-
- News
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueThe Sustainability Issue
Sustainability is one of the most widely used terms in business today, especially for electronics and manufacturing but what does it mean to you? We explore the environmental, business, and economic impacts.
The Fabricator’s Guide to IPC APEX EXPO
This issue previews many of the important events taking place at this year's show and highlights some changes and opportunities. So, buckle up. We are counting down to IPC APEX EXPO 2024.
Getting to Know Your Designer
In this issue, we examine how fabs work with their design customers, educating them on the critical elements of fabrication needed to be successful, as well as the many tradeoffs involved. How well do you really know your customer? What makes for a closer, more synchronized working relationship?
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - pcb007 Magazine
Textured LED Gives Green light to Li-Fi
August 10, 2017 | A*STAREstimated reading time: 2 minutes
Standard light-emitting diodes (LEDs) used for home lighting can now transmit data more rapidly between electronic devices, thanks to new research from A*STAR.
Wireless visible light communication — also known as Li-Fi — relies on data signals encoded in incredibly brief pulses of light, far too quick for the eye to see. By supplementing congested Wi-Fi networks, Li-Fi could increase the capacity and speed of data transmission in offices, homes and public spaces. However, white LEDs typically use a phosphor coating to create a natural-looking white light, and the time it takes for the phosphor’s glow to fade away limits how quickly the LED can transmit data.
V-pits on the surface of an InGaN LED (left) scatter light into the device’s active layers, known as quantum wells (QWs – right). (© ACS)
Previous solutions typically required installing new types of white LEDs. Instead, Ee Jin Teo of the A*STAR Institute of Materials Research and Engineering, and colleagues, have developed a Li-Fi receiver that overcomes these problems. Rather than using a conventional silicon photodiode to detect transmissions, they found that an indium gallium nitride (InGaN) LED is an effective data receiver (ACS Photonics, "Textured V-pit green light emitting diode as a wavelength-selective photodetector for fast phosphor-based white light modulation").
Crucially, the team’s InGaN LEDs can detect only the ‘fast’ blue component of the phosphor’s white light, which fades in only one nanosecond, and not the ‘slow’ yellow component which takes more than 50 nanoseconds to fade away.
The researchers also gave their InGaN LED a textured surface, so that every square centimeter was covered with one billion V-shaped pits (see image), roughly 150 nanometers deep. These V-pits scatter incoming light, allowing the LED’s active layers to absorb more than twice as much blue light as an LED with a smooth surface.
Tests with a white LED showed that the InGaN LED with V-pits was a much better receiver than a standard silicon photodetector.
“Using a silicon photodetector, the white LED can reach a switching speed of five megahertz — this typically means a data transmission rate of up to 100 megabits per second,” says Teo. “With our InGaN LED as a detector, this switching speed can be increased by four times, enabling faster data transmission rates from white LEDs.”
She notes, however, that since the receiver is only picking up part of the white LED’s light, it may reduce the range over which data can be transmitted.
“The next stage of our research,” she adds, “is to implement this concept into a dongle where the same LED can be used for transmission as well as detection of data.”
Suggested Items
Indium Corporation to Present, Exhibit at EPP InnovationsFORUM
03/28/2024 | Indium CorporationIndium Corporation is set to present and exhibit at EPP InnovationsFORUM, one of Europe’s premier single-day electronics manufacturing forums, on April 17 in Leinfelden-Echterdingen, Germany. Topic areas for 2024 will include AI, automation, sustainability, and quality.
Indium Corporation, Industry Partners to Showcase Products “Live@APEX”
03/26/2024 | Indium CorporationIndium Corporation®, in cooperation with its industry partners, will feature its proven solder solutions live on the show floor throughout IPC APEX Expo from Apr. 9‒11 in Anaheim, Calif., U.S.
Indium Corporation Experts to Present Throughout IPC APEX EXPO
03/18/2024 | Indium CorporationIndium Corporation’s leading technical experts are set to deliver and participate in a number of presentations and panel discussions throughout IPC APEX Expo, April 9-11, in Anaheim, Calif., U.S. Topics will include sustainability, assembly processes, and EV electronics.
Indium Corporation Celebrates 90 Years of Materials Science Innovation
03/13/2024 | Indium CorporationIndium Corporation will commemorate its 90th anniversary on March 13. Indium Corporation’s innovative products, especially its advanced soldering solutions, are found in many common consumer electronics and high-reliability technologies such as electric vehicles, mobile devices, life-saving medical devices, and emerging 5G technology to name just a few.
Indium Corporation to Showcase Proven EV Products and High-Reliability Alloys at Productronica China
02/28/2024 | Indium CorporationAs a materials pioneer and trusted partner in electric vehicle (EV) and e-Mobility manufacturing, Indium Corporation is proud to showcase its high-reliability alloys and soldering solutions at Productronica China, March 20-22, in Shanghai.