Sundiode, a Silicon Valley based company developing micro-LED technologies for display applications including AR and MR, has demonstrated a full-color micro-display, consisting of a stacked 3-color (RGB) micro-LED pixel array driven with an active-matrix Si CMOS backplane.

With the previously announced development of a stacked-RGB micro-LED pixel technology patented by Sundiode and developed in collaboration with KOPTI (Korea Photonics Technology Institute), a micro-display using the stacked-RGB pixels was recently achieved using a full-color-capable Si CMOS backplane from Jasper Display Corporation.  The compact 15.4 mm ´ 8.6 mm display has an array of stacked-RGB micro-LED pixels on a single chip that was bonded directly onto a Si CMOS backplane in its entirety, thus completely avoiding conventional pick-and-place processes required for transferring discrete R, G, and B subpixels.

The development demonstrates full-color operation of a micro-display with significantly enhanced utilization of the small pixel area of a micro-display.  In this display, the pixels are 100 microns in size to result in a resolution of about 200 PPI.  The next phase of the development is currently underway to significantly increase the pixel density, in full color, to be suitable for the AR and MR applications.

A micro-display with a stacked-RGB pixel array, where each pixel is an RGB-emitting stacked micro-LED device (left).  The micro-display of the left showing a video of fireworks at night, demonstrating the full-color capability (right).  Note that the surrounding areas around the display appear dark due to the capturing camera’s exposure being turned down to avoid image saturation.

The fully functional display shows the operation of a stacked-RGB pixel array together with a Si CMOS backplane and, as such, is a crucial milestone in the development towards ultrahigh-resolution full-color micro-displays.  With the development of epitaxial and fabrication technologies enabling the stacked-RGB pixel device, this breakthrough demonstration is an important step on the way to manufacturing of micro-displays based on micro-LEDs that are suitable for AR, MR, and Metaverse.

Jasper Display Corporation is a Santa Clara based fabless IC design company that leads the CMOS backplanes technology supporting micro-LED development. Jasper Display offers FHD and 4K resolution backplanes, with excellent current uniformity and flexible addressing. By working with Sundiode to showcase its 100-micron stacked-RGB micro-LED in a single-panel full-color display, Jasper Display demonstrated that its CMOS backplane technology for micro-LED can be customized to support customers’ needs ranging from low-power AR all the way up to automotive headlights, all with custom resolutions.

Sundiode plans continued development efforts towards the ultrahigh-resolution micro-displays using the stacked-RGB pixel technology.