GGG, or glass or ceramics doped with Nd ions, in this case, the gain medium 11 preferably optically communicates with a filter to extract radiation near 9400 cm -1

[0173] The beam steering device 14 is shown to be controlled by the controller 13. This can deflect the beam 15 in multiple directions. Its area must be made large enough so that substantially most of the beam 15 is included even when tilted to the maximum operating tilt angle For a simple 2D example. If the beam 15 is collimated with a 5 mm diameter (1 / e 2 ​​​​​​​​​​​​a Gaussian beam of (diameter), and when the beam steering device is a single round gimbal mirror centered on the beam center, and when the maximum tilt required for the mirror is 30 degrees and assuming that the beam steering device 14 has no other openings, if the mirror has a 5 mm diameter similar to the beam, it will have an approximate 13% loss at normal incidence of the beam, while having an approximate 60% loss at a 60-degree tilt angle. This severely degrades the performance of the system. This power loss is illustrated in the graph of Figure 17. At the start of operation, the controller 13 commands the laser driver 12 and the mirror 14 to perform a search operation. This is done by directing the beam 15 in a general direction where the receiver 22 is likely to be found by operating the laser driver 12 in the first state. For example, if the transmitter is mounted in a corner of the ceiling of a room, the scan is performed downward and between two adjacent walls of the room. When the beam 15 hits the receiver 22 including the optical / electric power converter 1, the detector 8 sends a signal to, for example, the controller 13. Until such a signal is received, the controller 13 commands the beam steering unit 14 to direct the beam 15 in other directions to search for the receiver. When such a signal is received from the detector 8, the controller 13 commands the beam steering unit 14 to stop or slow down the scan and lock onto the receiver, and instructs the laser driver 12 to increase the power emission. Alternatively, the controller 13 can recognize the position of the receiver 22 and return there at a later stage. When the laser driver 12 increases its power emission, the small-signal gain of the gain medium 11 increases.

[0174] At the start of operation, the controller 13 commands the laser driver 12 and the mirror 14 to perform a search operation. This is done by directing the beam 15 in a general direction where the receiver 22 is likely to be found by operating the laser driver 12 in the first state. For example, if the transmitter is mounted in a corner of the ceiling of a room, the scan is performed downward and between two adjacent walls of the room. When the beam 15 hits the receiver 22 including the optical / electric power converter 1, the detector 8 sends a signal to, for example, the controller 13. Until such a signal is received, the controller 13 commands the beam steering unit 14 to direct the beam 15 in other directions to search for the receiver. When such a signal is received from the detector 8, the controller 13 commands the beam steering unit 14 to stop or slow down the scan and lock onto the receiver, and instructs the laser driver 12 to increase the power emission. Alternatively, the controller 13 can recognize the position of the receiver 22 and return there at a later stage. When such a signal is received from the detector 8, the controller 13 commands the beam steering unit 14 to stop or slow down the scan and lock onto the receiver, and instructs the laser driver 12 to increase the power emission. Alternatively, the controller 13 can recognize the position of the receiver 22 and return there at a later stage. When the laser driver 12 increases its power emission, the small-signal gain of the gain medium 11 increases. When the laser driver 12 increases its power emission, the small-signal gain of the gain medium 11 increases.

[0175] When the laser driver 12 increases its power emission, the small-signal gain of the gain medium 11 increases. As a result, the beam 15 carries a large amount of power and power transmission starts. When the detector 8 detects a power loss greater than the threshold value, the controller 13 typically instructs the laser driver 12 to change its state by reducing the power to maintain the required safety level. The threshold value is predetermined or set dynamically and is typically at a level representing a significant portion of the maximum allowable exposure level and is typically greater than the system noise index. These conditions suggest that the beam 15 is no longer accurately directed at the optical / power converter 1, or that some object has entered the path of the beam, or that a malfunction has occurred. Other indications of safe operation, such as a display from the user interface or API regarding the safety of the transmission, or a display of safe operation from a second safety system, may cause the controller to instruct an increase in power to compensate for the power loss to the laser. The controller 13 can also instruct the beam steering assembly 14 to perform a search operation again.

[0176] There are two different stages in the search operation. First, a coarse search is performed by using a possible camera to find a visual pattern, find a retroreflector, find a high-contrast image, find a response signal from the receiver, or find other indications, or by using the scan characteristics of the beam steering section 14. Thus, a list of potential positions where the receiver can be found can be generated. The second stage is a fine search. Here, the beam steering mirror 14 directs the beam 15 at a small area until the detector 8 sends a signal indicating that the beam 15 is colliding with the optical / power converter 1.

