One of the first working full-color quantum-dot displays was shown off at a conference this week by a startup company that is working to commercialize the technology.

Quantum dots are nanoparticles made of inorganic materials that very efficiently emit a specific color of light (depending on the size of the dot) when they're excited either by a beam of light or by an electrical current. Quantum-dot displays promise low power consumption and rich, beautiful color, much like organic light-emitting diode displays (OLEDs). But QD Vision, the company that demonstrated the prototype display, believes they will also prove less expensive to make than OLEDs at the huge scales favored by display manufacturers.

This week, QD Vision demonstrated a four-inch quantum-dot light-emitting diode (QLED) display at the Society for Information Display's Display Week conference in Los Angeles. The company's cofounder and chief technology officer, Seth Coe-Sullivan, cautions that the display is an early prototype, but says it rivals the efficiency and quality of colors in an OLED display. He says there are some engineering hurdles that the company will have to clear before bringing the display to market, which will take three to five years. Reaction to the company's demonstration was positive but cautious.

The hope is that QLED will provide a sharper, more power-efficient alternative to today's dominant technology, liquid-crystal displays (LCDs), without being more expensive. The way LCDs work—by filtering light from a backlight to create colored subpixels—entails throwing out some light, thereby dimming the picture and wasting power. OLEDs, which use electrical current to excite materials that emit red, green, and blue light, have rich, bright colors and waste less power. But so far, OLEDs can't compete on price. This is because the display industry makes LCDs on huge glass panels, sometimes as big as a garage door, and then slices them up into whatever size is needed, for economies of scale. OLEDs can't be made at this scale—too much material gets wasted, and it's too expensive.

Companies that make OLED materials and manufacturing equipment, including Dupont and Kateeva, are working on methods for printing these devices at large scales with less waste, but Coe-Sullivan hopes printed QLED displays will leapfrog over OLEDs.