Speaker unit, speaker system, and speaker diaphragm manufacturing method
AssigneeJsp Corporation
InventorsYoshihisa Ishihara, Takeshi Aoki, Satoshi Iwasaki, Hirotoshi Kakuta
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Abstract
The present invention provides a speaker unit comprising a diaphragm of 0.5 to 10 mm thick aromatic polycarbonate with a density of 0.03 to 0.6 g/cm3, and a mechanism for driving the diaphragm. The aromatic polycarbonate used for the diaphragm is preferably derived from bisphenol with a viscosity average molecular weight of 25,000 to 70,000. The invention further provides a speaker system comprising such a speaker unit attached to a cabinet and a method for manufacturing the speaker diaphragm.
Claims13
A speaker unit, comprising:
- a diaphragm and a mechanism for driving the diaphragm,
- said diaphragm formed into a foam sheet or plate of aromatic polycarbonate resin having
- a 0.5 to 10 mm thickness,
- a density of 0.03 to 0.6 g/cm3,
- an elastic modulus in tension of said foam sheet or plate of at least 1 MPa at temperatures of 25° C., 50° C., 80° C. and 105° C., and
- a tan δ of said foam sheet or plate at least 0.02 at a temperature ranging from 25 to 105° C. during measurement of the dynamic viscoelasticity in bending tests giving 1 Hz frequency oscillation strain.
A method for manufacturing a speaker diaphragm, comprising the steps of:
- forming a 0.5 to 10 mm thick aromatic polycarbonate resin foam sheet or plate with a density of 0.03 to 0.6 g/cm and an elastic modulus in tension of at least 1 MPa at temperatures of 25° C., 50° C., 80° C. and 105° C., and
- a tan δ of at least 0.02 at a temperature ranging from 25 to 105° C. during measurement of the dynamic viscoelasticity in bending tests giving 1 Hz frequency oscillation strain.
Dependencies are inferred from the claim text.