US4089034A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Machine and method for poling films of pyroelectric and piezoelectric material
Assignee: 3M Co
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Filing: 1976-04-30
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Granted: 1978-05-09
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Expires: 1996-04-30
Abstract
Abstract An apparatus and method for rapidly and continuously poling a film of polymeric material exhibiting at least one of pyroelectric and piezoelectric characteristics to yield a poled film having a high coefficient of at least one of pyroelectric and piezoelectric properties, and a high degree of uniformity of polarization throughout its thickness. The method of the present invention includes applying a plurality of time-spaced electric field pulses across a portion of the film. The apparatus of the present invention includes a drive for advancing the film and a pair of electrodes that establish an electric field across the film. A hot poling roller serves as a high voltage electrode and a grounded roller contacts a conductive layer coated on the other side of the film. A voltage source and a switch coact to apply a plurality of time-spaced electric field pulses between the two electrodes. The width of each pulse is less than the time a portion of the film is under the influence of the electric field established by the two electrodes. The high voltage electrode is separated from direct physical contact with the film by a resistive layer in order to avoid serious damage to the film due to electrical arcing that can occur through a defective or thinner than normal area of the film.
Inventors
- 👤 Allen L. Taylor
- 👤 William F. Sheffield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:45
CPC Classifications
H; H10; H10N; H10N30/00; H10N30/01; H10N30/04; H10N30/045; H10N30/09; H10N30/098; H10N30/80; H10N30/85; H10N30/857; Y; Y10; Y10T; Y10T29/00; Y10T29/43; Y10T29/435
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
181 words
A poling apparatus for continuously processing a length of film of polymeric material to provide at least one of pyroelectric and piezoelectric properties in the film, comprising: a first means at a poling station for applying an electric potential to at least a portion of one broad surface of the film; a second means located at the poling station for coacting with said first means to establish an electric field across said portion of the film to provide moderate coefficients of at least one of said pyroelectric and piezoelectric properties in said portion; a drive means for continuously advancing the film past the poling station; and a third means electrically connected to said first and second means for providing electric potentials to said first and second means to establish a plurality of time-spaced electric field pulses across said portion of the film while it is advancing past the poling station, the width of each said pulse being less than the time said portion of the film is under the influence of the electrical field established by said first and second means.
Claim 2
Dependent Claim
181 words
A poling apparatus for continuously processing a length of film of polymeric material to provide at least one of pyroelectric and piezoelectric properties in the film, comprising: a first means at a poling station for applying an electric potential to at least a portion of one broad surface of the film; a second means located at the poling station for coacting with said first means to establish an electric field across said portion of the film to provide moderate coefficients of at least one of said pyroelectric and piezoelectric properties in said portion; a drive means for continuously advancing the film past the poling station; and a third means electrically connected to said first and second means for providing electric potentials to said first and second means to establish a plurality of time-spaced electric field pulses across said portion of the film while it is advancing past the poling station, the width of each said pulse being less than the time said portion of the film is under the influence of the electrical field established by said first and second means.
Claim 3
Dependent Claim
41 words
A poling apparatus according to claim 1, wherein said third means comprises: a first high voltage source; a second high voltage source; and switch means for alternately connecting said first and second high voltage sources between said first and second means.
Claim 4
Dependent Claim
24 words
A poling apparatus according to claim 1, wherein the width of each said pulse provided by said third means is less than 2 seconds.
Claim 5
Dependent Claim
24 words
A poling apparatus according to claim 1, wherein the width of each said pulse provided by said third means is less than 500 milliseconds.
Claim 6
Dependent Claim
24 words
A poling apparatus according to claim 1, wherein the width of each said pulse provided by said third means is less than 100 milliseconds.
Claim 7
Dependent Claim
26 words
A poling apparatus according to claim 1, wherein said plurality of time-spaced electric field pulses provided by said third means is at least four in number.
