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US 4,291,781 AGranted
Speaker diaphragm and method of preparation of the same
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHirotoshi Niguchi, Mitsuru Ieki
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AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHirotoshi Niguchi, Mitsuru Ieki
Estimating the term…
A diaphragm for a speaker which is prepared by heating a conjugated sheet obtained by paper-making polyethylene short fibers with other short fibers which have a high modulus of elasticity, such as carbon fiber, to melt and solidify polyethylene short fibers in the conjugated sheet; the process for the production thereof. The diaphragm for a speaker of the invention has a high modulus of elasticity and a high internal loss and a speaker prepared with such a diaphragm has the advantage of having a wider reproducing frequency response and lower distortion. Furthermore, the process for production of the invention possesses another advantage in that diaphragms for speakers can be produced in a continuous process of successively pressing out the speaker diaphragm with a cold mold press.
A diaphragm for a speaker, comprising a sheet, paper-made of polyethylene short fibres being present in an amount of 70% by weight or more, said polyethylene short fibers having a degree of beating of 250 ml (Canadian Freeness), a melt index of not more than 2 g/min. and being not more than 1 millimeter in length and other short fibres between 3 and 10 millimeters in length which have a modulus of elasticity of at least 1.1.times.10.sup.10 dyne/cm.sup.2, said polyethylene short fibers being melted to bond with said other short fibres in said sheet;
A diaphragm for a speaker, comprising laminated plural sheets, paper-made of polyethylene short fibres being present in an amount of 70% by weight or more, said polyethylene short fibers having a degree of beating of 250 ml (Canadian Freeness), a melt index of not more than 2 g/min. and being not more than 1 millimeter in length and other short fibres between 3 and 10 millimeters in length which have a modulus of elasticity of at least 1.1.times.10.sup.10 dyne/cm.sup.2, said polyethylene short fibres being melted to bond with said other short fibres in said sheets;
A diaphragm for a speaker comprising sheets, paper-made of polyethylene short fibres being present in an amount of 70% by weight or more, said polyethylene short fibers having a degree of beating of 250 ml (Canadian Freeness), a melt index of not more than 2 g/min. and being not more than 1 millimeter in length and other short fibres between 3 and 10 millimeters in length which have a modulus of elasticity of at least 1.1.times.10.sup.10 dyne/cm.sup.2, said polyethylene short fibers being melted to bond with said other short fibres in said sheets;
Dependencies are inferred from the claim text.