[0177] Refer to FIG. 18, which shows an example of a cooling system for the gain medium 11 of the system of FIG. 16. The reflectors 9, 10 are shown as separate optical elements, but it should be understood that one or both of them can be directly coated on the end face of the gain medium to simplify the system. The gain medium 11 converts the power received from the laser driver 12 into both heat and photons, and when the gain medium is heated until it exceeds a certain temperature, typically the system performance deteriorates. For this reason, the gain medium 11 is attached to the heat sink 34 using a heat-conductive solder 33 with low thermal resistance, which is a preferred bonding agent. The bonding agent 33 can also be a conductive adhesive. The bonding agent 33 can have a coefficient of thermal expansion between the coefficient of thermal expansion of the gain medium 11 and the coefficient of thermal expansion of the heat sink 34. The heat sink 34 is typically a metal heat sink with low thermal resistance, and is equipped with fins to increase the surface area, or an external fluid pump system such as a fan or a liquid pump 35. Refer to FIG. 19 here. This is a schematic diagram that shows a detailed description of the system of FIG. 16 and further incorporates a safety system 31 configured and operable according to the methods and systems described in this application. In FIG. 19, it is shown as a separate module to indicate the additional inputs provided, but the safety system can be incorporated into the controller 13, which is generally described and claimed as such. As described above, the system includes a transmitter 21 and a receiver 22.

[0178] Generally, the transmitter and the receiver are arranged remotely from each other, but for convenience, they are shown close to each other as shown in FIG. 19. The beam 15 transfers power from the transmitter 21 to the receiver 22.

[0179] In receiver 22, front face 7 reflects a small portion of incident beam 15 as reflected beam 16 while diffusing the beam or creating a virtual focus behind front face 7 or a real focus at least 1 cm in front of surface 7. After transmission through at least partially transparent surface 7, beam 15 impinges on a light / electricity converter 1 having a semiconductor layer with thickness T and a constant absorption coefficient for the optical beam 15. The thickness of the layer depends on the designed wavelength of the beam in cm and, as will be described in more detail with respect to Figure 20 below, needs to be 0.02 times the reciprocal of the absorption coefficient of the optical beam in the semiconductor layer. The light / electricity converter 1 can be encapsulated in a package that can have a front window which can be surface 7 or a separate window. This can also be coated to have an external surface adapted to function as an interface with air or an adhesive or glass around it. In a typical configuration, the light / electricity converter 1 can typically be a junction of semiconductor layers with conductors deposited thereon. In many embodiments, surface 7 is coated on one of these semiconductor layers or becomes one of the external surfaces.

[0180] The signaling detector 8 indicates that beam 15 is impinging on the photovoltaic cell 1 and transmits that information to the controller 13. In many cases, it also transmits received power, received optical power, identification information, the temperature of the receiver, and the photovoltaic power, as well as other data such as information relayed from a client device that can be control information. In this example, the system controller 13 is located in the transmitter 21 but can be located remotely therefrom. The control signal is via link 2

[0181] The signaling detector 8 indicates that beam 15 is impinging on the photovoltaic cell 1 and transmits that information to the controller 13, and in many cases also transmits received power, received optical power, identification information, the temperature of the receiver, and the photovoltaic power, as well as other data such as information relayed from a client device that can be control information. In this example, the system controller 13 is located in the transmitter 21 but can be located remotely therefrom. The control signal is via link 2 ​​​​​3 to a detector 24 in the transmitter.

[0182] The safety system 31 receives information from various sources, which are detailed below in FIG. In particular, from a small portion of the combined beam 15 from the beam combiner 32 and from the signal The information is transmitted from the power detector 8, typically via a data channel between the power receiver and the power transmitter. The safety system 31 outputs a safety indication to the control unit 13.

[0183] The power converter 1 has a bandgap E8 and typically has a voltage of 0.35 to 1.1 V. However, the use of multi-junction photovoltaic cells leads to even higher voltages. flows from the photovoltaic cell 1 through the conductors 2a and 2b having low resistance to the inductor 3. The inductor 3 stores a portion of the energy flowing through it in the magnetic field.

[0184] The automatic switch 4 is typically a MOSFET connected to a control circuit (not shown in FIG. 19). A transistor that switches between alternating states so that the current flows through it during the first part of the time. is allowed to flow through inductor 3 to ground during a second portion of the time. The inductor emits its stored magnetic energy as a current with a higher voltage than the photovoltaic cell. The current passes through diode 5, after which the power is available. The load can flow to 6.

[0185] The automatic switch 4 can be fixed frequency or controlled from the transmitter or client load. and based on the current, voltage or temperature at the load, or based on the current, voltage or temperature at the automatic switch be based on temperature, or on the current, voltage or temperature radiated by the photo / electricity converter 1, or may be based on some other indicator regarding the state of the system.

