One-dimensional LED array integrated polymer composite scanner for 2D imaging

A novel two-dimensional display that exploits the large deflection of composite-polymer (FR4) based mechanical actuator and high optical performance of inorganic LEDs is implemented. Structure of the display consists of a 1D semiconductor LED array integrated on a electromagnetically actuated platform. Refresh rate of the display is controlled by the resonant movement of the mechanical device, whereas the fast-scan is performed by the synchronous electronic modulation of the inorganic LED devices. Since composite polymer structural material is used as the mechanical structure, a proper refresh rate of 100 Hz is implemented by engineering the spring dimensions. Simultaneous motion of the slow-scan resonant movement along with the modulation of 1D LED array in perpendicular direction to the slow-scan axis enables the generation virtual pixels on a 20 image plane. Refresh rate is implemented at 99 Hz, giving a peak displacement of 2.45 mm at a drive power of 85 mW. Resolution of the display is 20 x 40 pixel on a physical size of 8 min x 2.25 mm. When considering only the LED array, the proposed display consumes 14% more power compared to a conventional dot-matrix LED display of the same performance. The advantages of using a significantly less amount of LED devices results in a more reliable operation, in terms of low probability of dead-pixel failure, easily controllable LED-to-LED variations. Robustness of the display is proven by insignificant variations of the performance (quality factor, resonance frequency and peak displacement) parameters for 3 million cycles. (C) 2011 Elsevier B.V. All rights reserved.