AU Optronics unveiled a 20-inch e-paper display at the recent FPD2009 (28 Oct 2009) along with their 6-inch flexible e-reader They claimed this was the world’s largest e-paper display that can be mass produced and so I was interested to see what technology was being used and what patents had been granted. It turns out that AUO are working with technology developed by Sipix and a quick look at the Sipix website provides a nice summary of the Microcup® technology and its use for electrophoretic displays.
The first patent applications for this approach were filed in 2000 but the granted patent that covers this technology is US7112114B2 which was published on 26th Sept 2006. The first claim reads:
1. A process for the preparation of a semi-finished display panel, which process comprises the steps of:
a) coating a layer of a thermoplastic, thermoset or precursor thereof on a temporary substrate layer followed by embossing the coated layer with a male mold or imagewise exposing a layer of a radiation curable composition coated on a temporary substrate layer followed by removing unexposed areas, to form an array of microcups;
b) filling the microcups with a charged pigment dispersion in a dielectric solvent or solvent mixture;
c) top-sealing the microcups; and
d) applying a conductor layer or a permanent substrate layer onto the top-sealed microcups.
Fig. 6 from the patent shows a schematic of the process: