Virtual valve in a MEMS-based cooling system

An active cooling system comprising:

• at least one cooling element having a vent therein and being in communication with a fluid, the at least one cooling element being actuated to vibrate to drive the fluid toward a heat-generating structure and to alternately open and close at least one virtual valve corresponding to the vent, the at least one virtual valve being open for a low flow resistance and closed for a high flow resistance, the vent remaining physically open for the virtual valve being closed;
• wherein the at least one cooling element consists of a first cooling element having the vent therein and a second cooling element, wherein the vent is a passive vent, the first cooling element and the second cooling element being in communication with the fluid, the second cooling element being between the first cooling element and the heat-generating structure, the second cooling element having an active vent therein, the at least one virtual valve including a passive virtual valve corresponding to the passive vent and an active virtual valve corresponding to the active vent, the passive virtual valve being open in a suction arrangement and closed in an expulsion arrangement, the active virtual valve being closed in the suction arrangement and open in the expulsion arrangement, the first cooling element and the second cooling element being driven to undergo vibrational motion to provide the suction arrangement and the expulsion arrangement such that the fluid is directed toward the heat-generating structure and such that the active vent and the passive vent remaining physically open throughout the vibrational motion, the vibrational motion being out-of-phase vibrational motion for the first cooling element and the second cooling element such that the passive vent of the first cooling element is distal from the second cooling element in the suction arrangement and proximate to the second cooling element in the expulsion arrangement, the passive vent being offset from the active vent.

An active cooling system comprising:

• at least one cooling element having a vent therein and being in communication with a fluid, the at least one cooling element being actuated to vibrate to drive the fluid toward a heat-generating structure and to alternately open and close at least one virtual valve corresponding to the vent, the virtual valve being open for a low flow resistance and closed for a high flow resistance, the vent remaining physically open for the virtual valve being closed;
• wherein the at least one cooling element includes a first cooling element and a second cooling element, the vent being a passive vent, the second cooling element being between the first cooling element and the heat-generating structure, the second cooling element having an active vent therein, the at least one virtual valve including a passive virtual valve corresponding to the passive vent and an active virtual valve corresponding to the active vent, the passive virtual valve being open in a suction arrangement and closed in an expulsion arrangement, the active virtual valve being closed in the suction arrangement and open in the expulsion arrangement, the passive vent being distal from the second cooling element in the suction arrangement, the passive vent being proximate to the second cooling element in the expulsion arrangement, at least one of the first cooling element and the second cooling element using vibrational motion to provide the suction arrangement and the expulsion arrangement such that the fluid is directed toward the heat-generating structure and such that the active vent and the passive vent remaining physically open throughout the vibrational motion;
• and
• wherein the first cooling element has a landing adjacent to the passive vent and wherein the second cooling element includes a plug opposite to the landing of the first cooling element.

An active piezoelectric cooling system comprising:

• a plurality of piezoelectric cooling cells, each of the plurality of piezoelectric cooling cells including at least one cooling element having a vent therein and being in communication with a fluid, the at least one cooling element being actuated to vibrate to drive the fluid toward a heat-generating structure and to alternately open and close at least one virtual valve corresponding to the vent, the at least one virtual valve being open for a low flow resistance and closed for a high flow resistance, the vent remaining physically open for the at least one virtual valve being closed, the at least one cooling element being at least one piezoelectric cooling element;
• wherein the at least one cooling element includes a first cooling element having the vent therein and a second cooling element, wherein the vent is a passive vent therein, the first cooling element and the second cooling element being in communication with the fluid, the second cooling element being between the first cooling element and the heat-generating structure, the second cooling element having an active vent therein, the at least one virtual valve including a passive virtual valve corresponding to the passive vent and an active virtual valve corresponding to the active vent, the passive virtual valve being open in a suction arrangement and closed in an expulsion arrangement, the active virtual valve being closed in the suction arrangement and open in the expulsion arrangement, the first cooling element and the second cooling element being driven to undergo vibrational motion to provide the suction arrangement and the expulsion arrangement such that the fluid is directed toward the heat-generating structure and such that the active vent and the passive vent remaining physically open throughout the vibrational motion, the vibrational motion being out-of-phase vibrational motion for the first cooling element and the second cooling element such that the passive vent is distal from the second cooling element in the suction arrangement and proximate to the second cooling element in the expulsion arrangement, the passive vent being offset from the active vent.