29 June 2023
Mojo Vision powers highest-density red micro-LED micro-display
Mojo Vision Inc of Saratoga, CA, USA — which is developing and commercializing micro-LED display technology for consumer, enterprise and government applications — claims that it has made an important step in overcoming challenges of delivering high-performance and reliable full-color micro-LED displays by powering the world’s highest-density (14K ppi) red micro-LED micro-display.
Mojo Vision used its proprietary quantum dot (QD) process to display visually vibrant red micro-LEDs measuring 1.37μm in diameter and set on a 1.87μm pitch. The visual quality and efficiency at this size are critical in meeting the full-color requirements for augmented reality (AR) and extended reality (XR) markets.
A primary challenge with existing display technologies, such as organic light-emitting diodes (OLED), in today’s AR/VR headsets is the ability to deliver optimal brightness and contrast dynamically as environmental light conditions change. When micro-LEDs are commercially available, the displays will be able to provide rich device functionality in all ambient conditions for AR and XR emerging products. Mojo Vision’s high-density red micro-LED is claimed to be the industry’s first to overcome wavelength and visual challenges with ultra-high pixel density, brightness, contrast, color gamut and energy efficiency.
“The ability to make very small red, green and blue micro-LEDs on the same substrate is critical to achieving vibrant and effective full-color micro-displays,” says CEO Dr Nikhil Balram. “Powering a true red display, rather than leaning toward orange as others do, at this size and specification puts us a big step closer to producing a micro-LED display that will meet or exceed the current performance and form-factor requirements for AR and XR products.”
While it is typically easier to deliver high-quality micro-LEDs at larger sizes (>5μm), the industry has struggled with smaller micro-LEDs, particularly those using color conversion materials. Mojo Vision claims that its latest development sets a new benchmark for micro-LED manufacturers by achieving true red vibrancy at a record-small pitch, exceeding past records for red wavelengths of 620nm or more that are required by major color standards used in broadcast and consumer displays.
“Addressing all three comfort pillars — wearable, visual and social — in all-day-use smart glasses is critical for wide consumer adoption,” says Dr Bernard Kress, president of the International Society for Optics and Photonics (SPIE). “The display sub-system is at the core of this problem. Emissive display panels are preferred to traditional liquid crystal on silicon (LCOS) or digital light processing (DLP) panels that require larger volumes and higher drive power. Although micro-OLED panels can be effectively matched to bulky birdbath combiners, micro-LED panels are best suited for thin waveguide combiners due to their higher brightness,” he adds.
“Monolithic RGB micro-LED panels have been the industry’s holy grail for many years now but are still struggling to produce efficient pixels with pitches below 4μm, with challenges ranging from using InGaN instead of more mature AlInGaP, efficiency in red, reliability and thermal issues, and lack of 300mm wafer-scale fab,” Kress continues. “Mojo’s proprietary red and green QD conversion of mature blue GaN micro-LED panel technology at pixel pitches below 2μm can be a great alternative and provide effective solutions for today’s smart glasses.”
Mojo Vision says that its new prototype will support a more advanced display in lightweight glasses form factor. In May, the firm announced a partnership with DigiLens to advance display capabilities in AR/XR markets. The partnership closely followed Mojo Vision’s successful light-up of the first-ever 300mm blue GaN-on-silicon micro-LED array wafer.
“Full-color micro-LED micro-displays are going to start emerging in the market in the coming years,” notes Dr Guillaume Chansin, director of display research at Display Supply Chain Consultants (DSCC). “Mojo Vision’s prototype stands out as a new milestone, by demonstrating red color conversion with a sub-2μm pixel pitch,” he comments. “This development is significant for the micro-LED industry and shows the potential of Mojo Vision’s approach towards full-color, high-resolution micro-displays.”