While PMOLED in the early days was the first generation technology for OLED production, AMOLED manufacturing technology, which is applied to smartphones, can be categorized as the second generation. In order for AMOLED to further expand its presence in the display market, the product range should reach beyond mobile display. This is because for the heart of the display market is television.
Recently, the focus of AMOLED development, led by Samsung SMD and LGD, has been shifted from small mobile display to TVs of 30 inches and larger. Although general consumers do not recognize the necessity of AMOLED TVs as of yet, display experts are increasingly putting emphasis on its significance.
The reason can be found in the emergence of the 3D TV market. Even LCD developers admit that AMOLED has superior 3D image quality when compared to TFT-LCD. Each manufacturer uses different technology for 3D image representation, but normally they use a refresh rate that ranges from 120 to 240 Hz for clearer resolution.
Today, 240Hz is adopted for more smoother and faster play for videos on LCD, however, LCD is based on the mechanism that controls the quantity of light using the movement of liquid crystal, higher speed means greater restriction to the movement; but fast running is an advantage for AMOLED which has response characteristics of a few ums. Indeed, the 240Hz 3D AMOLED that Samsung SMD submitted at FPD International, held in Japan November 2010, demonstrated the quality, which is unmatchable to that of LCD.
The problem is completing the development of production technology that will enable manufacturing large size AMOLED displays that are over 30 inches. What is required to build a 30- to 40-inch AMOLED TV, while maintaining the price competitiveness against LCD, is 8th generation production technology. So far, 5.5th generation technology for backplane and 5.5 generation of 4-split deposition equipment have been developed, and Samsung SMD has started installment of 5.5th generation production equipment since December 2010. At the moment, it may seem too premature to talk about 8th generation, but the investment in 8th generation equipment must be promptly made to prepare for the competition against LCD.
Institutions such as Ministry of Knowledge Economy, Ministry of Culture and Tourism and the Korea Communications Commission are gearing up to foster 3D content developers to lead the 3D market from 2015, when 3D broadcast will be officially launched. This trend is resonated in other parts of the world as well, including the U.S. and Japan, and, according to the industry estimation, 3D TV sales will likely reach 200 million units by 2015. 3D AMOLED production, therefore, should begin no later than in 2013, in order to secure a comfortable niche in the TV market; the cost of missing the opportunity to make the market entry at the right time will prove too expensive for the latecomer in its competition against LCD.
This is a valuable lesson learned back in 2003. At that time, when TFT-LCD took on the mobile phone market, Sony was the only manufacturer who released AMOLED models. Although Samsung SDI finished the development of the bottom emission AMOLED, they had to just leave it there for the next five years after failing to make an investment in time; thus, finding themselves unable to catch up with the falling price of TFT-LCD. The OLED industry faced the toughest period since its inception – the situation was so bad that one could say AMOLED might have not existed, had Apple not launched the iPhone. Similarly, if AMOLED is released too late into the 3D TV market, the same situation could arise.
To produce AMOLED with 8th generation equipment, the manufacturing technology for both backplane and deposition need upgrading from the current level. CMOS-type backplane manufacturing, which is anticipated to be applicable to the 8th generation production technology, either split scans by expanding ELA technology that has currently evolved into 5.5th generation, or uses oxide TFT technology; ELA is already adopted in AMOLED manufacturing, whereas oxide TFT is still in the development stage. ELA will probably prove more advantageous for the 8th generation technology. Also, although PMOS backplane technology is favorable for large dimension, CMOS is more likely to be applied to 3D products.
In general, CMOS allows for higher resolution for AMOLED than PMOS does. Even though PMOS could have more advantages for bigger screens, high definition is essential in reproducing 3D images.
Most displays currently under development divide the screen into two – one for the left eye and the other for the right for 3D images – hence, the resolution drops by half when applying 3D technology to 2D. To display full HD 3D images, therefore, CMOS could be the technology of choice.
The challenge is with deposition equipment, however; no deposition equipment that could use 5.5th generation of glass substrate has been developed yet. It is possible to build such equipment, but the technology that uses shadow mask is a critical bottleneck in deposing the emitting materials. White OLED is the optimum technology among those that do not use fine metal shadow mask. Yet the material needs further development to be used for TV production.
For those reasons, a new concept of manufacturing technology should be soon prepared for mass production of large size AMOLED in 2013.
Samsung SMD has begun the development for such technology with an aim to make an early entry to the TV market. Kim Sang-su, the head of research center of Samsung SMD, moved to the development team to prepare the equipment and manufacturing process development for mass production of AMOLED TV.
The technology that Samsung is focusing on right now is called small mask scanning, or SMS. Despite using in-line deposition method and linear type source as the basis, this technology significantly reduced the length of the equipment and as well as processing time.
It cannot depose 8th generation glass substrate; however, the technology currently under development belongs to the 3rd generation well capable of manufacturing 40-inch TV. Once this technology is completed, AMOLED will be able to establish its position within the large-size 3D TV market. To be sure, it is still in the embryonic stage with many issues to be addressed, but the technology is noted as the most promising one for now. Samsung SMD boasts the best technology in the field, having led the large distribution of AMOLED, and a task on which even Japanese firms gave up on.
With the Vice President Kim Sang-su as the commander in chief, the troops are made up of exceptionally competent officials and developers with plentiful experience in backplane, deposition and equipment development from Samsung SDI era, raising high expectation from the AMOLED market.
One of the best display experts in the world, Kim Sang-su is a highly renowned engineer most noted for enlarging the size of LCD screens while he was working for Samsung Electronics and the winner of various technology awards and as well as Samsung Fellowship.
Many efforts have been made to differentiate AMOLED from LCD – the resolution and thickness, in particular, already exceeded those of LCD. The world is keeping an eye on the choices of AMOLED developers who are trying to dominate the display market in the upcoming age of 3D TV.
source: OLEDNET (www.olednet.com)