[0186] As shown in FIG. 16, the receiver can be directly connected to the load 6. Or the load 6 is external to the receiver, or is another device such as a cell phone or other power-consuming device, and can be connected using a socket such as USB / micro USB / Lightning (registered trademark) / USB Type C. The receiver typically further includes a load ballast used to dissipate excess energy from the receiver. This is not required by some clients. In most cases, there is also an energy storage device such as a capacitor or battery connected in parallel with the load 6, or the load 6 may include an energy storage device such as a capacitor or battery.

[0187] The transmitter 21 generates the beam 15 and directs it towards the receiver 22. In the first operating mode, the transmitter 21 searches for the presence of the receiver 22. This is done using a scan beam, or by detecting the receiver using a communication means such as RF, light, IR light, UV light or sound, or by using a camera to detect a visual indicator of the receiver such as a retroreflector or retroreflective structure, barcode, high-contrast pattern

[0188] or other visual indicator. Once a rough position is found, the beam 15 typically scans the proximity area around the receiver 22 at low power. During such a scan, the beam 15 is a photovoltaic or is detected by detecting the receiver using a communication means such as RF, light, IR light, UV light or sound, or by using a camera to detect a visual indicator of the receiver such as a retroreflector or retroreflective structure, barcode, high-contrast pattern or other visual indicator. Once a rough position is found, the beam 15 typically scans the proximity area around the receiver 22 at low power. During such a scan, the beam 15 is a photovoltaic or other visual indicator. Once a rough position is found, the beam 15 typically scans the proximity area around the receiver 22 at low power. During such a scan, the beam 15 is a photovoltaic or other visual indicator. Once a rough position is found, the beam 15 typically scans the proximity area around the receiver 22 at low power. During such a scan, the beam 15 is a photovoltaic or other visual indicator. Once a rough position is found, the beam 15 typically scans the proximity area around the receiver 22 at low power. During such a scan, the beam 15 is a photovoltaic It is necessary to collide with the photocell 1. When the beam 15 collides with the photocell 1, the detector 8 detects it and sends a signal to the controller 13 accordingly.

[0189] The controller 13 instructs the laser driver 12 to change the power P to the input to the gain medium 11 and / or instructs the mirror 14 to change either its scan speed or direction, direct the beam towards or hold at that position, and change the scan step speed in response to such a signal, either or both of these. When the gain medium 11 receives a different power P from the laser power supply 12, its small-signal gain, i.e., the gain received when a single photon crosses the gain medium and there are no other photons crossing the gain medium simultaneously, changes. When photons directed in the direction between the rear mirror 10 and the output coupler 9 pass through the gain medium 11, more photons are radiated in the same direction as the direction of the beam 15, and optical resonance occurs between the rear mi rror 10 and the output coupler 9.

[0190] The output coupler 9 operates at least in part in the spectral range between the first overtone of the C-H absorption at 6940 cm -1 and the second overtone of the C-H absorption at 8130 cm and typically consists of alternating layers of different refractive index materials, typically -1 deposited as a multilayer dielectric or semiconductor film on a substrate that becomes the surface of the gain medium 11, typically glass, plastic, or alternatively, Fresnel reflection can be used if the gain medium can provide a sufficiently small signal gain or has a sufficiently high refractive index. Standard metal mirrors can also be used. If the gain medium is a semiconductor or fiber amplifier, bra ​​A dog reflector can also be used. The output coupler 9 also transmits one part of the light and extracts the other part of the light from the wave traveling forward inside the resonator. Typically a third part is also extracted from the wave propagating backward inside the resonator and can consist of a highly reflective mirror combined with a beam extractor such as a semitransparent optical component .

[0191] The rear reflector 10 should be a highly reflective mirror, but a small amount of light is allowed to leak backward from it and can be used for monitoring or other purposes. These optical features need to operate at least in a portion of the spectrum between the first overtone of the C-H absorption at 6940 cm and the second overtone of the C-H absorption at 8130 cm -1 . -1 -HIt typically needs to operate in at least a portion of the spectrum between the first overtone of the C-H absorption at 6940 cm and the second overtone of the C-H absorption at 8130 cm . It can typically be constructed from alternating layers of materials with different refractive indices deposited on a substrate, which is usually glass, metal, or plastic. Alternatively, if the gain medium can provide a sufficiently small signal gain, Fresnel reflection can also be used. Standard metal mirrors can also be used. If the gain medium is a semiconductor or fiber amplifier, a Bragg reflector can also be used.

