Tech Hardware Supply Chain - Gazhoo

Bhavin Shah
(852) 2800-8538
bhavin.a.shah@jpmorgan.com
290
Asia Pacific Equity Research
20 April 2009
Small-molecule OLED (SMOLED)
SMOLED requires vacuum evaporation technology, which makes SMOLED more
expensive than PLED, although the performance of SMOLED is better than other
OLED categories. It is also made on glass and not flexible at all. In SMOLED,
researchers in the OLED field have shifted their research focus in materials from
fluorescent materials to phosphorescent materials, because the electricity-to-light
conversion efficiency is only 25-50%, whereas the latter boasts of a conversion
efficiency of 80-100%. Rohm is a leading company in developing long-life
phosphorescent OLED. SONY, Pioneer, Seiko Epson, AUO, and Universal Display
Corp. (from the US) all have been working on OLED panels.
OLED categorization: Breakdown by driving method
Active matrix (AM) OLED displays stack cathode, organic, and anode layers on top
of another layer or substrate that contains circuitry. The pixels are defined by the
deposition of the organic material in a continuous and discrete ‘dot’ pattern. Each
pixel is activated directly—a corresponding circuit delivers voltage to the cathode
and anode materials, stimulating the middle organic layer. AMOLED pixels turn on
and off more than three times faster than the speed of conventional motion picture
film, making these displays ideal for fluid and full-motion video. The substrate, lowtemperature
polysilicon (LTPS) technology, transmits electrical current efficiently,
and its integrated circuitry cuts down the AMOLED display’s weight and cost.
Unlike PMOLED, AMOLED can individually switch on or off the pixels. In view of
the growing demand for high resolution and large area application, AMOLED is
expected to become the dominant force in the future OLED market, in our view.
Passive matrix (PM) OLED displays stack layers in a linear pattern, much like a
grid, with ‘columns’ of organic and cathode materials superimposed on ‘rows’ of
anode material. Each intersection or pixel contains all three substances. External
circuitry controls electrical current passing through the anode ‘rows’ and cathode
“columns”, stimulating the organic layer within each pixel. As pixels turn on and off
in sequence, pictures form on the screen. A PMOLED display’s function and
configuration are well-suited for viewing text and icons in dashboard and audio
equipment. Comparable to semiconductors in design, PMOLED displays are easily,
cost-effectively manufactured with today’s production techniques.
Low temperature poly-silicon (LTPS) and amorphous silicon (a-Si) are both
technologies integrating TFT on glass substrate. The obvious differences are electric
characteristics and the complexity of process. Companies developing AMOLED
technology are virtually all based on LTPS, although LTPS-TFT possesses higher
carrier mobility. This means more current can be supplied; the process is much more
complex and the yield is lower. However, the process of a-Si TFT is simple and
practiced, resulting in low cost, except for low carrier mobility.
Currently, most companies adopt low temperature poly silicon (LTPS)-based (AUO
has already switched its focus from amorphous Si to LTPS). Thus, TFT companies
which possess the LTPS technology become advantageous in the OLED industry.
Therefore, we can see a lot of strategic alliances between TFT and OLED companies.
For example, Tohoku Pioneer and ELDis, LG Electronics and LG Philips LCD, and
Prime View and Rit Display work together to cut into the OLED industry.