Process and device for preparing a piezoelectric material
AssigneeThomson-CSF
InventorsFrancois Micheron, Jean P. Le Pesant
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Abstract
According to the invention, the dipolar orientation of an object made of material adapted to present piezoelectric properties is obtained by exposing at least one of the faces of the object to a jet of charged microparticles in order to create therein a sufficient electrical field to obtain the said orientation, and in a variant of the invention, a direct polarization is carried out by displacing a film in front of at least one generator of charged microparticles, this invention applying in particular to the production of film in a piezoelectric polymer or copolymer.
Claims17
A process for preparing a product having piezoelectric properties as a result of dipolar orientation of an object made of polar dielectric material and adapted to acquire said piezoelectric properties when the object is subjected to an electrical field of determined amplitude in order to obtain the said dipolar orientation, the electrical field being generated between two surface zones of the object which are brought to different respective electric potentials, said process further comprising exposing at least one of the said surface zones to a jet of electrically charged droplets of a first polarity, selecting the duration of said exposure so that the charged droplets are accumulated on each exposed surface zone to increase the potential difference between said surface zones up to the said determined electrical field amplitude.
Apparatus for manufacture of a product having piezoelectric properties as a result of dipolar orientation of an object having at least two opposed surfaces and made of polar dielectric material which material acquires said piezoelectric properties when subjected to an electric field of determined amplitude, said apparatus comprising:
- means for exposing at least one surface zone of a first surface of the object to a jet of electrically charged droplets of a first polarity for at least a time sufficient for the charged droplets accumulating on said surface zone to increase a potential difference between said opposed surfaces up to said determined amplitude, wherein said means includes;
- a high voltage D.C. source,
- generator means coupled to said high voltage D.C. source for emitting said charged droplets, said high voltage D.C. source charging said droplets emitted by said generator means to a first determined potential of said first polarity, said generator means located to face said surface zone, and
- conductive support means maintained at a second potential and engaged with another surface of said object.
Apparatus for manufacture of a product having piezoelectric properties as a result of dipolar orientation of an object having at least two opposed surfaces and made of polar dielectric material which material acquires said piezoelectric properties when subjected to an electric field of determined amplitude, said apparatus comprising:
- means for exposing at least one surface zone of a first surface of the object to a jet of electrically charged droplets of a first polarity for at least a time sufficient for the charged droplets accumulating on said surface zone to increase a potential difference between said opposed surfaces up to said determined amplitude, wherein said means includes;
- a high voltage D.C. source,
- generator means coupled to said high voltage D.C. source for emitting said charged droplets, said high voltage D.C. source charging said droplets emitted by said generator means to a first determined potential of said first polarity, said generator means located to face said surface zone of said first surface,
- means for bringing another surface of said object to a second determined potential, wherein
- said object has a film form and wherein said apparatus further comprises:
- first and second film storing reels, means for unwinding said film from one said reel and winding the film onto another said reel so as to displace said film intermediate said reels in a determined direction, wherein said surface zone and said means for bringing are intermediate said first and second reels.
Dependencies are inferred from the claim text.