[0192] The gain medium 11 amplifies the radiation between the first overtone of the C-H absorption at 6940 cm -1 and the second overtone of the C-H absorption at 8130 cm -1 . However, it does not necessarily cover the entire spectral range. This is possible when sending a small signal gain larger than the loss caused by the output coupler 9 when excited with power P by the laser driver 12 . Its area, field of view, and damage threshold are at least 8 kW / m ​​​​2 / Stelladian / (1 -R) beam needs to be made large enough to maintain the beam. Here, R is the reflectivity of the output coupler 9 . This can be composed of a semiconductor material having a bandgap of 0.8 - 1.1 eV in a transparent host material doped with Nd ions, or other structures that can simulate radiation in this spectral range. The gain medium 11 is positioned in the optical line of sight from the rear reflector 10 to the output coupler 9, and thus, resonance of the radiation reflected by the rear reflector 10 between the rear reflector 10 and the output coupler 9 through the gain medium 11 is allowed .

[0193] For a typical implementation where the gain medium 11 is a semiconductor having a bandgap of 0.8 - 1.1 eV, it is preferably attached to a heat extraction device and can be excited electrically or optically by a laser driver 12 .

[0194] In a typical implementation where the gain medium 11 is a transparent host such as YAG, YVO4, GGG, or glass or ceramics doped with Nd ions, in this case, the gain medium 11 preferably optically communicates with a filter to extract radiation around 9400 cm from the radiation resonating between the rear mirror 10 and the output coupler 9 -1 .

[0195] The beam steering device 14 is shown to be controlled by a controller 13. This can deflect the beam 15 in multiple directions. Its area must be made large enough so that substantially most of the beam 15 is included even when tilted to the maximum operating tilt angle . Taking a simple 2D example. If the beam 15 is a collimated 5 mm diameter (1 / e ​2 a Gaussian beam of (diameter), and when the beam steering device is a single round gimbal mirror centered on the beam center, and when the maximum tilt required for the mirror is 30 degrees and assuming that the beam steering device 14 has no other openings, if the mirror has a 5 mm diameter similar to the beam, it will have an approximate 13% loss at normal incidence of the beam, while having an approximate 60% loss at a 60-degree tilt angle. This severely impairs the performance of the system. This power loss is illustrated in the graph of FIG. 17 as well as in FIGS. 2 2 and 23 below. 2 and 23 below.

[0196] At the start of operation, the controller 13 commands the laser driver 12 and the mirror 14 to perform a search operation. This is done by the laser driver 12 operating in the first state, directing the beam 15 in a general direction where the receiver 22 is likely to be found. For example, if the transmitter is attached to a corner of the ceiling of a room, the scan is performed downward and between two adjacent walls of the room. When the beam 15 hits the receiver 22 including the optical / electricity converter 1, the detector 8 sends a signal to the controller 13 for example. As long as such a signal is not received, the controller 13 commands the beam steering unit 14 to direct the beam 15 in other directions to search for the receiver. When such a signal is received from the detector 8, the controller 13 can command the beam steering unit 14 to stop or decelerate the scan and lock onto the receiver. The controller 13 then waits for the safety system 31 to generate a signal indicating that it is operating safely, and once such a safety signal is received from the safety system 31 it can command the beam steering unit 14 to stop or decelerate the scan and lock onto the receiver. The controller 13 then waits for the safety system 31 to generate a signal indicating that it is operating safely, and once such a safety signal is received from the safety system 31 it can command the beam steering unit 14 to stop or decelerate the scan and lock onto the receiver. The controller 13 then waits for the safety system 31 to generate a signal indicating that it is operating safely, and once such a safety signal is received from the safety system 31 , the controller 13 instructs the laser driver 12 to increase its power emission. Alternatively, the controller 13 may know the location of the receiver 22 and determine its location at a later stage. This can be done even without the safety signal being present.

[0197] As the laser driver 12 increases its power emission, the small signal gain of the gain medium 11 increases. As a result, the beam 15 carries more power and power transmission begins. Upon detecting a power loss greater than this threshold, the safety system 31 takes control of the situation. The controller 31 can then report its status to the laser driver 12. Command the change by reducing power to maintain the required safety level. Such power loss thresholds may be predetermined or dynamically set, and are typically At a level that represents a significant portion of the maximum permissible exposure level, typically the system noise figure Such a condition occurs when the beam 15 is no longer correctly directed to the optical / electrical power converter 1. that the equipment is not working properly, that any object has entered the path of the beam, or that a malfunction has occurred. Other indications of safe operation, e.g. through a user interface or API, may be provided. An indication from the user regarding the security of the transmission that may be displayed by the second security system or a security indication from a second security system. If there is an indication of full operation, the controller will increase power to the laser to compensate for the power loss. The controller 13 can also command the beam steering assembly 14 to It is also possible to instruct the search operation to be performed again.

