Patent ID: 7766033

Claim:
A microfluidic latching valve structure comprising: an input to the structure; first, second and third membrane valves, each valve including a valve input, a valve output, a valve control, and an elastomer membrane configured such that the application of a pressure or a vacuum to the valve control causes the membrane to deflect to modulate a flow of fluid through the valve; and wherein: (i) the input to the structure is configured to transmit pressure or vacuum to the valve input of the first membrane valve and to the valve input of the second membrane valve, (ii) the valve outputs of the first and second membrane valves are in communication through a microfluidic channel when the first and second membrane valves are closed, and (iii) the valve outputs of the first and second membranes valve are in communication with the valve control of the third membrane valve and the valve outputs of the first and second membrane valves are configured to transmit the pressure or vacuum to the valve control of the third membrane valve, such that a sufficient vacuum at the input to the structure causes the third membrane valve to open and upon removal of the vacuum, the third membrane valve remains open and such that a sufficient pressure at the input to the structure causes the third membrane valve to close and upon removal of the pressure, the third membrane valve remains closed.