Inorganic light emitting diodes (LEDs), composed of direct band gap materials, are the brightest, longest-lived light source, and demonstrate light, flexible and durable mechanical properties while maintaining ultra-low power requirements. However, integrating LED arrays with silicon-based circuitry to deliver voltage has remained challenging and expensive. This technology has developed a process to seamlessly integrate direct band gap substrates, such as compound semiconductor materials used in LEDs with silicon-based thin film circuitry. This technology has enabled the development of an active matrix addressed monolithic LED array. In addition, the utility may be expanded to areas of optical detection, microelectromechanical systems (MEMS), high-precision environmental sensors and piezoelectric systems.
This technology has solved the difficult task of integrating a silicon-based active matrix addressed display on temperature-sensitive LED wafers. While current projectors typically utilize a spatial light modulator (SLM) to produce shades from a light source that is always at maximum luminosity, this technology can turn off portions of the LED array light source, greatly reducing power consumption. This can improve the operating time of battery-powered portable devices such as cellphones and laptops, while offering unmatched contrast and response times compared to competing liquid crystal display (LCD) or digital light processing (DLP) technologies. The use of carbon nanotubes to form contacts between the substrates enables a small footprint and transparent optical properties for see-through displays and/or detection technologies.
The technology has been validated with a proof-of-concept fabrication of a monolithically integrated 10 x 10 LED passive matrix.
Tech Ventures Reference: IR M08-009, M10-012, M10-059