Active material apparatus with activating thermoelectric device thereon and method of fabrication
View Patent ↗An active material assembly is provided having a thermally-activated active material apparatus with an elongated, non-planar shape and a thermoelectric device in thermal contact therewith. The thermoelectric device is characterized by a thermal differential when current flows through the device to activate the thermally-activated active material apparatus, thereby altering at least one dimension thereof. Multiple discrete thermoelectric devices may be in thermal contact with the active material apparatus and electrically in parallel with one another. The active material apparatus, which may be multiple active material components, each with one of the thermoelectric devices thereon, may be encased within a flexible electronic-insulating material to form an articulated active material assembly that can achieve different geometric shapes by separately activating one or more of the different thermoelectric devices. A method of fabricating an articulated active material assembly is also provided.
1. An active material assembly comprising:
a first and a second thermally-activated active material apparatus;
a first thermoelectric device in thermal contact with the first thermally-activated active material apparatus and characterized by a first thermal differential when current flows through the first thermoelectric device; wherein the first thermally-activated active material apparatus is activated in response to the first thermal differential to alter at least one physical property of the first thermally-activated active material apparatus;
a second thermoelectric device in thermal contact with the second thermally-activated active material apparatus and characterized by a second thermal differential when current flows through the second thermoelectric device; wherein the second thermally-activated active material apparatus is activated in response to the second thermal differential to alter at least one characteristic of the second thermally-activated active material apparatus;
a first electronic-insulating layer surrounding each of the thermoelectric devices and the first and the second active material apparatus to thereby connect the first and the second active material apparatus as a unit; wherein the first active material apparatus is spaced from the second active material apparatus within the first electronic-insulating layer with the first electronic-insulating layer between the first and the second thermoelectric devices;
a second electronic-insulating layer positioned between the first thermally-activated active material apparatus and the first thermoelectric device and having a generally electronic-insulating characteristic to insulate the first thermally-activated active material apparatus from current flow in the first thermoelectric device; and wherein the second electronic-insulating layer is a shape memory polymer configured to change length in the same direction as the first and the second thermally-activated active material apparatus in response to heat.
2. The active material assembly of claim 1 , wherein the first thermoelectric device includes at least one negatively-doped thermoelement and at least one positively-doped thermoelement connected electrically in series and thermally in parallel with one another.
3. The active material assembly of claim 1 , wherein the first thermoelectric device includes a first metal contact layer positioned between the second electronic-insulating layer and the thermoelements.
4. The active material assembly of claim 1 , wherein the first thermally-activated active material apparatus is a shape memory material; and wherein the first metal contact layer is a shape memory alloy.