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Now I think this is a difficult-to-implement idea too, but not for the reasons you mentioned

1. eink can be made on flexible plastic and be very thin, and cheap too (see http://www.engadget.com/2008/09/08/esquires-e-ink-infused-ma...)

2. charge pumps can be made out of discrete components and the largest part is a coil, which can easily be laid flat and thin. You can also charge a ceramic cap (low self discharge) slowly and use it when you need to change screen contents, thus allowing you to have a smaller charge pump yet

3. PCBs can be made very thin (a cheap pcb fab I use will make 10 PCBs for $10 for me at 0.2mm thickness). And you can also make them on a flexcable that is thinner yet.

You are right about EMV though. It is supposed to be uncloneable.

1 comments

1. With respect to e-ink on a flexible substrate... it was announced but I've never seen it happen. I've dealt with e-ink fairly recently on two projects. They don't have a flexible design to sell you beyond prototype. and for custom sizes Their MOQ to begin exploring a custom option is 100K units.

2. There is no coil in a charge pump :). They use capacitors and switches. There is no inductor. For a charge pump to drive an eink like screen you need caps of about 10-20uF. I've designed about 3 different boards that drive high-res e-ink screens. You can't get those caps below 1mm at the very best.

3. Are you sure you are getting 0.2mm PCBs? That is only 8mils thick! Most standard PCBs are 62 mils ~ 1.5mm. Can you tell me who these guys are that would do super thin at prototype prices? I would want to use them (no sarcasm).

Minimum IPC thickness for 4 layer board (which is what you need for the EPSON driver to those e-inks) is 12 mils but even at that you'll have mechanical problems with that PCB. Credit card thickness FYI is 30 mils = 0.030".

What I would say to these guys is: "show me a prototype with the appropriate thickness. You have a prototype, right?"

A prototype is a requirement here. Seeing the team, I see no technical person, but two brand designers (just the people to make a great demo video). Not to say they don't have someone who can pull this off, but it is a thing that has not been done before exactly. Like Lockitron, Coin, and others before, the variety of physical interfaces involved plus the need for it to work 100% of the time make this non-trivial. This is not just a neat digital interface problem.