Claim 8
Dependent Claim
23 words
A poling apparatus according to claim 1, wherein said plurality of pulses provided by said third means is at least 10 in number.
Claim 9
Dependent Claim
28 words
A poling apparatus according to claim 1, wherein said electric field pulses provided by said third means provide a magnitude greater than 1500 K volts/cm. across said film.
Claim 10
Dependent Claim
28 words
A poling apparatus according to claim 1, wherein said electric field pulses provided by said third means provide a magnitude greater than 2500 K volts/cm. across said film.
Claim 11
Dependent Claim
31 words
A poling apparatus according to claim 9, wherein the electric field provided by said third means in the time-space between said pulses is less than 2400 K volts/cm. across said film.
Claim 12
Dependent Claim
28 words
A poling apparatus according to claim 9, wherein the electric field provided by said third means in the time-space between said pulses is less than 2000 K volts/cm.
Claim 13
Dependent Claim
40 words
A poling apparatus according to claim 1, wherein said third means provides at least 4 pulses across said portion of the film, each pulse having a width less than 2 seconds and a maximum magnitude greater than 1500 K volts/cm.
Claim 14
Dependent Claim
49 words
A poling apparatus according to claim 1, wherein said first means includes a cylindrical roller having a grounded electrically conductive surface for contacting a layer of conductive material carried on said one surface of the film; and said second means includes a cylindrical roller having an electrically conductive surface.
Claim 15
Dependent Claim
27 words
A poling apparatus according to claim 13, further including a current limiting means that is carried on the surface of said cylindrical roller of the second means.
Claim 16
Dependent Claim
30 words
A poling apparatus according to claim 14, wherein said second means provides heat for raising the temperature of said portion during the time it is influenced by said electric field.
Claim 17
Dependent Claim
40 words
A poling apparatus according to claim 1, wherein said first and second means establish an electric field across said portion of the film to provide considerably coefficients of at least one of said pyroelectric and piezoelectric properties in said portion.
Claim 18
Dependent Claim
40 words
A poling apparatus according to claim 1, wherein said first and second means establish an electric field across said portion of the film to provide substantial coefficients of at least one of said pyroelectric and piezoelectric properties in said portion.
Claim 19
Dependent Claim
146 words
A process for continuously poling a film of polymeric material to provide at least one of pyroelectric and piezoelectric properties in the film, comprising: advancing said film past a poling station that includes a poling electrode; applying a first electric potential to at least a portion of one broad surface of the film; and applying a second electric potential to said portion on the opposite broad surface of the film to establish an electric field having a plurality of time-spaced electric field pulses across said portion of the film while it is advancing past the poling station to provide moderate coefficients of at least one of said pyroelectric and piezoelectric properties in said portion, the width of each said pulse being less than the time said portion of the film is under the influence of the electric field established by said first and second electric potentials.
Claim 20
Dependent Claim
146 words
A process for continuously poling a film of polymeric material to provide at least one of pyroelectric and piezoelectric properties in the film, comprising: advancing said film past a poling station that includes a poling electrode; applying a first electric potential to at least a portion of one broad surface of the film; and applying a second electric potential to said portion on the opposite broad surface of the film to establish an electric field having a plurality of time-spaced electric field pulses across said portion of the film while it is advancing past the poling station to provide moderate coefficients of at least one of said pyroelectric and piezoelectric properties in said portion, the width of each said pulse being less than the time said portion of the film is under the influence of the electric field established by said first and second electric potentials.
Claim 21
Dependent Claim
26 words
A continuous poling process according to claim 18, wherein the width of each said pulse across said portion of the film is less than 2 seconds.
Claim 22
Dependent Claim
19 words
A continuous poling process according to claim 18, wherein the width of each pulse is less than 500 milliseconds.
Claim 23
Dependent Claim
20 words
A continuous poling process according to claim 18, wherein said plurality of time-spaced pulses is at least four in number.
Claim 24
Dependent Claim
19 words
A continuous poling process according to claim 18, wherein said plurality of pulses is at least 10 in number.
