By Brian Fuller For the New Tech Press Network
LOS ANGELES, CA – Small is big, at least in the eyes of MicroEmissive Displays Ltd. (MED on the AIM) a Scottish electronics company that’s betting polymer organic LEDs (P-OLEDs) attributes are about to crack open a huge market in tiny displays.
Based in Edinburgh, MED has married P-OLED IP from Cambridge Display Technology Ltd, with tried-and-true semiconductor manufacturing techniques, for a cost-effective 0.24-inch color polymer OLED television. The device leverages compact magnifying optics, to produce a large virtual image that can be used in a variety of portable consumer applications with a significant improvement in power consumption.
The market for microdisplays sold into personal viewers is growing at about 50% a year, according to Steve Marsland, Managing Director of McLaughlin Consulting Group (MCG) in Menlo Park, CA, which tracks the personal viewer marketplace. "From $22M in 2006, 2008 sales are forecast at between $40 - $60M, depending on the 2008 holiday season. And sales of microdisplays for personal viewers in 2010 are forecast at a minimum of $65M, but could reach nearly $200M if personal viewer makers can market the products effectively to consumers."
The market for personal viewers themselves is forecast to grow to nearly $1B in 2010, according to Marsland. but all bets are off if Apple comes out with the iGlasses product in the next two years. "They are the one company positioned with all the elements to create wide public acceptance for this product category."
MED recently delivered 60,000 of it's P-OLED displays Estar Displaytech Co. Ltd, for the production of personal display headsets. “We chose eyescreen™ ME3204 because its performance meets the current market requirement as well as provides low power consumption and small dimension, which are important to portable electronic devices," said Makoo Liu, general manager for Estar. "Those attributes and the technical support from MED and it's partner, Cytech Technology Ltd., were the deciding factors."
According to Jennifer Colgrove of iSuppli, that delivery represents more than 10 percent of the shipment projection for 2008. "Most of the shipments of microdisplays are LCDs, but OLED technology from companies like MED are making significant inroads on the market." Colgrove stated. "OLEDs are simple, lightweight and potentially less expensive in the types of applications MED targets." Colgrove predicts unit shipments to rise from 325,000 in 2007 to 1.3 million by 2012.
"OLED displays could replace LCDs in many applications,” agreed Ian Underwood, MED co-founder, and co-inventor of its P-OLED microdisplay technology.
The MED microdisplay, on exhibit at the SID Conference in Los Angeles May 18-23, comes at a time when enormous LCD displays are flooding homes as consumers rush to replace their bulky CRT-based televisions with sleek flat-panel displays. But at the same time, consumers are becoming savvier about their use of mobile electronics. Displays are built into virtually every mobile device today, but the viewing attributes and high power consumption are ongoing issues for designers and consumers alike.
MED’s P-OLED microdisplay, based on technology that emerged in the early 1990s from work done at the Cavendish Laboratory of Cambridge University, claims three major attributes: Vivid pictures, vastly lower power consumption than LCDs and a familiar simpler manufacturing process. Leveraging the economies of scale of semiconductor manufacturing, MED is building cost-efficient small devices for use in numerous portable applications, from head-mounted displays and video glasses to electronic viewfinders and other vision systems. Devices such as MP4 and personal video players will benefit as well.
“Electronically it’s a single-component solution,” Underwood said. “The customer is buying a single-chip solution and a single-piece optomechanical solution. So in terms of design-in it’s a whole lot simpler” than competing microdisplay technologies.
Other technologies have tried to go micro before, but often struggled with perceived picture quality. A key advantage of P-OLED technology is its high contrast ratio--that’s defined by how black is black. With back-light-driven LCDs, the black is never really black; instead it’s more like shades of grey because of the constant presence of the backlight. P-OLED technology however, doesn’t require a backlight, so the blacks are truer. “You have an inherently high-contrast display. Black in P-OLED is vividly black,” Underwood noted.
An additional consideration is the effect of ambient light. “The problem is that ambient light washes out the black,” Underwood said. The picture on a laptop, a television screen or a cell phone viewed in daylight conditions is affected by ambient light, whereas movie theaters are kept very dark to retain high contrast on the cinema screen. The advantage of a P-OLED microdisplay used in an electronic viewfinder or in video glasses, is that the module creates a little “dark room” around the microdisplay when it’s viewed near to the eye, blocking out ambient light and retaining the intrinsic high contrast of the P-OLED display.
But what could emerge as the strong suit for P-OLED technology is its enormous power saving advantages—especially as the world increasingly goes green. Often electronics-power advantages are, for consumers abstract. But those consumers who are rushing out to buy huge flat-panel displays are seeing the 6X increase in the display’s power consumption come roaring home in their utility bills. That’s making them more aware of the power of displays.
