Piezoelectric micro-transducers, methods of use and manufacturing methods for same
First Claim
1. A micro-transducer comprising:
- a first membrane;
a second membrane comprising a first electrode, a second electrode, and a piezoelectric member disposed therebetween;
a fluid-tight cavity cooperatively formed between the first and second membranes; and
a working fluid disposed in the cavity, wherein the working fluid is a saturated mixture of vapor and liquid.
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Accused Products
Abstract
Various micro-transducers incorporating piezoelectric materials for converting energy in one form to useful energy in another form are disclosed. In one embodiment, a piezoelectric micro-transducer can be operated either as a micro-heat engine, converting thermal energy into electrical energy, or as a micro-heat pump, consuming electrical energy to transfer thermal energy from a low-temperature heat source to a high-temperature heat sink. In another embodiment, a piezoelectric micro-transducer is used to convert the kinetic energy of an oscillating or vibrating body on which the micro-transducer is placed into useful electrical energy. A piezoelectric micro-transducer also is used to extract work from a pressurized stream of fluid. Also disclosed are a micro-internal combustion engine and a micro-heat engine based on the Rankine cycle in which a single fluid serves as a working fluid and a fuel.
85 Citations
53 Claims
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1. A micro-transducer comprising:
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a first membrane;
a second membrane comprising a first electrode, a second electrode, and a piezoelectric member disposed therebetween;
a fluid-tight cavity cooperatively formed between the first and second membranes; and
a working fluid disposed in the cavity, wherein the working fluid is a saturated mixture of vapor and liquid. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A micro-transducer comprising:
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a first layer;
a second layer having piezoelectric properties and joined to the first layer so as to form a fluid-tight cavity therebetween; and
a working fluid contained within the cavity;
wherein thermal energy flowing into the micro-transducer causes the working fluid to expand, thereby distending the second layer for generating an electrical charge. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A structure having a plurality of micro-transducers, the structure comprising:
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a first major layer;
a second major layer juxtaposed to the first layer;
a plurality of fluid-tight cavities cooperatively formed between the first and second major layers;
a working fluid contained in the cavities;
a plurality of first electrodes carried by the first major layer at each of said cavities;
a plurality of piezoelectric members carried by the first electrodes at each of said cavities; and
a plurality of second electrodes carried by the piezoelectric members at each of said cavities;
wherein the first electrodes comprise a unitary first metallic layer overlaying the first surface, the plurality of piezoelectric members comprise a unitary piezoelectric layer overlaying the first metallic layer, and the plurality of second electrodes comprise a unitary second metallic layer overlaying the piezoelectric layer. - View Dependent Claims (16)
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17. A structure having a plurality of micro-transducers, the structure comprising:
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a first major layer;
a second major layer juxtaposed to the first layer;
a plurality of fluid-tight cavities cooperatively formed between the first and second major layers;
a working fluid contained in the cavities;
a plurality of first electrodes carried by the first major layer at each of said cavities;
a plurality of piezoelectric members carried by the first electrodes at each of said cavities; and
a plurality of second electrodes carried by the piezoelectric members at each of said cavities;
wherein the first major layer comprises a first substrate and the second major layer comprises a second substrate, the first substrate having a plurality of recessed portions defining first membranes of the micro-transducers, and the second substrate having a plurality of recessed portions aligned with the recessed portions of the first substrate and defining second membranes of the micro-transducers.
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18. A structure having a plurality of micro-transducers, the structure comprising:
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a continuous, first major layer;
a continuous, second major layer juxtaposed to the first layer;
a plurality of fluid-tight cavities cooperatively formed between the first and second major layers;
a working fluid contained in the cavities;
a plurality of first electrodes carried by the first major layer at each of said cavities;
a plurality of piezoelectric members carried by the first electrodes at each of said cavities;
a plurality of second electrodes carried by the piezoelectric members at each of said cavities; and
an intermediate layer disposed between the first and second major layers, the intermediate layer defining a plurality of recesses that define respective cavities between the first and second major layers. - View Dependent Claims (19)
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20. A structure having a plurality of micro-transducers, the structure comprising:
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a first major layer;
a second major layer juxtaposed to the first layer;
a plurality of fluid-tight cavities cooperatively formed between the first and second major layers;
a working fluid contained in the cavities;
a plurality of first electrodes carried by the first major layer at each of said cavities;
a plurality of piezoelectric members carried by the first electrodes at each of said cavities; and
a plurality of second electrodes carried by the piezoelectric members at each of said cavities;
wherein the working fluid is a saturated mixture of vapor and liquid.