Claim 25
Dependent Claim
20 words
A continuous poling process according to claim 18, wherein said pulses have a maximum magnitude greater than 1500 K volts/cm.
Claim 26
Dependent Claim
20 words
A continuous poling process according to claim 18, wherein said pulses have a maximum magnitude greater than 2500 K volts/cm.
Claim 27
Dependent Claim
24 words
A continuous poling process according to claim 24, wherein the electric field in the time-space between said pulses is less than 2400 K volts/cm.
Claim 28
Dependent Claim
40 words
A continuous poling process according to claim 18, wherein said plurality of time-spaced electric field pulses are at least four in number, each pulse having a width less than 2 seconds and a maximum magnitude greater than 1500 K volts/cm.
Claim 29
Dependent Claim
27 words
A continuous poling process according to claim 26, wherein said pulse has a width less than 500 milliseconds and a maximum magnitude greater than 2500 K volts/cm.
Claim 30
Dependent Claim
53 words
A continuous poling process according to claim 18, further including the steps of: heating said portion concurrent with the establishment of the electric field across said portion; and cooling said portion while said polymeric material has moderate coefficients of at least one of said pyroelectric and piezoelectric properties produced by said electric field.
Claim 31
Dependent Claim
15 words
A continuous poling process according to claim 18, wherein said polymeric material is polyvinylidene fluoride.
Claim 32
Dependent Claim
34 words
A continuous poling process according to claim 18, wherein applying said electric field having a plurality of time-spaced electric field pulses provides considerable coefficients of at least one of said pyroelectric and piezoelectric properties.
Claim 33
Dependent Claim
34 words
A continuous poling process according to claim 18, wherein applying said electric field having a plurality of time-spaced electric field pulses provides substantial coefficients of at least one of said pyroelectric and piezoelectric properties.
Claim 34
Dependent Claim
119 words
A process for poling a film of polymeric material to provide at least one of pyroelectric and piezoelectric properties in the film, comprising: applying an electric field across a portion of the film for a time sufficient to provide at least one of said pyroelectric and piezoelectric properties in said portion; wherein the improvement comprises: applying an electric field having a plurality of time-spaced electric field pulses across said portion of the film to provide moderate coefficients of at least one of said pyroelectric and piezoelectric properties, the width of each pulse being less than 5 seconds, the spacing between pulses being greater than 100 milliseconds, and the maximum magnitude of each pulse being greater than 1500 K volts/cm.
Claim 35
Dependent Claim
119 words
A process for poling a film of polymeric material to provide at least one of pyroelectric and piezoelectric properties in the film, comprising: applying an electric field across a portion of the film for a time sufficient to provide at least one of said pyroelectric and piezoelectric properties in said portion; wherein the improvement comprises: applying an electric field having a plurality of time-spaced electric field pulses across said portion of the film to provide moderate coefficients of at least one of said pyroelectric and piezoelectric properties, the width of each pulse being less than 5 seconds, the spacing between pulses being greater than 100 milliseconds, and the maximum magnitude of each pulse being greater than 1500 K volts/cm.
Claim 36
Dependent Claim
39 words
A process according to claim 32, wherein the width of each pulse is less than 500 milliseconds, the spacing between pulses is greater than 500 milliseconds and the maximum magnitude of each pulse is greater than 2500 K volts/cm.
Claim 37
Dependent Claim
12 words
A process according to claim 32, wherein said film is polyvinylidene fluoride.
Claim 38
Dependent Claim
32 words
A process according to claim 32, wherein applying said electric field having a plurality of time-spaced electric field pulses provides considerable coefficients of at least one of said pyroelectric and piezoelectric properties.
Claim 39
Dependent Claim
32 words
A process according to claim 32, wherein applying said electric field having a plurality of time-spaced electric field pulses provides substantial coefficients of at least one of said pyroelectric and piezoelectric properties.
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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) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |