Path: EDN Asia >> News Centre >> Consumer Electronics >> LEDs capture fingerprints and signatures
Consumer Electronics Share print

LEDs capture fingerprints and signatures

14 Aug 2013

Share this page with your friends

The researchers have pressed letters into the top of the device, which produces a corresponding light output from the bottom of the device. This output – which can all be read at the same time – can be processed and transmitted.

The ability to see all of the emitters simultaneously allows the device to provide a quick response. "The response time is fast, and you can read a million pixels in a microsecond," said Wang. "When the light emission is created, it can be detected immediately with the optical fibre."

The nanowires stop emitting light when the pressure is relieved. Switching from one mode to the other takes 90ms or less, Wang said.


Mechanical pressure LED sensor

Figure 2: Professor Zhong Lin Wang with the sensor device that converts mechanical pressure directly into light signals that can be captured and processed optically.


The researchers studied the stability and reproducibility of the sensor array by examining the light emitting intensity of the individual pixels under strain for 25 repetitive on-off cycles. They found that the output fluctuation was approximately five per cent, much smaller than the overall level of the signal. The robustness of more than 20,000 pixels was studied.

A spatial resolution of 2.7μm was recorded from the device samples tested so far. Wang believes the resolution could be improved by reducing the diameter of the nanowires, which allows more nanowires to be grown, and by using a high-temperature fabrication process.


 First Page Previous Page 1 • 2


Want to more of this to be delivered to you for FREE?

Subscribe to EDN Asia alerts and receive the latest design ideas and product news in your inbox.

Got to make sure you're not a robot. Please enter the code displayed on the right.

Time to activate your subscription - it's easy!

We have sent an activate request to your registerd e-email. Simply click on the link to activate your subscription.

We're doing this to protect your privacy and ensure you successfully receive your e-mail alerts.


Add New Comment
Visitor (To avoid code verification, simply login or register with us. It is fast and free!)
*Verify code:
Tech Impact

Regional Roundup
Control this smart glass with the blink of an eye
K-Glass 2 detects users' eye movements to point the cursor to recognise computer icons or objects in the Internet, and uses winks for commands. The researchers call this interface the "i-Mouse."

GlobalFoundries extends grants to Singapore students
ARM, Tencent Games team up to improve mobile gaming


News | Products | Design Features | Regional Roundup | Tech Impact