Patent giveaway - Credit cards with screens

With rising levels of consumer debt plaguing the nation, here's a free idea for the banks and credit card companies: make credit cards with a digital read-out. A little LCD screen would do the job, or even better, why not incorporate the new eInk technology.

You see, although credit cards are very convenient, they don't provide you with any information about how much you've spent or how much you've got left to spend. (At least with cash, you can feel your wallet lighten with each purchase.) A little screen built into a credit card could make your financial info available at a glance.

It's such a good idea (if i do say so myself) that I'm surprised it hasn't been invented already.

Now, a cynical person might suggest that the banks and credit companies actually prefer us to be unaware of our spending. But that couldn't be the case, could it? My bank is forever telling me how committed it is to providing me with choice, freedom, and financial security. My bank loves me, and only wants the best for me. So I'm sure it's only a matter of time before we see this technology readily available.

UPDATE 15/11/07: In fact it looks like Visa are planning something like this (or at least were) according to a 2004 report from Engadget.com.