Micro rectangular heating element for thin layer heating

developmentpeltierresistors

The purpose

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.

Problem domain

The problem that I need help with

  1. Reasonably sized case within the range of units of centimetres.
  2. \$1mm \times 20mm\$ heating element (1mm or less if possible to increase efficiency)
  3. A circuit serving the heating element
  4. 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.

1. Termistor

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.

Best Answer

You could use a Polyimide etched-foil thin-film heater such as those made by Minco.

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As far as refrigeration goes, if this was a serious high-volume application I'd be looking at something other than Peltier modules, probably completely out of the EE realm. Peltiers are just too inefficient and have too much thermal mass.