Today’s screens use a plate patterned with pixels formed from red, green, and blue LEDs arranged end to end, which shine in different intensities to generate the full spectrum of colours.

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.

The new stacked pixels can generate the full range of colours and measure about 4 microns wide. The microscopic pixels, or 'micro-LEDs', can be packed to a density of 5,000 pixels per inch.

“This is the smallest micro-LED pixel, and the highest pixel...