US4438364A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piezoelectric actuator
Assignee: Garrett Corp
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Filing: 1981-07-13
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Granted: 1984-03-20
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Expires: 2001-07-13
Abstract
Abstract A low voltage, high frequency actuator for correcting distortions in laser optics systems.
Inventors
- 👤 Rodney Morison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:37
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/0816; G02B26/0833; G02B26/0858; G02B26/0825; H; H10; H10N; H10N30/00; H10N30/50; H10N30/503; H10N30/505; H10N30/80; H10N30/85; H10N30/853; H10N30/8536; H10N30/88; H10N30/886
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
173 words
An actuator for producing a force on a load in response to a single polarity D.C. voltage, comprising: a stack of layers of a piezoelectric material having a central passage therethrough, each of the layers in said stack being not greater than 4 mils in thickness, each of said layers being poled to have an electrically positive surface and an electrically negative surface, said layers being positioned such that adjacent surfaces have like electrical polarities; a first electrode connected to said electrically positive surfaces; a second electrode connected to said electrically negative surfaces; means for applying a potential difference between said first and second electrodes to produce an electric field in each said layer, said electric field causing a force in each said layer along the length of said stack for positioning the load; and preload means wherein said preload means includes: an actuator rod passing through said central passage; a preload spring connected to said actuator rod; and means, connected to said actuator rod, for urging said preload spring against said stack.
Claim 2
Dependent Claim
173 words
An actuator for producing a force on a load in response to a single polarity D.C. voltage, comprising: a stack of layers of a piezoelectric material having a central passage therethrough, each of the layers in said stack being not greater than 4 mils in thickness, each of said layers being poled to have an electrically positive surface and an electrically negative surface, said layers being positioned such that adjacent surfaces have like electrical polarities; a first electrode connected to said electrically positive surfaces; a second electrode connected to said electrically negative surfaces; means for applying a potential difference between said first and second electrodes to produce an electric field in each said layer, said electric field causing a force in each said layer along the length of said stack for positioning the load; and preload means wherein said preload means includes: an actuator rod passing through said central passage; a preload spring connected to said actuator rod; and means, connected to said actuator rod, for urging said preload spring against said stack.
Claim 3
Dependent Claim
30 words
An actuator according to claim 1, wherein said electrically positive surface and said electrically negative surface of each of said elements are coated with a vacuum deposition of tungsten-gold film.
Claim 4
Dependent Claim
14 words
An actuator according to claim 2, wherein said film is approximately 6 micro-inches thick.
Claim 5
Dependent Claim
31 words
An actuator according to claim 2, wherein said electrically positive surface and said electrically negative surface of each of said elements are polished flat before being coated with said tungsten-gold film.
Claim 6
Dependent Claim
26 words
An actuator according to claim 1, wherein said actuator requires not greater than 200 VDC to achieve the maximum deformation along the length of said stack.
Claim 7
Dependent Claim
168 words
An actuator for selectively bending a laser mirror, comprising: a plurality of layers of a piezoelectric material, each of the layers in said plurality being not greater than 4 mils in thickness, each of said layers being electrically polarized to have an electrically positive surface and an electrically negative surface, said layers being positioned to form a stack such that adjacent surfaces have like electrical polarities; electrode means interdigitated between said layers for applying an electrical potential difference between said electrically positive surface and said electrically negative surface of each said layer; means for connecting one end of said stack to a laser mirror; means for preloading said stack to compress said stack and to deform said laser mirror to a predetermined configuration; and means for applying an electrical signal to said electrode means to produce an electric field in each said layer, said electric field producing a force in each said layer along the length of said stack for selectively varying the configuration of said laser mirror.
Claim 8
Dependent Claim
168 words
An actuator for selectively bending a laser mirror, comprising: a plurality of layers of a piezoelectric material, each of the layers in said plurality being not greater than 4 mils in thickness, each of said layers being electrically polarized to have an electrically positive surface and an electrically negative surface, said layers being positioned to form a stack such that adjacent surfaces have like electrical polarities; electrode means interdigitated between said layers for applying an electrical potential difference between said electrically positive surface and said electrically negative surface of each said layer; means for connecting one end of said stack to a laser mirror; means for preloading said stack to compress said stack and to deform said laser mirror to a predetermined configuration; and means for applying an electrical signal to said electrode means to produce an electric field in each said layer, said electric field producing a force in each said layer along the length of said stack for selectively varying the configuration of said laser mirror.
Claim 9
Dependent Claim
47 words
An actuator according to claim 6 wherein said preloading means deforms said laser mirror to a first predetermined configuration and wherein said electrical signal permits continuous variation of the configuration of said laser mirror from said first predetermined configuration to a second predetermined configuration of maximum convexity.
Claim 10
Dependent Claim
26 words
An actuator according to claim 6 wherein said preload means includes a preload spring and means for biasing said preload spring to compressively load said stack.
