CEA-Leti has demonstrated the technology for manufacturing Micro LED arrays for head up displays, and other mobile and wearable devices with built-in projectors including eye-wear.
The head-up and head-mounted displays is very suitable for pilots in planes as well as on-road vehicle-drivers where the displays allow pilots and drivers to receive key navigation data and information in their line of sight, so that they get less distracted while viewing the data. This technology also helps in projection devices such as smart glasses or nomadic projection devices with augmented reality provide directions, safety updates, advertisements and other information across the viewing field. LED microdisplays target above application markets due to low footprint, low power consumption, high-contrast ratio and ultra-high brightness.
CEA Leti researchers have fabricated gallium-nitride (GaN) and indium gallium-nitride (InGaN) micro LED arrays.
Market researchers are predicting faster growth for head-up displays. CEA Leti has shared a forecast published in MarketsandMarkets where the market for head-up displays alone to grow from $1.37 billion in 2012 to $8.36 billion in 2020.
“Currently available microdisplays for both head mounted and compact head-up applications suffer from fundamental technology limitations that prevent the design of very low-weight, compact and low-energy-use products,” said Ludovic Poupinet, head of Leti’s Optics and Photonics Department. “Leti’s technology breakthrough is the first demonstration of a high brightness, high-density micro-LED array that overcomes these limitations and is scalable to a standard microelectronic large-scale process. This technology provides a low-cost, leading-edge solution to companies that want to target the fast-growth markets for wearable vision systems.”
Key innovations by CEA Leti in fabricating such micro LEDs using integrated circuit manufacturing process include epitaxial growth of LED layers on sapphire or other substrates, micro-structuration of LED arrays (10μm pitches or smaller), and 3D heterogeneous integration of such LED arrays on CMOS active-matrices.
CEA Leti says "These innovations make it possible to produce a brightness of 1 million cd/m² for monochrome devices and 100 kcd/m² for full-color devices with a device size below one inch and 2.5 million pixels. This is a 100- to 1,000-times improvement compared to existing self-emissive microdisplays, with very good power efficiency. The technology also will allow fabrication of very compact products that significantly reduce system-integration constraints."
The high-density micro-LED array process was developed in collaboration with III-V Lab.