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US 4,160,882 AGranted
Double diaphragm electrostatic transducer each diaphragm comprising two plastic sheets having different charge carrying characteristics
OwnerMichael L. Driverinventor
Life of this patent
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Abstract
An electrostatic transducer, such as a loudspeaker, employs parallel plastic diaphragms, each carrying an electrically conductive metallic layer; frames separately mounting the diaphragms, the frames assembled to a central, perforate electrically conductive sheet sandwiched between the diaphragms, and to foraminous sheets of dielectric material sandwiched between the central sheet and the diaphragms and frames, thereby to realize a compact, easily assembled unit characterized by very high performance qualities.
Claims11
In an electrostatic loudspeaker, the combination comprising
- (a) a pair of spaced, generally parallel diaphragms each of which includes a first sheet of plastic material and an electrically conductive layer adherent to said sheet,
- (b) a pair of frames respectively peripherally mounting said diaphragms, the frames extending in parallel, spaced apart relation,
- (c) a perforate, electrically conductive sheet sandwiched between said diaphragms, and
- (d) foraminous sheets of dielectric material sandwiched between said perforate sheet and said diaphragms,
- (e) whereby said diaphragms remain acoustically coupled through said foraminous dielectic sheets and through said perforate, electrically conductive sheet for simultaneous vibratory excursions when an AC signal is applied across said electrically conductive layers and said perforate sheet is connected to a common potential,
- (f) each diaphragm also including a second sheet of plastic material sandwiched between the electrically conductive layer and one of said foraminous sheets of dielectric material, said second sheet having the capacity to carry a larger permanent static charge than said first sheet, said first and second sheets consisting of different plastic materials.
3 more elements
In an electrostatic loudspeaker, the combination comprising
- (a) a pair of spaced, generally parallel diaphragms each of which includes a first sheet of plastic material and an electrically conductive layer adherent to said sheet,
- (b) a pair of frames respectively peripherally mounting said diaphragms, the frames extending in parallel, spaced apart relation,
- (c) a perforate, electrically conductive sheet sandwiched between said diaphragms, and
- (d) foraminous sheets of dielectric material sandwiched between said perforate sheet and said diaphragms,
- (e) whereby said diaphragms remain acoustically coupled through said foraminous dielectric sheets and through said perforate, electrically conductive sheet for simultaneous vibratory excursions when an AC signal is applied across said electrically conductive layers and said perforate sheet is connected to a common potential,
- (f) each diaphragm including a second sheet of plastic material sandwiched between the electrically conductive layer and one of said foraminous sheets of dielectric material, said first and second sheets peripherally wrapped about one of said frames, said second sheet is several times thicker than said first sheet,
- (g) said first sheet consisting of polyester film, and said second sheet consisting of vinylidene chloride film.
4 more elements
Dependencies are inferred from the claim text.