Earphone

DETAILED DESCRIPTION The present invention provides an earphone including a speaker unit and a case in which the speaker unit is mounted.
The earphone of the invention is attachable to a cavity of the conha defined between the tragus of the ear and a confronting projection of the pinna and having a configuration and has a size such that the earphone will be held in this cavity by the resiliency and friction of the tragus and the confronting projection of said pinna.
The present invention also provides an earphone having a speaker unit having a vibrating diaphragm and a case in which the speaker unit is mounted.
The speaker unit is provided with a sound hole through which sound propagates, and the earphone is attachable to a cavity of a conha defined between the tragus and a confronting projection of the pinna and just in front of the auditory meatus having a configuration and a size such that the earphone will be held in the cavity by the elastic and frictional force of the tragus and the confronting projection of the pinna.
A relationship S.
sub.
1 >S.
sub.
2 >S.
sub.
3 is established, where S.
sub.
1 is the diameter or area of the vibrating diaphragm, S.
sub.
2 is the diameter or opening area of the sound hole and S.
sub.
3 is the diameter or opening area of the auditory meatus.
The invention further provides an earphone including a substantially cup-shaped outer case, sound generating means incuding a magnetic circuit and a vibraing circuit, an annular frame carrying the sound generating means, and first coupling means for coupling the outer case and the annular frame so as to form a first flush outer surface between the outer case and the annular frame.
The earphone further includes a front cover so as to form a second flush outer surface between the outer case and the annular frame.
According to another aspect of the present invention, an extension is formed from a rear side surface of the speaker case for positioning and aligning the earphone in conformance with the auditory canal, and the external cavity defined by the tragus and a confronting projection of the pinna