Although mobile devices such as tablets and smartphones let us communicate, work and access information wirelessly, their batteries must still be charged by plugging them in to an outlet. But engineers at the University of Washington have for the first time developed a method to safely charge a smartphone wirelessly using a laser.
As the team reports in a paper published online in December in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable & Ubiquitous Technologies, a narrow, invisible beam from a laser emitter can deliver charge to a smartphone sitting across a room — and can potentially charge a smartphone as quickly as a standard USB cable. To accomplish this, the team mounted a thin power cell to the back of a smartphone, which charges the smartphone using power from the laser. In addition, the team custom-designed safety features — including a metal, flat-plate heatsink on the smartphone to dissipate excess heat from the laser, as well as a reflector-based mechanism to shut off the laser if a person tries to move in the charging beam’s path.
“Safety was our focus in designing this system,” said co-author Shyam Gollakota, an associate professor in the UW’s Paul G. Allen School of Computer Science & Engineering. “We have designed, constructed and tested this laser-based charging system with a rapid-response safety mechanism, which ensures that the laser emitter will terminate the charging beam before a person comes into the path of the laser.”
Gollakota and co-author Arka Majumdar, a UW assistant professor of physics and electrical engineering, led the team that designed this wireless charging system and its safety features.
“In addition to the safety mechanism that quickly terminates the charging beam, our platform includes a heatsink to dissipate excess heat generated by the charging beam,” said Majumdar, who is also a researcher in the UW Molecular Engineering & Sciences Institute. “These features give our wireless charging system the robust safety standards needed to apply it to a variety of commercial and home settings.”
The charging beam is generated by a laser emitter that the team configured to produce a focused beam in the near-infrared spectrum. The safety system that shuts off the charging beam centers on low-power, harmless laser “guard beams,” which are emitted by another laser source co-located with the charging laser-beam and physically “surround” the charging beam. Custom 3-D printed “retroreflectors” placed around the power cell on the smartphone reflect the guard beams back to photodiodes on the laser emitter. The guard beams deliver no charge to the phone themselves, but their reflection from the smartphone back to the emitter allows them to serve as a “sensor” for when a person will move in the path of the guard beam. The researchers designed the laser emitter to terminate the charging beam when any object — such as part of a person’s body — comes into contact with one of the guard beams. The blocking of the guard beams can be sensed quickly enough to detect the fastest motions of the human body, based on decades of physiological studies.
“The guard beams are able to act faster than our quickest motions because those beams are reflected back to the emitter at the speed of light,” said Gollakota. “As a result, when the guard beam is interrupted by the movement of a person, the emitter detects this within a fraction of a second and deploys a shutter to block the charging beam before the person can come in contact with it.”
The next generation of nano-scale optical devices are expected to operate with Gigahertz frequency, which could reduce the shutter’s response time to nanoseconds, added Majumdar.
The beam charges the smartphone via a power cell mounted on the back of the phone. A narrow beam can deliver a steady 2W of power to 15 square-inch area from a distance of up to 4.3 meters, or about 14 feet. But the emitter can be modified to expand the charging beam’s radius to an area of up to 100 square centimeters from a distance of 12 meters, or nearly 40 feet. This extension means that the emitter could be aimed at a wider charging surface, such as a counter or tabletop, and charge a smartphone placed anywhere on that surface.
The researchers programmed the smartphone to signal its location by emitting high-frequency acoustic “chirps.” These are inaudible to our ears, but sensitive enough for small microphones on the laser emitter to pick up.
“This acoustic localization system ensures that the emitter can detect when a user has set the smartphone on the charging surface, which can be an ordinary location like a table across the room,” said co-lead author Vikram Iyer, a UW doctoral student in electrical engineering.
When the emitter detects the smartphone on the desired charging surface, it switches on the laser to begin charging the battery.
“The beam delivers charge as quickly as plugging in your smartphone to a USB port,” said co-lead author Elyas Bayati, a UW doctoral student in electrical engineering. “But instead of plugging your phone in, you simply place it on a table.”
To ensure that the charging beam does not overheat the smartphone, the team also placed thin aluminum strips on the back of the smartphone around the power cell. These strips act as a heatsink, dissipating excess heat from the charging beam and allowing the laser to charge the smartphone for hours. They even harvested a small amount of this heat to help charge the smartphone — by mounting a nearly-flat thermoelectric generator above the heatsink strips.
The researchers believe that their robust safety and heat-dissipation features could enable wireless, laser-based charging of other devices, such as cameras, tablets and even desktop computers. If so, the pre-bedtime task of plugging in your smartphone, tablet or laptop may someday be replaced with a simpler ritual: placing it on a table.
The Latest on: Battery charging via laser
via Google News
The Latest on: Battery charging via laser
- realme narzo 30A with MediaTek Helio G85 SoC and 6000mAh battery launched in India at Rs 8,999on February 24, 2021 at 1:44 am
A is the new budget offering announced in India under the narzo series. The entrant in realme's narzo 30 series comes along with ...
- Realme Narzo 30 series launched: Mid-range 5G power, big battery for under $250on February 23, 2021 at 11:53 pm
Realme’s Narzo series stands out by offering capable silicon and big batteries, and this generally comes at a very affordable price. Now, the company has announced the Narzo 30 ...
- DEWALT® Reveals Its First 20V MAX* Line Laseron February 23, 2021 at 9:01 am
DEWALT® Lasers Powered by 12V MAX* and 20V MAX* Batteries For Versatility & Long RuntimeTOWSON, MD (February 23, 2021) – DEWALT® has unveiled its ...
- GAC Group's Breakthrough Fast-Charging Graphene Batteryon February 17, 2021 at 5:49 am
When it comes to electronic devices, there has been a lot of talk over the years about using graphene in batteries. This is primarily because it has high electrical conductivity, high charge carrier ...
- Samsung Galaxy F62 Unveiled With Massive 7000mAh Battery and Exynos 9825on February 15, 2021 at 2:08 pm
Samsung on Monday launched its new smartphone 'Galaxy F62' with flagship 7nm Exynos 9825 processor and a massive 7000mAh battery. Priced at Rs 23,999 for ...
- Finally! Samsung Galaxy F62 launched - packs MASSIVE battery | Check price, cashback, offers, featureson February 15, 2021 at 5:24 am
South Korean tech giant Samsung announced the launch of Galaxy F62 with flagship 7nm Exynos 9825 processor and a huge 7000mAh battery.
- Samsung Galaxy F62 With 7,000 mAh Battery Launched In India: Price, Features Explainedon February 15, 2021 at 5:16 am
Users can choose from Laser Blue ... up to 1TB via a microSD card slot. More importantly, the Samsung Galaxy F62 features a large 7,000 mAh battery paired with 25W fast charging support.
- Samsung Unveiled A Phone With 7,000mAh Battery You Probably Can't Buyon February 15, 2021 at 2:59 am
You can expand its storage via a microSD card up to ... along with One UI 3.1 skin. A 7,000mAh battery is included, and the device supports 25W fast charging. Wireless charging is not included.
- Electric Car Charging As Fast As Gasoline Is The Aim, But Barriers Remainon January 31, 2021 at 5:37 am
Recent news about faster battery charging ... Corbis via Getty Images) “It is difficult to mention one single company as there are over 50 which are working on fast charging technologies that ...
- How ultrafast charging batteries could help sell the transition to electric carson January 26, 2021 at 3:59 pm
“The bottleneck to extra-fast charging is no longer the battery,” claimed the firm’s chief executive. But is this fast-charging battery really a gamechanger? And if so: exactly how? Electric ...
via Bing News