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Title:
ELECTROMAGNETIC DRIVER
Document Type and Number:
Japanese Patent JPS60176398
Kind Code:
A
Abstract:

PURPOSE: To improve substantially a distortion component of sound pressure reproduced by a front panel by adapting a symmetric construction in which one magnetic gap is enlarged when the other one is narrowed with respect to a vertical movement of a diaphragm.

CONSTITUTION: Two diaphragms 18a and 18b are arranged so that the equal magnetic gaps lg1 and lg2 will be formed between two opposite exciting parts, and two types of static electricity attraction force caused by permanent magnets 8a and 8b cancel out each other and turn out zero. As a result, stress to a suspension 20 totally disappears. When electrical signals are added to exciting coils 7a and 7b, magnetic force acting to the diaphragms 18a and 18b supported by the suspension 20 in the condition of zero stress through spacers 19a and 19b changes in accordance with a signal current passing in the coils, and one diaphragm acts upon static electricity attraction force to be strengthened and the other acts upon it to be weak. The difference between two types of magnetic force acts upon a front panel 3 as drive force and is reproduced as an acoustic output.


Inventors:
Saeki, Shuji
Application Number:
JP1984000031647
Publication Date:
September 10, 1985
Filing Date:
February 22, 1984
Export Citation:
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Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H04R1/00; H04R1/02; H04R1/40; H04R11/00; H04R13/00; (IPC1-7): H04R1/00; H04R1/02
Domestic Patent References:
JPS4843316A
JPS5138353U
JPS55151890A



 
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