Claim 11
Dependent Claim
55 words
An actuator according to claim 8 wherein said stack has a central passage therethrough, further including: an actuator rod passing through said central passage; means for connecting an end of said actuator rod to said laser mirror whereby said means for biasing said preload spring will also deform said laser mirror to a predetermined configuration.
Claim 12
Independent Claim
127 words
A method for producing a force on a load, comprising the steps of: forming a stack of a plurality of poled piezoelectric layers, each poled piezoelectric layer in said stack being not greater than 4 mils in thickness and having an electrically positive surface and an electrically negative surface; connecting a first electrode to said electrically positive surfaces; connecting a second electrode to said electrically negative surfaces; preloading said stack for moving the load through a predetermined range of motion along the length of said stack; and applying a single polarity direct current potential difference between said first and second electrodes to produce an electric field in each said poled piezoelectric layer for causing a force therein along the length of said stack for moving said load.
Claim 13
Independent Claim
127 words
A method for producing a force on a load, comprising the steps of: forming a stack of a plurality of poled piezoelectric layers, each poled piezoelectric layer in said stack being not greater than 4 mils in thickness and having an electrically positive surface and an electrically negative surface; connecting a first electrode to said electrically positive surfaces; connecting a second electrode to said electrically negative surfaces; preloading said stack for moving the load through a predetermined range of motion along the length of said stack; and applying a single polarity direct current potential difference between said first and second electrodes to produce an electric field in each said poled piezoelectric layer for causing a force therein along the length of said stack for moving said load.
Claim 14
Dependent Claim
43 words
A method according to claim 10 further including the steps of: stacking said poled piezoelectrical layers such that adjacent surfaces have like electrical polarities; and interdigitating said first electrode and said second electrode between said electrically positive surfaces and said electrically negative surfaces.
Claim 15
Independent Claim
82 words
A method for forming a piezoelectric ceramic actuator comprising the steps of: forming a plurality of piezoelectric ceramic elements; coating a first face and an opposing second face of said piezoelectric ceramic elements by deposition with an electrically conducting film to form electrodes thereon; polarizing said piezoelectric ceramic elements to form electrically positive and negative surfaces on said first and second faces; stacking said piezoelectric ceramic elements with adjacent surfaces thereof having like electrical polarities; and compressively preloading said piezoelectric ceramic elements.
Claim 16
Independent Claim
82 words
A method for forming a piezoelectric ceramic actuator comprising the steps of: forming a plurality of piezoelectric ceramic elements; coating a first face and an opposing second face of said piezoelectric ceramic elements by deposition with an electrically conducting film to form electrodes thereon; polarizing said piezoelectric ceramic elements to form electrically positive and negative surfaces on said first and second faces; stacking said piezoelectric ceramic elements with adjacent surfaces thereof having like electrical polarities; and compressively preloading said piezoelectric ceramic elements.
Claim 17
Dependent Claim
25 words
A method according to claim 12 further including the step of placing a conducting shim between each pair of said surfaces having like electrical polarities.
Claim 18
Dependent Claim
52 words
A method according to claim 12, wherein said coating step comprises: depositing by vacuum deposition on said first face of said piezoelectric ceramic elements a tungsten-gold film approximately 6 micro-inches thick; and depositing by vacuum depositing on said second face of said piezoelectric ceramic elements a tungsten-gold film approximately 6 micro-inches thick.
Claim 19
Dependent Claim
23 words
A method according to claim 12, further including the additional step before said coating step of polishing said first and second faces flat.
Claim 20
Dependent Claim
20 words
A method according to claim 12, wherein each of said piezoelectric ceramic elements is not greater than 4 mils thick.
Claim 21
Dependent Claim
105 words
A piezoelectric actuator for producing a longitudinal force in response to single polarity D.C. control voltage varying from zero to a value not greater than 200 volts, comprising: a stack containing a plurality of thin, flat piezoelectric elements, each element in said plurality having flat, polished planar surfaces; means for compressively preloading said stack; a thin film of tungsten-gold material deposited upon said planar surfaces of each said element; and means for electrically connecting said elements in parallel to two input terminals, the planar surfaces of each pair of adjacent elements in said stack being connected to the same one of said two input terminals.
Claim 22
Dependent Claim
105 words
A piezoelectric actuator for producing a longitudinal force in response to single polarity D.C. control voltage varying from zero to a value not greater than 200 volts, comprising: a stack containing a plurality of thin, flat piezoelectric elements, each element in said plurality having flat, polished planar surfaces; means for compressively preloading said stack; a thin film of tungsten-gold material deposited upon said planar surfaces of each said element; and means for electrically connecting said elements in parallel to two input terminals, the planar surfaces of each pair of adjacent elements in said stack being connected to the same one of said two input terminals.
Claim 23
Dependent Claim
19 words
A piezoelectric actuator according to claim 17, wherein each of said elements are not greater than 4 mils thick.
Claim 24
Dependent Claim
37 words
A piezoelectric actuator according to claim 17, wherein said stack is polarized by application of a D.C. voltage of the same polarity and approximately twice the magnitude of said D.C. control voltage to said two input terminals.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |