LTPSi versus amorphous Si
LTPSi is the next wave in LCD. Poly-Si permits much higher current density to flow through thin film transistors fabricated on glass, because the polySi has higher crystal quality than amorphous.
Camcorder screens and projection display SLMs are today made using pSi on quartz glass substrates with a high temp. process. Quartz is needed to withstand the elevated annealing temperature which recrystallizes the Si deposited in initially amorphous form. Quartz glass comes in smaller sizes and costs more than regular glass, and the high temperature process steps add cost to the overall process.
To understand the advantage of pSi over aSi, consider a single LCD pixel. It is a window, part of which is blocked by the thin film transistor which turns opens and closes the window. As certain amount of charge is needed to open the window, which the transistor must deliver. A pSi transistor, capable of much higher current density, can be much smaller, and therefore leaves more window space versus opaque transistor space. Thus, pSi permits smaller pixel sizes, since the smaller transistor means the pixel can shrink, while the aperture ratio (window area vs. transistor area),proportional to the optical efficiency, can remain high.
Given the added cost of HTpSi vs aSi and pSi's ability to go to smaller pixel sizes, ie higher pixel density, it makes sense to use pSi LCD in applications where a small high resolution display is needed, and a good price can be had. These markets are the camcorder and projection display today.
LTpSi permits the transistors to be fabricated nearly as well as with HTpSi, but on conventional glass. It should replace aSi altogether in five years or less since LTpSi is roughly equal cost, but better transistor performance. Using LTpSi, a 14" monitor can have many more pixels, or many more SLMs can be fabricated on a std. piece of glass.
In a previous post, I noted that a 14" FPD costs something like $1000 today, or next year,whatever. Assuming in three years, Moore's law brings this price down to $500 in three years using 1m2 glass and introducing LTpSi in favor of aSi at no cost disadvantage, then a 2" diagonal display can be manufactured using the same process at 1/49 the price, give or take. Thus, I predict that the $10 personal high resolution display three years out will be a LTpSi/glass one.
Kopin had better get ready to duck. They tout a pie in the sky $16 price for their display manufactured using Si wafers, but I calculate their present cost as more like 4X that, and to get to $16 they need high yield from an 8" process. They also need more optics in their package to make up for their smaller monitor size. Shorting Kopin is easy money in the long run, but I suggest waiting until its next irrationally exhuberant runup.
Reflective LCD/Si, such as TFS' approach, is in my opinion suited only for the higher end markets. Since the transistor is under the reflector, instead of blocking the window as with glass substrates, reflective LCD/Si can reach yet higher pixel densities to recover higher areal cost of the display. Niche's will be available for Kopin and TFS where users don't want a 2" display for a 2" image, but I feel the greater bulk of the personal display market will be taken by direct view 2-3" panels which open to the side of the unit, like camcorders today.
TFS can also play in the higher end projection market, but I think IBM is way ahead of them technologically and in market acceptance, TI's technology is interchangeable, entrenched and ramping up rapidly, and HTpSi LCD shows no signs of letting up either.
If you want to own TFS, do so because you believe their low margin passive matrix products will see good growth. I don't believe that TFS deserves much of a high tech premium, as others on this thread argue, since their core product is nearly a commodity one. In fact, if my predictions about LTpSi play out as above, TFS could join Kopin in my short column (I've never bought/sold TFS), since their core business would be obsoleted (or moved down the food/margin chain) as people begin to demand equivalent sized pSi displays having far superior resolution in their cellphones. Investors in TFS should be very wary of LTpSi developments I argue, and keep a sharp eye on whether R&D has any answers to LTpSi in the pipeline.
The is no stock market play for LTpSi. It's all in Japan, folded into the big conglomerates, especially Toshiba who will roll it out first.
The best US play on the display industry is shorting Kopin above $20, each and every time is gets over that point. Kopin has no display business at present, and little foreseeable business in the future, and certainly not enough for it to reduce its cost to its rosy $16 projection. Even if they could, they'd be undersold by LTpSi in three years at the outside. |