[0198] There are two distinct stages in the exploration behavior. First, the robot searches for visual patterns. Using a capable camera, seeking a retroreflector, seeking a high-contrast image, (LED or a response signal from a receiver such as blinking light from another light source), or seeking another display a rough search is performed, or the rough search may be performed by using the scanning feature of the beam steering unit 14 Thus, a list of potential positions where the receiver can be found can be generated. The second stage is a refined search. Here, the beam steering mi rror 14 directs the beam 15 to a small area until the detector 8 sends a signal that the beam 15 is colliding with the optoelectronic converter 1 Here, refer to FIG. 20, which is a schematic diagram of the optoelectronic converter labeled as element 1 in FIGS. 16 and 19

[0199] The beam 15 collides with the photovoltaic cell 106 thermally connected to the heat removal system 107 The beam 15 is absorbed by the absorption layer 108, causing current to flow through the conductor 111, and the current is usually collected by the bus The optical power absorbed by the absorption layer 108 is typically converted into electric power and heat. While the electric power is transferred through the conductor 111 and the lower electrode most of the thermal energy is removed through the cooling system 107 Since the conductor 111 creates a shadow on the absorption layer 108, its efficiency is reduced. Therefore, the conductor 111 should be made of a material with a specific electrical resistance of less than 3×10 ohm * meter such as a material with high conductivity. Such a conductor should have a thickness in meters, that is, at least (0.034 * Pρ) / (V -6 * χ) m thick as shown Here, P is the power absorbed by the photovoltaic section measured in watts 2 ​​​where ρ is the specific electrical resistance of the conductor. V is the voltage output at the maximum power point by the photovoltaic cell, and χ is the ratio of the area of the absorption layer covered by the conductor. The absorption layer also needs to be thick enough to absorb most of the impinging beam 15.

[0200] To do this, the thickness of the absorption layer 108 measured in meters should be at least 0 .02 / μ .02 / μ 10 where μ 10 is the decimal attenuation coefficient measured in units of 1 / m.

[0201] Now, refer to FIG. 21 showing the block diagram of the safety system 31 in FIG. 19. The safety system 31 receives inputs from various sensors and subsystems and transmits the output to the controller 13 when the safety system is not an integrated part of the controller 13 or when the safety system is within an external control unit. The safety system 13 can also sometimes receive inputs from these various sensors and subsystems. Such inputs can be from a wavelength sensor 407 that primarily monitors the wavelength of the beam and provides information necessary to estimate the safety limit associated with the beam. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M The safety system 31 receives inputs from various sensors and subsystems and transmits the output to the controller 13 when the safety system is not an integrated part of the controller 13 or when the safety system is within an external control unit. The safety system 13 can also sometimes receive inputs from these various sensors and subsystems. Such inputs can be from a wavelength sensor 407 that primarily monitors the wavelength of the beam and provides information necessary to estimate the safety limit associated with the beam. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M 2 , symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M symmetry, polarity, power, divergence, coherence, and other information related to the beam and the above parameters. This can also receive information from a beam analyzer (401) that monitors beam characteristics such as shape, M Images from camera 404 that can be visual, thermal, IR or UV, or images from a power meter 406 that measures the power of the beam at various positions, can be received. In many cases a primary sensor connected to the safety system 31 may be used as an intrusion sensor (405) that monitors the beam for foreign objects crossing or approaching the beam path or its surroundings. This can also receive inputs from other sensors such as current, voltage, smoke, humidity and other environmental sensors. When these inputs are received, or at a pre-scheduled time, the safety system 31 evaluates the potential for a safety violation and issues a notification to the controller 13 if that evaluation exceeds a predetermined threshold.

