Do you own a smartphone? I do. And I charge it every day, in the evening. I even have a friend who charges his iPhone two or three times a day, but he’s an extreme talker. However, great efforts are being made by scientists at the University of Cambridge toward making batteries last longer by recovering the power lost through the phone’s inefficient OLED screen.
More specifically, Arokia Nathan and his colleagues at Cambridge observed that only about 36 percent of the light produced by OLED displays, which are now among the few most sophisticated displays on the market, is actually directed forward.
They put small photovoltaic cells on the screen’s back and sides to capture the light losses. The device captures both ambient and recycled light and contains a thin film transistor circuit to even out the voltage spikes produced by the PV cell so it doesn’t harm the battery.
The team used a supercapacitor for storing the produced energy, before it’s gathered enough to be put into the battery at a pace that it can bear.
Efficiency figures of 11 to 18 percent are being envisioned, which are pretty promising for a start, taking into consideration that rooftop solar panels get around that upper limit frequently. Nathan even plans to embed MEMS technology in this device and convert small mechanical shocks into electricity, as well.
If this invention could be used to take the strain off the battery, then maybe a smartphone’s could last for 4 or 5 days with intensive usage. The market for this device would nevertheless be a huge one, since it’s almost painful to remember to charge the phone each and every night.
Ambient light-scavenging devices had been conceived in the past, too. I remember Steve Jobs patented such a contraption a couple of years ago and wanted to use it in a screen that had a solar cell behind the actual screen.