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21. A micro-transducer, comprising:
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a first membrane;
a second membrane comprising a first electrode, a second electrode, and a piezoelectric member disposed therebetween;
a fluid-tight cavity cooperatively formed between the first and second membranes;
a working fluid disposed in the cavity; and
a low-temperature heat sink disposed adjacent the first membrane and a high-temperature heat source disposed adjacent the second membrane such that the transducer is operative as a micro-heat engine having a thermodynamic cycle, wherein thermal energy, flowing from the high-temperature heat source to the low-temperature heat sink through the micro-heat engine during the thermodynamic cycle, is converted into electrical energy. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. A micro-transducer, comprising:
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a first membrane;
a second membrane comprising a first electrode, a second electrode, and a piezoelectric member disposed therebetween;
a fluid-tight cavity cooperatively formed between the first and second membranes;
a working fluid occupying substantially the entire cavity; and
a low-temperature heat source disposed adjacent the second membrane and a high-temperature heat sink disposed adjacent the first membrane such that the transducer is operative as a micro-heat pump having a thermodynamic cycle, wherein electrical energy is consumed to transfer heat from the low-temperature heat source to the high-temperature heat sink. - View Dependent Claims (29, 30, 31, 32, 33)
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34. A micro-transducer, comprising:
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a body defining a fluid-tight cavity;
a compressible and expansible working fluid contained within and occupying the cavity, the body having a piezoelectric unit situated adjacent the cavity, and the piezoelectric unit being operable as an actuator to compress the working fluid whenever an electric field is applied to the piezoelectric unit and operable as a generator to generate an electric charge whenever the working fluid expands;
a heat source; and
a heat sink, the heat source and heat sink being positioned relative to the body such that thermal energy flowing from the heat source to the heat sink flows through the working fluid. - View Dependent Claims (35, 36, 37, 38, 39)
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40. An apparatus for converting energy in one form to energy in another form, the apparatus comprising:
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a first major layer; and
a second major layer juxtaposed to the first major layer, the first and second major layers forming a plurality of micro-transducers, each micro-transducer comprising a respective fluid-tight cavity formed between the first and second major layers, a compressible working fluid disposed in the cavity, and a respective piezoelectric unit formed on one of the first and second major layers. - View Dependent Claims (41, 42, 43, 44, 45)
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46. An energy-conversion apparatus, comprising:
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a first pair of first and second substrates forming a respective plurality of micro-transducers, each micro-transducer having a respective fluid cavity formed between the first pair of first and second substrates, a working fluid disposed in the fluid cavity, and a respective piezoelectric unit carried on one of the first and second substrates of the first pair; and
a second pair of first and second substrates forming a respective plurality of micro-transducers, each micro-transducer having a respective fluid cavity formed between the second pair of first and second substrates, a working fluid disposed in the fluid cavity, and a respective piezoelectric unit carried on one of the first and second substrates of the second pair, wherein the first pair of substrates is stacked superposedly with respect to the second pair of substrates. - View Dependent Claims (47, 48, 49)
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50. A micro-transducer, comprising:
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a body defining a fluid-tight cavity; and
a compressible and expansible working fluid contained within the cavity, the body having a piezoelectric unit situated adjacent the cavity, and the piezoelectric unit being operable as an actuator to compress the working fluid whenever an electric field is applied to the piezoelectric unit and operable as a generator to generate an electric charge whenever the working fluid expands. - View Dependent Claims (51, 52, 53)
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Specification