[0202] Refer now to FIG. 22 showing a beam deflected by a mirror rotating about a single or multiple gimbal axes. The beam 15 impinges on a mirror 332 that rotates in two dimensions about two axes. The beam 15 forms a spot 333 on the mirror 332 and is deflected in different directions. The importance of selecting an appropriate center of rotation and mirror dimensions is made clear by referring to FIG. 23. In FIG. 23, when the mirror 332 is rotated here, the beam 15 is deflected here at a larger angle compared to FIG. 22. Due to the increased angle, the spot 333 here forms a projection on the mirror surface that is longer than the effective length of the mirror 332. As a result, a significant portion of the beam 15, labeled as 333A, spills over from around the mirror 332. This spillover reduces the brightness of the beam 15 by both reducing its power and cutting off the edges. This, in most cases, degrades the quality of the beam in the far-field. Typically, the beam diameter ​​​​​​​​​​​​​​ If it decreases in the near field close to the mirror or in the image of the near field, it increases in the far field. To achieve a system of minimum size that operates with relatively high efficiency, it is important to maintain the highest possible brightness. This can be achieved by reducing the brightness loss that the beam 15 undergoes over all angles within the system's field of view. This can be done by mounting the mirror such that the rotation center of the mirror is substantially close to the center of the beam, as measured by any of the weighted average of the beam intensity, the cross-sectional diameter of the beam at a constant intensity, or the center of the elliptical aperture through which the beam passes. Note that, in contrast to the projection of the length, the width of the beam projection on the mirror does not change depending on the collision angle. Increasing. To achieve a system of minimum size that operates with relatively high efficiency, it is important to maintain the highest possible brightness. This can be achieved by reducing the brightness loss that the beam 15 undergoes over all angles within the system's field of view. This can be done by mounting the mirror such that the rotation center of the mirror is substantially close to the center of the beam, as measured by any of the weighted average of the beam intensity, the cross-sectional diameter of the beam at a constant intensity, or the center of the elliptical aperture through which the beam passes. Note that, in contrast to the projection of the length, the width of the beam projection on the mirror does not change depending on the collision angle. This can be done by mounting the mirror such that the rotation center of the mirror is substantially close to the center of the beam, as measured by any of the weighted average of the beam intensity, the cross-sectional diameter of the beam at a constant intensity, or the center of the elliptical aperture through which the beam passes. Note that, in contrast to the projection of the length, the width of the beam projection on the mirror does not change depending on the collision angle. This can be achieved by reducing the brightness loss that the beam 15 undergoes over all angles within the system's field of view.

[0203] Figure 24 shows a schematic representation of the intensity characteristics of a typical beam. Contour 1 labels the 90% line of the maximum intensity, contour 2 labels the 80% of the maximum intensity line, contour 3 labels the FWHM (Full Width at Half Maximum) intensity line, contour 4 labels the 1 / e intensity line, contour 5 labels the 1 / e intensity line, and contour 6 labels the 1 / e 2 intensity line. Point 231 is approximately at the weighted average point of the beam, point 232 is at the center of the first contour, point 233 is at the center of the sixth contour, and all of these are effective points for setting the rotation center of the mirror. However, 4 to place the rotation center beyond such points, a large mirror is required to maintain the high radiance efficiency of the gimbal mirror. of the beam, point 232 is at the center of the first contour, point 233 is at the center of the sixth contour, and all of these are effective points for setting the rotation center of the mirror. However, to place the rotation center beyond such points, a large mirror is required to maintain the high radiance efficiency of the gimbal mirror. However, to place the rotation center beyond such points, a large mirror is required to maintain the high radiance efficiency of the gimbal mirror. However, to place the rotation center beyond such points, a large mirror is required to maintain the high radiance efficiency of the gimbal mirror.

[0204] It is also important to maintain high radiance efficiency with respect to other components. However, gimbal mirrors and the first lens that follow the laser typically have limited It is a fixed component.

[0205] Figure 25 shows a schematic side view of a laser diode from a direction orthogonal to the fast axis of the laser, and further shows a normal lens 242 for operation that substantially collimates the fast axis. In most cases, lens 242 is a compound lens including several optical elements. The laser 241 is connected to the heat sink 243 and emits the beam 15 to the interface layer 244. The interface layer 244 has a refractive index n with respect to the wavelength associated with the beam 15. The value of n is 1.000293 for an air interface at 532 nm and is even higher for oil or optical cement. The beam 15 has divergence in at least one direction. The FWHM profile of the beam 15 at the front surface of the lens 242 has a diameter d defined as the maximum distance between any two points on the FWHM profile. To have a high radiance efficiency, the lens 2 42 should have a numerical aperture NA of at least

Number

[0206] If a lens with a small numerical aperture is used, the radiance of the beam is reduced by the lens, resulting in poor efficiency of the system or a large receiver. These are the results in many situations. This can be disadvantageous. Using a small NA also causes heating of the lens holder. This causes two harmful effects. First, the lens moves from its optimal position due to thermal expansion, and second, a force is applied to the lens causing distortion in the lens, reducing its optical quality and consequently reducing the radiance of the beam. Additionally, a small NA can also cause reflections towards the laser. This can interfere with the laser mode and further reduce the radiance of the original beam. This is further detrimental to the radiance of the emitted beam. Light emitted from the edge of the lens can interfere with the operation of other parts of the system, such as beam monitors, tracking servo or other optical elements in the system, or cause excessive heating that can

