OLED Versus LED – The Display Market Battle
Even though there had been research into OLED technologies since 1960, commercialization commenced with Pioneer’s car audio display units in 1997, and full colour 5.2 inch OLED display went into mass production the following year. Nowadays, the heated OLED market has received significant investment from manufacturers and is seen as the future of flat panel displays. With new applications of the technology appearing at major trade shows and exhibitions around the World, some explanation of the technology and its potential is in order.
Classification of OLED Products:
By organic fluorescent materials
By color displays
By passive/active matrix
Investment of Taiwanese manufacturer into OLED technologies
Ritek Corporation leads the way in OLED
As a leading manufacturer in CD-R with experience in small molecules and strong mass-production capabilities, Ritek Corp. will venture into the research and development of OLED and expects to mass-produce such products in April. The firm will set up a second full-colour OLED production line in October, and full production is slated for next year. The firm will mainly produce single-color and OLED during the initial period. As for full-color OLED, the firm will begin relevant R&D efforts with the year and introduce these latest products by 2001, however. Ritek, with its ambitions to be the No.1 manufacturer in OLED, plans to produce monochrome and multi-colour displays, and from July or August, will work with Motorola on the development of passive and active matrix technologies. Initially, these glass substrates will be used for TV game, mobile phone, PDA and automobile panels. Ritek also plans to spin-off its OLED department.
Wintek Corporation invests in Winled Corporation
Wintek has invested NTD 650 mil in subsidiary Winled Corporation, with mass production due second quarter this year. Its OLED technology is obtained from a major American manufacturer, and it has also built a new research and development centre in Michigan. Wintek's glass substrates will also be 400mm x 400mm. Wintek's total planned investment is NTD 400 mil, and its products will be used in vehicle displays and mobile phones. Apart from OLED, Wintek is also looking at PLED.
Delta Electronics and its subsidiary Delta Optoelectronics
The next manufacturer to enter this market after Cambridge Display Technologies (CDT) will likely be Delta Electronics, which is already working with CDT to develop new mass production and colour display technologies. Test production with 14 inch x 14 inch glass substrates is due in the second quarter this year, with up to 3,000 units of production per month. Depending on the development situation, this venture may build a second production line in 2001 with production capacity of up to 1-mil units per year. This cunning commercial move will position Delta as the first PLED maker in Taiwan and opens new opportunities for the video display industry.
Giga Storage works with Materials Research Laboratories
Giga Storage, which also has organic chemistry and large area thin-film splash plating technologies, is also rushing into the OLED market in cooperation with Materials Research Laboratories of the Industrial Technology Research Institute on production, development, materials, mass production and other technologies. Giga Storage plans for the mass production of monochrome OLED displays next year, and colour OLEDs in 2002. Giga Storage believes that, in the mobile phones market, OLED will replace the significant market for STN-LCD technologies given OLED's advantages in price and production costs. At the moment, OLED is slated for such as applications as vehicle displays, palm tops and PDAs, with future applications in such appliances as digital cameras and camcorders.
ProDisc Technology completes test production in the third quarter
ProDisc Technology has established a new division for opto-electronics and video displays, with its emphasis on OLED and back projection display screen. ProDisc believes that OLED is similar in its production technologies with CD-R, and, with more than two and a half years of research and development efforts and NTD 70 mil of equipment, two new production lines are due in August, with samples due out at the end of the year and full scale mass production sometime next year.
Problems facing OLED:
Materials
Even though OLED has stormed into the video display market, it is so far only in the market for small-sized displays and the technology is yet to mature. For now, replacing TFT-LCD is still a distant dream. Materials for OLED have yet to settle down to common standards. If each manufacturer develops its own materials this will evade the problem of patents and preserve competitiveness in price. However, while OLEDs used in small-sized displays can still preserve reasonable efficiency, but this plunges as display size increases.
Packaging
A major problem with life span is dirt and water vapour. Water vapour on ITO substrates, inside organic materials, inside vacuum deposited cavity body, on metal electrode, on organic layers, etc. will see to equipment's life span being significantly shortened even though the equipment was dry when it left the production line. So it is crucial issue to separate the components from water vapour to stop its quality degrading. For now there is no perfect way to package the layers: a common method is to use resistor hot wire heating, E-beam or splash plating to sink a protective layer on top of the OLED unit as a basic protection before UV hardened resin packaging.
As OLED uses organic materials, low temperature is required during assembly. While UV sealing polymers was initially used given that hardening speed must be extremely fast given that it will directly come into contact with the fluorescent materials. However, better resistance to temperature, humidity and other crucial factors will require new improvements. As for adhesiveness, UV polymers still pales in comparison to heat-hardening epoxy resin and apart from coating its use is still restricted.
For primary packing as the protective layer produces multiple layer inner stress, this must be carefully handled, especially for those materials that can have plasticity deforming and stress slackening. Also, OLED is even more susceptible to water vapour and oxgyen, and sealing polymers still require less water penetration and lower outgas, faster hardening, and better metal adhesiveness. These aren't just the only problems: full colour OLED still has its bottlenecks. LCD is maturing and while OLED has strong advantages to replace TN and STN-LCD, but replacing TFT-LCD would still be a distant dream unless product lifespan, luminousity and packing technologies are improved, and prices fall. Hence OLED can still not replace LCDs at this stage.
Reference: Industry Material 2000/4, Materials Research Laboratories of Industrial Technology Research Institute, Nikkei, Semiconductor Industry News
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