Active temperature differential control

Apparatus for maintaining a particular temperature differential and/or adjustable temperature gradient between two, possibly variant domains on a first plate of different temperature comprising:

• a first active thermal element (heater or cooling element) in contact with said plate for adjusting the temperature of a first domain of said plate;
• a droplet made of a material having a thermal conductivity that is higher than the thermal conductivity of said plate;
• a second plate onto which the droplet rests in thermal contact therewith;
• a second active temperature means (heater or cooling element) on the second plate for determining the temperature of the droplet;
• and
• means for displacing the second and first plates in relation to each other to more or less flatten the droplet in between said first and second plates to thereby vary the area of contact between the top part of the droplet and said first plate.