[0207] interfere with the operation of other parts of the system. Now, refer to FIG. 26 which shows a block diagram of the laser protector 251. As described above, the safety system 31 evaluates the potential for a safety violation and notifies the controller 13 if such potential exceeds a threshold. The controller 13 then instructs the laser driver 12 to stop or reduce the power supplied to the laser 252 that can become a laser emitting beam 15 or a laser that can pump the gain medium used to generate beam 15. Stopping the power in this way must be ultra-fast. If the supplied power is To prevent such damage, a laser protector 251 is connected between the laser driver 12 and the laser 25 2, typically near the laser 252. The laser protector 251 typically comprises a diode, or an equivalent circuit / component, such as a Zener diode, varistor, or a circuit designed to rapidly drain such excessive negative voltage between current conductors, and is connected subsequently to protect the laser 252 from negative voltage. As a result, even if a negative voltage exists between conductors, current flows through the protection diode or equivalent circuit, causing a rapid decay of the voltage to a safe level. The laser protector 251 can also be used to protect the laser from overheating or from current surges by attenuating the power sent to the laser 252 when over-temperature or over-current is detected. As will be recognized by those skilled in the art, the present invention is not limited to what has been particularly shown and described above. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described above, as well as these variations and modifications which would be recalled by those skilled in the art upon reading the foregoing description and which do not exist in the prior art.

[0208] ​

Claims

1. 1. A system for optical wireless power transmission to at least one power receiving device, comprising: an optical resonator having a plurality of end reflectors and adapted to emit a light beam; 8,300 cm －１ From 12,500 cm －１ At least one having a wave number in the range The device is doped with neodymium ions in optical communication with a filter that attenuates radiation at frequencies a gain medium comprising either (i) a semiconductor device or (ii) a solid-state host, a first band gap energy located within the optical cavity and having a cooling A gain medium that is thermally attached to the system and configured to amplify light passing through it. and, A power supply configured to supply power to the gain medium to enable control of the small signal gain of the gain medium. A driver to a beam steering device configured to direct the light beam in at least one of a plurality of directions; 、 A power receiving device is disposed within the at least one power receiving device to transmit the light beam to a power receiving device having a voltage a light-to-electrical converter configured to convert a second band gap energy an optical / electrical power converter having configured to provide a signal indicative of the light beam impinging on the light-to-power converter. A detector; adapted to control at least one of the beam steering device and the driver's status. a controller integrated with the detector, the controller receiving a control input signal from at least the detector; Including, The light beam has a power of at least 8 kW / m ２ / steradian radiance, The overall radiance efficiency of the transmission between the transmitter and the at least one power receiving device is At least 20% of the system.

2. The overall radiance efficiency of the transmission between the transmitter and the at least one power receiving device is The system of claim 1 , wherein the ratio is at least 30%.

3. 3. The optical / electrical power converter according to claim 1, further comprising a voltage converter connected to an output of the optical / electrical power converter.

2. The system according to claim 1 .

4. 4. The method of claim 3, wherein the voltage converter is configured to track a maximum power point of the light-to-electrical power converter.

3. The system described in claim 3.

5. The system of claim 3 , wherein the voltage converter is a DC / DC boost voltage converter.

6. 6. The resonator according to claim 1, wherein the resonator includes at least one dielectric mirror. system.

7. 7. The system of claim 1, wherein the light-to-electrical power converter is a photovoltaic cell. 。

8. The system of claim 7 , wherein the photovoltaic cell comprises a III-V semiconductor material.

9. Claims further comprising an energy storage device, which may be a capacitor or a rechargeable battery.

9. A system according to any one of 1 to 8.

10. The system of claim 1 , further comprising an inductor.

11. The inductor is [0010] and [0025] and an inductance between where f is the switching frequency measured in Hertz and E ｇａｉｎ Joule is the band gap energy of the gain medium measured in units of V ｏｕｔｐｕｔ Is Boll is the output voltage of the DC / DC converter in units of P ｌａｓｅｒ ｄｒｉｖｅｒ The above the power measured in watts delivered to said gain medium by a laser driver. The system of claim 10.

12. The system is configured to receive information from the power receiving device.

12. A system according to any one of claims 11 to 11.

13. The information includes battery status, device identification, power required, voltage required, and a few key The system of claim 12 , comprising at least one

14. 14. Any of claims 1 to 13, further comprising a sensor for determining a temperature of the light to power converter. The system described in

15. and configured to modify the power of the light beam in response to changes in the temperature of the light-to-power converter. The system of claim 14 .