A backlit LCD screen in a camcorder or PDA might burn 300-400mW while a microdisplay LCD burns around 150mW. MED’s P-OLED microdisplay, however burns 50mW or less. That means ODMs can be assured of longer battery life or can design in smaller batteries, making the end product smaller and lighter and with less impact on landfills at end of life.
In a 2006 interview, Terry Nicklin, then a marketing director for Cambridge Display Technology (currently with service provider Qi3), put it a different way, when referring to the benefits of OLED television panels:
“With an LCD, the backlight is on all the time, as you know, so it’s always consuming 100 percent of its power. On average, pixels are only utilizing 15 percent of their full brightness. So in the case of an emissive technology, such as OLED, the pixels only have to work 15 percent as hard as they would if they had to be on full-white all the time. That gives us tremendous benefits.”
What has helped propel P-OLED technology for microdisplays is familiar manufacturing processes. The buzz recently has focused on leveraging ink-jet-printing technology to make such tiny displays; that’s a technology that’s still being vetted. MED uses spin-coat technology, which has been around as long as semiconductor manufacturing.
Using a 200-mm wafer, the company deposits a drop of polymer into the spin-coat process, which creates a continuous layer. “Within a pixel we have three dots that emit white light. Then above them a red, green and blue filter,” Underwood said.
The manufacturing process for MED’s eyescreen™ ME3204 product starts by taking a mirrored, fully processed CMOS wafer, acting as the active matrix backplane, and depositing on it a series of nano-scale layers. One of these layers consists of the light-emitting P-OLED material generating white light when a small electric current is passed vertically through it. The cathode is deposited as a thin, semi-transparent metallic layer. A protective inorganic/organic multilayer thin film encapsulation is deposited over the entire structure. The silicon wafer is then laminated to a glass wafer containing patterned color filters, which filter the white light to provide the red, green and blue sub-pixels that make up a color display.
Not only has the manufacturing process been wrung out over decades of semiconductor manufacturing, but it yields a simple cost-effective device.
“We have fewer components,” Underwood said. “If it’s LCD, you’ve got a polarizing optics, backlighting, mechanical components and we have none of it. The 'backlight' is the P-OLED; we don’t use polarized light.”
A couple of issues may dog the uptake of P-OLED technology however: lifetime and applications.
The rap against organic electronics of any size or shape has been their life expectancy is generally lower than other solutions, and the purity of color would fall off during the devices life. In flat-panel applications, OLEDs have been found to have a lifespan of 14,000 hours, about a quarter of what an LCD version might offer.
CDT’s Nicklin, in the 2006 interview, pointed out that scientists had just announced for the blue P-OLED material the equivalent to a lifetime of 200,000 hours from 100cd/m2. That, he said, was nearly 10 times the lifespan they’d achieved at CDT just two years prior.
“Lifetime, as a number in isolation, is not very meaningful,” Underwood said. “You have to look at the application.” At one extreme, an electronic viewfinder in a consumer grade video camera might experience only a few hundred hours of accumulated use during the intended lifetime of the video camera. On the other extreme, an airport information display might be required to operate 24/7 for 50,000 hours.
“What OLED companies are doing is targeting applications where the technology can meet the lifetime requirements of the products,” he said. “As time passes and the technology matures, more and more of those applications will come within reach of the technology.”
And there’s the rub: what applications will really benefit from MED’s technology? Will consumers be watching movies inside specially-made glasses or headsets? It’s certainly not outside the range of possibility in a world where it was once unthinkable that people would walk down the streets listening to music streaming into their ears.
For now, MED is refining its model, which uses CMOS-silicon wafers from UMC in Taiwan and runs them through its manufacturing plant in Dresden, Germany. The company gets its color-filter-on-glass wafers from Toppan and uses USI in China for dicing, packaging, and assembly and final test.
MED looks at Asia as its No. 1 market, followed by the United States and Europe. It claims no direct competitors based on P-OLED technology at the moment (it has a license from CDT to use their P-OLED technology in the manufacture of microdisplays).
Kopin (Westboro, Mass.) makes an LCD microdisplay, an AM-LCD technology for its CyberDisplay line.
DisplayTech (Longmont, Colo.) makes microdisplays using Ferroelectric Liquid Crystal (FLC). eMagin Corp. (Hopewell Junction, N.Y.) has the closest competitive technology, using small molecule OLED technology to produce an active matrix OLED-on-silicon display. eMagin is targeting different markets than MED. With its higher definition displays selling at much higher prices than those of MED, it is selling into specialist and niche areas such as headsets for computer gaming enthusiasts as well as the US military and homeland security markets.
Brian Fuller has been in the media business for almost 25 years. Formerly the editor in chief of EE Times he is currently driving new-media strategy and content for media-relations firm, Blanc & Otus in San Francisco.