Couple of major issues with this (as an EE who has designed products involving both RFID and E-Ink):
1. E-Ink requires a controller -- you can't get those at wafer scale
2. E-ink has a hard plastic substrate, you can't have it on a flexible substrate therefore it will break very easily under pressure.
3. E-ink requires 1mW to switch + power to the controller chip... RFID can't provide that much power.
4. You can use an NFC equipped phone to do the same thing, much easier (but that has its own issues)
5. E-ink is expensive. It will cost at least $20 in volume for a small display the size of your CC -- even a 120x72 strip will be about $10.
5. You can't easily interface the RFID chips with an e-ink display. Those RFID chips (MiFare DESFIRE, etc.) are all effectively enhanced memories. There is no processing power that you can control to interface w/ an e-ink display.
1. Yep, e-paper does require a controller. We're developing one at the appropriate thickness.
2. It's reasonably conformable, but it doesn't need to be any more so than the plastic substrate of e.g. an Oyster card.
3. That number strikes me as a little off, but in any event we're comfortable with the differential between the power we've got coming off the coil and what the display + controller need.
4. Agreed - but that's a different use case entirely.
5. You'd be amazed what volume can do.
6. Again, we're developing a custom controller.
What kind of an engineer looks at a situation like the one you describe and sees it as anything but a tasty challenge, anyway? : . )
Thanks for taking the time to think this through, though.
I'm not trying to be a naysayer. I'm trying to give you info because we've done a number of RFID and e-ink designs and I'm very familiar with both technologies. Neither of our designs involve a card.
BTW, some credit cards Visa is doing a field trial with have a display but it is LCD COG + Polymer battery for exactly the e-ink restrictions I've laid out below.
1. To fit inside a card you'll need wafer level thickness. Any package will be at least 2mm thick.
2. The screen will break if you put any force on it. I have dozens of samples of this to show you. Get a kindle, take the screen out, use a a dremel to cut it down into a card size, now put it in your wallet and sit on it.
3. That number is actually a low ball. We're seeing close to 2mW for switching. 1mW is from the datasheet. We turn on the controller, update the scree and go back to sleep -- close to 2.8mW gone. Also switching requires +25, -25 and a VCOM, I'd love to see how you're going to put a dual supply charge pump in such a small package and power it from a coil.
4. --
5. Well the pricing we have is for 100K volume but maybe you guys can get it down to couple of cents.
6. E-Ink requires custom waveforms which you can only get under license from PVI. They don't even give it to Epson, Motorola, or TI. You put the controller then e-ink gives you a file w/ the waveforms for that batch of screens.
Also, the e-ink display + substrate is much thicker than you think. Even their segmented display stuff which has much simpler requirements can't be driven off of what you want to drive it off of.
No one minds a challenge, provided the circumstances are realistic. Anyhow, good luck with the project.
3 comments
[ 3.8 ms ] story [ 17.9 ms ] thread1. E-Ink requires a controller -- you can't get those at wafer scale
2. E-ink has a hard plastic substrate, you can't have it on a flexible substrate therefore it will break very easily under pressure.
3. E-ink requires 1mW to switch + power to the controller chip... RFID can't provide that much power.
4. You can use an NFC equipped phone to do the same thing, much easier (but that has its own issues)
5. E-ink is expensive. It will cost at least $20 in volume for a small display the size of your CC -- even a 120x72 strip will be about $10.
5. You can't easily interface the RFID chips with an e-ink display. Those RFID chips (MiFare DESFIRE, etc.) are all effectively enhanced memories. There is no processing power that you can control to interface w/ an e-ink display.
What kind of an engineer looks at a situation like the one you describe and sees it as anything but a tasty challenge, anyway? : . )
Thanks for taking the time to think this through, though.
BTW, some credit cards Visa is doing a field trial with have a display but it is LCD COG + Polymer battery for exactly the e-ink restrictions I've laid out below.
1. To fit inside a card you'll need wafer level thickness. Any package will be at least 2mm thick.
2. The screen will break if you put any force on it. I have dozens of samples of this to show you. Get a kindle, take the screen out, use a a dremel to cut it down into a card size, now put it in your wallet and sit on it.
3. That number is actually a low ball. We're seeing close to 2mW for switching. 1mW is from the datasheet. We turn on the controller, update the scree and go back to sleep -- close to 2.8mW gone. Also switching requires +25, -25 and a VCOM, I'd love to see how you're going to put a dual supply charge pump in such a small package and power it from a coil.
4. --
5. Well the pricing we have is for 100K volume but maybe you guys can get it down to couple of cents.
6. E-Ink requires custom waveforms which you can only get under license from PVI. They don't even give it to Epson, Motorola, or TI. You put the controller then e-ink gives you a file w/ the waveforms for that batch of screens.
Also, the e-ink display + substrate is much thicker than you think. Even their segmented display stuff which has much simpler requirements can't be driven off of what you want to drive it off of.
No one minds a challenge, provided the circumstances are realistic. Anyhow, good luck with the project.