Tuesday, March 5, 2013

Flexible Glass Product 3 Years away


ZDNet is reporting that flexible glass products are still 3 years away. Flexible glass been offered for sale before. It was part of my product line in the mid 1990's and was already an old product then. The difference between Willow and Corning's previous flexible glass is that Willow is made with the same process used to make LCD substrates and has much better surface quality. There are two reasons for using a flexible glass substrate. One is cost reduction. (1) Roll-to-Roll processes are inherently lower cost than unitized production. However, roll-to-roll manufacturing is orders of magnitude harder to develop. This is especially true when manufacturing steps require specialized atmospheres. Added to this will be increased fab contamination from higher glass breakage with a spooled product; the bending puts the outer surface under some stress. As with all glass products, the edges are particularly susceptible to breakage but with a spool of glass, the breakage has much more glass that it can either propagate through and contaminate with micro-particles.

If, instead of cost reduction, the objective is (2) to merely make a flexible product, the spooled glass can be cut into sheets and handled like an ordinary substrate, only thinner. Shipping spools rather than individual sheets will result in some level of cost reduction but this may be off-set by higher breakage in glass and display manufacturing as well as transport breakage.

(2A)Also consider if the display will actually be flexible in use rather than just curved. If the objective is to make a curved display, rather than being flexible, it might be more beneficial to have a glass that can be reformed (sagged) at reasonable temperatures that will not spoil the TFT photolithography. Or, as with curved samuria sords (made from a straight piece of metal) it may be possible to heat treat or ion stuff the glass to develop a naturally cylindrical shape. The thinness of Willow will help with this.

The ZD Net article speculates that the product for flexible glass will be the iWatch. I expect this product may have a curved display that is not flexible, at least if it is an LCD rather than an OLED. I also would not assume that the first product of this type to come from Apple. Samsung had a standing request for Fusion drawn .1 mm glass (what is now called Willow) since flexible glass was first offered. They are also one of the leaders in OLED. They have been thinking about this for a good 20 years.

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