Modulators come in three types: for red, green, and blue. Each pixel in a Mirasol display is actually made up of several modulators that display the three basic colors at different brightness levels. Switching these modulators on and off in the right combination offers full color at different brightness. In dark conditions, light is directed onto the panel’s modulators from LED lights at the edge of the panel.
A study by Pike Research published last year estimated that a 5.7-inch Mirasol display like the one seen by Technology Review would allow for at least twice as much Web browsing as an equivalent device with an LCD screen. Qualcomm plans to sell the displays to the same device makers—including HTC, LG, and Samsung—that already buy its mobile chips.
Chui says displays will be made to serve both full-size tablets and phones and that demonstration tablets and display components have already been provided to various partners.
However, Qualcomm is far behind its own previous public predictions of when the technology would appear in products. Technology Review and others were shown an e-reader last year, and were told that devices would be on shelves in 2011. Chui said that the Mirasol technology needed significant modifications before it would make economic sense to manufacture it.
The device seen by Technology Review was made in a pilot factory in Taiwan that has mostly produced sample displays distributed to potential partners and customers, although a relatively small number of commerical displays will be made there. Chui says that a second, larger factory in Taiwan, big enough for production at a very large scale, is under construction and will come online in mid-2012. With the larger factory incomplete, truly mass-market devices with Mirasol displays can only appear in the second half of next year. Qualcomm is planning to invest up to $975 million in the new factory.
Jennifer Colegrove, who follows new display technologies for the analyst company DisplaySearch, says that despite the delays to mass production, the Mirasol technology lacks much serious competition. “It’s really a very unique kind of display,” she says, citing its ability to match LCD for experience at much less power.
One possible rival is an electrowetting display technology being developed by Samsung. It uses voltage to move colored liquids. However, demonstration displays of the technology have so far been less polished than those shown by Qualcomm, says Colegrove.
Colegrove guesses that Mirasol’s debut in products has been hampered by the challenge of ensuring a near-perfect “yield” of the modulators that make up a display. Because millions are required to make each display, even a very low error rate would be problematic. “The LCD industry went through this same problem with yield, and it took years to solve,” says Colegrove.