Transient energy release microdevices and methods

• US 5,367,878 A
• Filed: 12/10/1992
• Issued: 11/29/1994
• Est. Priority Date: 11/08/1991
• Status: Expired due to Fees

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Nottenburg, Richard N., Shiflett, Geoffrey R., Muntz, Eric P.
• Primary Examiner(s): Cole, Richard R.
• Assistant Examiner(s): HEYMAN, LEONARD
• Application Number:
  US07/989,054
• Time in Patent Office: 719 Days
• Field of Search: 60/516, 60/508, 60/513, 60/519, 60/523, 60/512, 200/83 R, 200/83 N, 200/83 P, 219/513, 219/511, 359/224, 359/230, 417/207, 417/209
• US Class Current: 60/512
• CPC Class Codes: F01B 29/00 Machines or engines with pertinent characteristics other than those provided for in preceding main groups
• CPC Class Codes: F02G 1/04 of closed-cycle type
• CPC Class Codes: F02G 2258/10 ceramic
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F15C 1/04 Means for controlling fluid streams to fluid devices, e.g. by electric signals or other signals, no mixing taking place between the signal and the flow to be controlled fluid information or pulse transducers F15B5/00; electric regulation with electro-fluid amplifiers G05B7/02; fluid operating means for indicating or recording members in measuring instruments G01D5/42; distribution or supply devices for servomotors with electrically-controlled pilot valves F15B13/043
• CPC Class Codes: F15C 5/00 Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• CPC Class Codes: F16K 2099/0094 Micropumps
• CPC Class Codes: F16K 99/0001 Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0015 Diaphragm or membrane valves
• CPC Class Codes: F16K 99/0034 Operating means specially adapted for microvalves
• CPC Class Codes: F16K 99/0057 the fluid being the circulating fluid itself, e.g. check valves
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 2001/0042 Bistable switches, i.e. having two stable positions requiring only actuating energy for switching between them, e.g. with snap membrane or by permanent magnet
• CPC Class Codes: H01H 2061/006 Micromechanical thermal relay
• CPC Class Codes: H01H 61/00 Electrothermal relays thermal switches not operated by electrical input, thermal switches with anticipating electrical input H01H37/00; thermally-sensitive members H01H37/32
• CPC Class Codes: H01H 67/22 Switches without multi-position wipers

Abstract

A microdevice in the form of an electrical switch. A microdevice for providing switching at a high repetition rate, including a cell divided into two chambers by a bistable movable membrane. A charge of gas in the cell and a source for directly heating the gas to increase the gas pressure and move the membrane, the source for heating including a pulsed source for generating transient gas pressure increases, with the cell including an arrangement for cooling the gas for reducing the gas pressure after an increase.

Claims

1. A microdevice for providing motion at a high repetition rate, including in combination:

a cell having a membrane separating the interior of said cell into two chambers, with at least a portion of said membrane movable;

a charge of gas in said cell; and

means for directly heating said gas selectively to increase the gas pressure in one of said chambers and move said membrane portion,

said means for heating including pulse means for generating transient gas pressure increases in a chamber;

said cell including means for cooling said gas for reducing the gas pressure;

with said movable membrane portion being bistable and having first and second stable positions and movable from one of said positions to the other of said positions by change in gas pressure in said chambers of said cell.

2. A microdevice as defined in claim 1 wherein said membrane is an electrical conductor, and said cell includes an electrical conducting wall portion, with said membrane positioned to contact said electrical conducting wall portion when said membrane is in one of said stable positions providing a single throw electrical switch.

3. A microdevice as defined in claim 1 wherein said means for heating includes a source of photons and means for directing said photons into said cell.

4. A microdevice as defined in claim 1 wherein said means for heating includes:

a thin film of resistance heating material on an inner surface of said cell; and

means for connecting a pulsed electric power source to said film.

5. A microdevice as defined in claim 1 wherein said means for heating includes excitation means for producing an electrical discharge in said gas in said cell.

6. A microdevice as defined in claim 1 including means defining a gas flow path around said membrane between said chambers.

7. A microdevice as defined in claim 1 wherein said membrane is an electrical conductor, and said cell includes an electrical conducting wall portion in each of said chambers, with said membrane contacting the electrical conducting wall portion of one of said chambers when said membrane is in one of said stable positions and contacting the electrical conducting wall portion of the other of said chambers when said membrane is in the other of said stable positions providing a double throw electrical switch.

8. A microdevice as defined in claim 1 wherein said pulse means includes means for generating transient gas pressure increases in a chamber at cycle times of not more than about 50 microseconds.

9. A microdevice as defined in claim 1 wherein said pulse means includes means for generating transient gas pressure increases in a chamber at cycle times of not more than about 5 microseconds.

10. A microdevice as defined in claim 1 wherein said movable membrane portion includes a reflector.

11. A microdevice as defined in claim 10 including means for directing a light beam through said cell onto said reflector and means for directing light reflected from said reflector through said cell to the exterior when said membrane is in one of said stable positions providing a single throw light switch.

12. A microdevice as defined in claim 10 including means for directing a light beam through said cell onto said reflector and means for directing light reflected from said reflector through said cell to the exterior when said membrane is in each of said stable positions providing a double throw light switch.

13. A switching circuit comprising a plurality of cells in a X-Y array having a plurality of X paths and a plurality of Y paths, with a separate cell connecting each X path to each Y path,

each of said cells comprising a microdevice having an electrical conducting membrane separating the interior of said cell into two chambers, with at least a portion of said membrane movable;

a charge of gas in said cell; and

means for directly heating said gas selectively to increase the gas pressure in one of said chambers and move said membrane portion,

said means for heating including pulse means for generating transient gas pressure increases in a chamber;

said cell including means for cooling said gas for reducing the gas pressure;

with said movable membrane portion being bistable and having first and second stable positions and movable from one of said positions to the other of said positions by change in gas pressure in said chambers of said cell, and

with said cell having an electrical conducting portion for contact by said membrane when said membrane is in one of said stable positions.

14. A microdevice as defined in claim 13 wherein said membrane is an electrical conductor, and said cell includes an electrical conducting wall portion, with said membrane positioned to contact said electrical conducting wall portion when said membrane is in one of said stable positions providing a single throw electrical switch.

15. A method for providing switching motion at a high repetition rate with a microdevice having a cell with a membrane separating the interior of the cell into first and second chambers, with at least a portion of the membrane movable in response to change in pressure in the chambers of the cell, and a charge of gas in the cell,

including the steps of:

directly heating the gas in the first chamber to increase the gas pressure in the first chamber and move the membrane portion in a first direction by generating a transient gas pressure increase in the first chamber;

providing cooling of the gas for reducing the gas pressure in the first chamber;

directly heating the gas in the second chamber to increase the gas pressure in the second chamber and move the membrane portion in the opposite direction by generating a transient gas pressure increase in the second chamber; and

providing cooling of the gas for reducing the gas pressure in the second chamber.

16. A method as defined in claim 15 including generating the transient gas pressure increases at cycle times of not more than about 50 microseconds.

17. A method as defined in claim 15 including generating the transient gas pressure increases at cycle times of not more than about 5 microseconds.

18. A method as defined in claim 15 including heating by directing photons from a photon source into the first chamber.

19. A method as defined in claim 15 including heating by connecting a pulsed electric power source to a thin film of resistance heating material on an inner surface of the cell.

20. A method as defined in claim 15 including heating by periodically producing an electrical discharge within said cell.