Valve position detection
A valve system for an ocular implant device includes a boss structure. The boss structure includes an inlet for fluid inflow, and a number of outlets for fluid outflow. The valve system further includes a deformable membrane positioned over and spaced apart from the inlet, the membrane comprising a piezo-based material, an actuating element to apply pressure to the membrane to deform the membrane into a position that obstructs fluid flow from the inlet, and a control system to detect a position of the membrane based on measured electrical properties of the membrane.
1. A valve system for an ocular implant device, the valve system comprising:
a housing;
a boss structure connected to the housing, the boss structure comprising an inlet for fluid inflow;
a number of outlets within the housing, the outlets for fluid outflow;
a displaceable membrane positioned over and spaced apart from the inlet, the membrane comprising a piezo-based material;
an actuating element to displace the membrane into a position that obstructs fluid flow from the inlet;
a control system to detect a position of the membrane based on measured electrical properties of the membrane.
2. The device of claim 1 , wherein the piezo-based material comprises a piezoelectric material.
3. The device of claim 1 , wherein the control system detects the position by measuring electric current flow during movement of the membrane.
4. The device of claim 1 , wherein the piezo-based material comprises a piezoresistive material.
5. The device of claim 4 , wherein the control system detects the position of the membrane by applying a voltage to the membrane and measuring current flowing through the membrane.
6. The device of claim 1 , wherein the membrane comprises an epitaxial grown semiconductor material.
7. The device of claim 1 , wherein the membrane comprises a semiconductor material doped with at least one of: boron, aluminum nitride, zinc oxide, lead zirconate titanate, silicon oxide, and chromium.
8. The device of claim 1 , wherein the control system uses a feedback control loop that uses a determined position of the membrane to move the membrane to a desired position.
9. The device of claim 1 , wherein the control system uses a feedback control system to control the actuating element and adjust fluid flow between the inlet and the outlets.
10. The device of claim 1 , wherein the actuating element utilizes electrolysis to apply pressure to the membrane.
11. A valve system for an ocular implant device, the valve system comprising:
a boss structure comprising:
an inlet for fluid inflow;
a number of outlets for fluid outflow; and
a displaceable membrane positioned over and spaced apart from the inlet, the membrane comprising:
a piezo-resistive layer;
an actuating element to adjust a position of the membrane to adjust fluid flow between the inlet and the outlets;
a sensor to detect an electrical characteristic of the membrane; and
a control system to determine the position of the membrane based on a measured electrical property of the membrane.
12. The device of claim 11 , wherein the sensor comprises:
a voltage supply to apply an excitation voltage to the membrane; and
a current measuring device to measure an electric current flowing through the membrane.
13. The device of claim 11 , wherein the control system comprises:
a processor; and
a memory comprising machine readable instructions, that when executed by the processor, cause the processor to:
store a set of data comparing electrical resistance through the membrane to position of the membrane;
make a comparison between a measured value and the data; and
output a corresponding position value based on the comparison.
14. The device of claim 11 , wherein the actuating element is configured to stop applying pressure when the membrane gets to a predetermined position.
15. The device of claim 11 , wherein the actuating element is configured to change application of pressure in respond to the control system determining that the membrane is not in an intended position.
16. A system for determining a position of a valve in an ocular implant, the system comprising:
a voltage supply in electrical connection with a piezoresistive membrane, the membrane being deformable between an open position that allows fluid flow between an inlet and a number of outlets, and a closed position that obstructs flow between the inlet and the outlets;
an electric current sensor in connection with the piezoresistive membrane, the electric current sensor configured to measure an electric current flowing through the membrane as a result of a voltage applied by the voltage supply to the membrane; and
a control system to determine a position of the membrane based on a measured electric current value and the voltage applied by the voltage supply.
17. The system of claim 16 , wherein to determine the position of the membrane, the control system is configured to:
compare the measured electric current with a set of data that correlates electric current values to positions of the piezoresistive membrane; and
output a position value that corresponds to the measured electric current.
18. The system of claim 16 , wherein to determine the position of the membrane the control system is configured to apply a function to the measured electric current, the function relating electric current to position of the membrane.
19. The system of claim 16 , further comprising, an actuating element configured to change its position at the piezoresistive membrane.
20. The system of claim 16 , wherein the control system is further configured to:
at a repeating time interval, determine a position of the membrane; and
adjust the position of the membrane if the membrane is not in a desired position.