The main goal is creating a little hand-held device that would heat a thin film (locally) to \$50-70°C\$ by sliding over it. The film area is \$<150cm^2\$. A secondary goal would be to create a device with the same parameters that would cool the film down (locally) to \$<-28°C\$ to reverse the process.
The problem that I need help with
Reasonably sized case within the range of units of centimetres.
- \$1mm \times 20mm\$ heating element (1mm or less if possible to increase efficiency)
A circuit serving the heating element Battery
I don't want to heat the material itself (or I do, but very superficially, maybe 0.001mm in depth). This device has to be powered with a low capacity battery (e.g. 1700mAh, 1.5V) for as long as possible.
I came up with a couple of ideas, but I can't figure out the specific parameters and components to use.
As a self-regulating heating element, thermistor seems to be just perfect for this purpose. But what exact parameters should it have? Will it be effective enough? And where can I buy a thermistor with those specific parameters?
2. Peltier Module
Another solution that comes to my mind is using a Peltier Module. It uses a lot of power, but maybe if I make it small enough (by splitting a ready-made Peltier Module into separate rows?), maybe the input power wouldn't be so high. The questions about the thermistor apply here as well.