16. The system of claim 14 , wherein the temperature sensor output is received by the controller.

17. an optical window positioned between the photovoltaic light-to-electrical power converter and the beam steering device; 17. The system of claim 1, further comprising:

18. 20. The system of claim 17, wherein the window has a refractive index of at least 1.

5.

19. The window has a refractive index of at least 1.6 and is coated with an anti-reflective coating. Item 18. The system described in item 17.

20. the second band gap energy is less than the first band gap energy, 20. The system according to any one of items 1 to 19.

21. The controller is configured to cause the beam steering device to steer the light beam to the at least one power receiving device.

21. The system of claim 1 , adapted to direct

22. 1. A system for optical wireless power transmission to at least one power receiving device, comprising: an optical resonator having a plurality of end reflectors and adapted to emit a light beam; 8,300 cm －１ From 12,500 cm －１ At least one having a wave number in the range The device is doped with neodymium ions in optical communication with a filter that attenuates radiation at frequencies A gain medium comprising either a semiconductor device or a solid-state host, a first band gap energy located at said first band gap energy portion and thermally connected to said cooling system; a gain medium attached to the optical fiber and configured to amplify light passing therethrough; A power supply configured to supply power to the gain medium to enable control of the small signal gain of the gain medium. A driver to a beam steering device configured to direct the light beam in at least one of a plurality of directions; 、 A power receiving device is disposed within the at least one power receiving device to transmit the light beam to a power receiving device having a voltage a light-to-electrical converter configured to convert a second band gap energy an optical / electrical power converter having configured to provide a signal indicative of the light beam impinging on the light-to-power converter. A detector; adapted to control at least one of the beam steering device and the driver's status. a controller integrated with the detector, the controller receiving a control input signal from at least the detector; Including, The controller includes: causing the driver to vary a small signal gain of the gain medium; modifying the radiance of the light beam; Varying the power supplied by the driver; and Varying a scan speed of the beam steering device; and Varying the attitude of the beam steering device; and recording the scan pose defining a location of the light-to-power converter; By outputting a command that brings about at least one of the following, the stability caused in the system is A system configured to respond to an indication of all risks.

23. The indication of a safety risk posed in the system includes at least / from said detector configured to provide a signal indicative of a collision to a power converter; and At the resonator, the beam reflected from the at least one power receiving device is received.

23. The system of claim 22, wherein the level is obtained from a signal generated by a selected level.

24. 24. The optical / electrical power converter according to claim 22, further comprising a voltage converter connected to an output of the optical / electrical power converter.

2. The system according to claim 1 ,

25. 4. The method of claim 3, wherein the voltage converter is configured to track a maximum power point of the light-to-electrical power converter.

25. The system described in 24.

26. 25. The system of claim 24, wherein the voltage converter is a DC / DC boost voltage converter.

27. 27. The cavity according to claim 22, wherein the cavity includes at least one dielectric mirror. The system is as follows:

28. 28. The system of claim 22, wherein the light-to-electrical power converter is a photovoltaic cell. Tem.

29. 30. The system of claim 28, wherein the photovoltaic cell comprises a III-V semiconductor material.

30. Claims further comprising an energy storage device, which may be a capacitor or a rechargeable battery.

30. The system according to any one of claims 22 to 29.

31. 31. The system of any of claims 22 to 30, further comprising an inductor.

32. The inductor [0030] and [0045] and an inductance between where f is the switching frequency measured in Hertz and E ｇａｉｎ Joule is the band gap energy of the gain medium measured in units of V ｏｕｔｐｕｔ Is Boll is the output voltage of the DC / DC converter in units of P ｌａｓｅｒ ｄｒｉｖｅｒ The above the power measured in watts delivered to said gain medium by a laser driver. The system of claim 31.

33. The system is configured to receive information from the at least one power receiving device.

33. The system of any of claims 22 to 32.

34. The information includes battery status, device identification, power required, voltage required, and a few key 34. The system of claim 33, comprising at least one

35. 35. Any of claims 22 to 34, further comprising a sensor for determining a temperature of the light to power converter. The system according to any one of claims 1 to 5,

36. modifying the power of the light beam in response to changes in the temperature of the light-to-power converter.

36. The system of claim 35,

37. 37. The system of claim 36, wherein the temperature sensor output is received by the controller.

38. Further, an optical window is positioned between the photovoltaic light-to-electrical power converter and the beam steering device.

28. The system according to any one of claims 22 to 27, further comprising:

39. 40. The system of claim 38, wherein the window has a refractive index of at least 1.

5.

40. The window has a refractive index of at least 1.6 and is coated with an anti-reflective coating. Item 39. The system described in item 38.

41. the second band gap energy is less than the first band gap energy, 41. The system according to any one of items 22 to 40.

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