Engineers invent vertical, full-color microscopic LEDs

Jennifer Chu | MIT News Office
February 1, 2023

Take apart your laptop screen, and at its heart you’ll find a plate patterned with pixels of red, green, and blue LEDs, arranged end to end like a meticulous Lite Brite display. When electrically powered, the LEDs together can produce every shade in the rainbow to generate full-color displays. Over the years, the size of individual pixels has shrunk, enabling many more of them to be packed into devices to produce sharper, higher-resolution digital displays.

But much like computer transistors, LEDs are reaching a limit to how small they can be while also performing effectively. This limit is especially noticeable in close-range displays such as augmented and virtual reality devices, where limited pixel density results in a “screen door effect” such that users perceive stripes in the space between pixels.

Now, MIT engineers have developed a new way to make sharper, defect-free displays. Instead of replacing red, green, and blue light-emitting diodes side by side in a horizontal patchwork, the team has invented a way to stack the diodes to create vertical, multicolored pixels.