An LED-based image sensor with energy harvesting and projection capabilities college of technology
The light emitting diode (LED) technology has experienced great improvements in efficiency and cost reduction since the first visible light LED was invented in 1962. At the same time, because LEDs exhibit excellent photovoltaic performance, their capabilities of sensing light and harvesting energy have also been explored and studied for many years. By triple functionality of LEDs, they are widely used in a variety of research areas including visible light communication, robotics, structured light application and so on. Meanwhile, this triple functionality of LEDs also inspired researchers to combine and implement different functions in one system. ^ In this thesis, An LED-based image sensor with energy harvesting, image sensing, and projection capabilities was designed. A proof-of-concept prototype was fabricated and tested. The experimental setups, measurements and data analysis were carried out on the sensor prototype. The results shows the LED-based image sensor was able to work in three different functions. When the sensor works in the image sensing mode, clear images can be captured and easily be distinguished from the background. When the sensor works in the projecting mode, a linear amplification of optical images by 1.5 X and optical density of 28.9 µW/cm2 were achieved on a white screen around 9 inches away from the prototype. In addition, the sensor can harvest 16.2 mW of power when all of LEDs are configured to harvest energy.^
Walter Daniel Leon-Salas, Purdue University.