HDTV Magazine
Welcome, Anonymous  •  Sign In  •  Register  •  Help

I may have been wrong. Here’s some history.

Some years ago Qualcomm purchased an MIT display spinout called Iridigm and renamed the technology mirasol (with a small “m”). At a time before Apple created the consumer tablet revolution, the standard for non-PC media consumption was the eReader, and the standard for low-power reflective displays was (and still is) E Ink’s electrophoretic display technology.

But as good as E Ink was for reading black-and-white text, it had obvious limitations that encouraged several companies to develop competing technologies. The limitations were that, at the time, E Ink was limited to black and white and refresh time was too slow for video or even smooth animation. Iridigm had developed a remarkably elegant reflective technology that promised to overcome E Ink’s limitations, and Qualcomm invested huge amounts of money developing it.

The Iridigm technology used optical interference to create color, with the interference changes created by MEMS-actuated mirrors. As elegant as this approach was, it had practical shortcomings. The technology never developed well-saturated reds, and since color rendering was based on interference, color was very sensitive to viewing angle.

Still, when the competition was E Ink and the application was eReaders, mirasol color might have been good enough, and the

Timex Ironman ONE GPS+ with mirasol SMI reflective color display.  Timex is accepting pre-orders for the watch.  (Photo:  Timex)

Timex Ironman ONE GPS+ with mirasol SMI reflective color display. Timex is accepting pre-orders for the watch. (Photo: Timex)

Korean Kobo bookstore chain did produce a mirasol-based Kobo Reader for the Korean market. Not many units made it to the U.S. but I have one of them, and the color is unsaturated, varies with viewing angle, and has an iridescent quality (suggested in the original Iridigm name) that does not make reading or image viewing easier.

Nonetheless, other mirasol eReader projects were in the works when the consumer tablet revolution struck. Almost overnight, “good-enough” color wasn’t good enough, as the standard for color and motion was now that of the very well developed LCD. The other mirasol eReader projects vanished, and the other developmental color reflective technologies faded away to one degree or another. (LiquaVista, perhaps the most interesting of these, disappeared into the maw of Amazon. I have been assured that the LiquaVista program is alive and well, but beyond that NOBODY is saying ANYTHING.)

Qualcomm retreated into showing wristwatch prototypes, where mirasol’s deficiencies were less obvious and less objectionable, and they also purchased Pixtronix, which had developed a transflective in-plane MEMS technology with field-sequential LED-backlit color. I’ve gone on record as saying Pixtronix was much more likely to be successful than mirasol. (Sharp has combined the Pixtronix technology with its IGZO backplane and will soon be manufacturing these displays in commercial quantities, initially for industrial applications.)

Qualcomm, however, did not give up on mirasol. They developed a new generation of the technology called SMI. The original approach, called IMOD, could only implement one mirror position per subpixel, so a red subpixel was either red or black. SMI permits continuous mirror positioning, so each subpixel (now pixel) can render a full range of colors. In practice, color saturation is improved and the disturbing iridescent quality is reduced. Still, SMI would not be my choice for an eReader or tablet display.

But eReaders are not what Qualcomm is pushing. AT SID 2014, Qualcomm was showing a 5.1-inch smart-phone display with 2560×1440 pixels. (SMI allows much higher pixel density than IMOD with its area dithering, and Qualcomm was showing this off.) Not bad, but it’s hard to see how SMI will match the color quality of AMOLED and quantum-dot-enhanced LCD for smart phones.

More convincing were a 1.45-inch display with 353×352 pixels and a 1.6-inch with 384×384 pixels. Both displays were labeled “wearable” and both had the same 343 ppi pixel density.

Qualcomm was showing its own Toq smart watch, which incorporates the 1.45-inch display (I think), and which is available on Amazon for about $235. Qualcomm is not a manufacturer of consumer products, so we can assume the Toq is designed as a vehicle for mirasol development and exposure. Can this approach convince any “real” watchmakers? The answer is yes.

Timex has just announced its Ironman ONE GPS+ fitness-and-athletics-oriented smart watch, which contains a remarkable collection of hardware, in addition to its mirasol display, for an MSRP of $399.95 ($449.95 with a bundled hear-rate sensor.) Timex is taking pre-orders now.

The phone, which operates independently of a cell phone, includes GPS, text messaging, music storage/playback, interval times, distance and speed calculation, and your friends can use the GPS to track you in real time. The watch is compatible with Bluetooth heart-rate sensors.

The characteristics of mirasol SMI — sunlight readability, very low power consumption, and color (where full color and color fidelity are not required) — are well suited to this application.

Will Timex’s highly functional but expensive athlete’s watch be a winner that stimulates additional wearable uses for mirasol? If Timex has miscalculated, it may deter other potential mirasol customers, even if the display was not at fault. We shall see.

Was I wrong about mirasol? I might have been, but the jury is still coming in.

Ken Werner is Principal of Nutmeg Consultants, specializing in the display industry, manufacturing, technology, and applications, including mobile devices and television. He consults for attorneys, investment analysts, and display-related companies. You can reach him at kwerner@nutmegconsultants.com.


Posted by Ken Werner, August 18, 2014 2:22 PM

More from Ken Werner

» - Currently Reading

About Ken Werner

Kenneth I. Werner is the founder and Principal of Nutmeg Consultants, which specializes in the display industry, display technology, display manufacturing, and display applications. He serves as Marketing Consultant for Tannas Electronic Displays (Orange, California) and Senior Analyst for Insight Media. He is a founding co-editor of and regular contributor to Display Daily, and is a regular contributor to HDTVexpert.com and HDTV Magazine. He was the Editor of Information Display Magazine from 1987 to 2005.