An earphone comprising a housing formed on the outer periphery of the front face with a flange for preventing the housing from disengagement from the concha when the housing is received in a recess of the concha, said housing being sized to be received in the recess of the concha and having an electroacaustic transducer built in.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an earphone, and more particularly to a very 
compact and light earphone which can be used comfortably and attached to 
the ear securely. 
2. Description of the Prior Art 
Conventional earphones used for the appreciation of music or the like are 
known such as for example, air tight magnetic type earphones and the 
so-called dynamic type earphones. 
In magnetic type earphones, an iron piece is disposed in front of a coil 
and yoke constituting a magnet circuit so as to vibrate the iron piece, 
and a vinyl tube is attached to a projection having a vent hole which is 
formed in front of the iron piece and which is inserted into the interior 
of the external auditory meatus (canal) of a wearer. In this type of 
earphone, however, since the vinyl tube has to be inserted into the 
interior of the external auditory meatus, it causes discomfort and often 
becomes covered with sweat. Also, since the vinyl tube supports the 
earphone to prevent it from disengagement from the concha, the iron piece 
which is a vibrative member is located remotely from the eardrum so that 
satisfactory high fidelity sounds can not advantageously obtained. 
Also, in dynamic type earphones, a diaphragm is vibrated in a magnetic 
circuit formed of a voice coil, a yoke, a magnet and a plate. This type of 
earphone, has a projection having a vent hole formed in front of a 
diaphragm and an attachment formed of urethane or the like which is 
attached to the projection which is to be inserted into the interior of 
the external auditory meatus of a user during use and it inevitably causes 
physical discomfort. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a compact and light earphone. 
Another object of this invention is to provide an earphone which is 
provided with a housing which is received in a recess of the concha and a 
transducer which is received in the housing and is suitable for 
reproducing high fidelity sounds. 
Still another object of this invention is to provide an earphone which is 
provided with a housing having a built in transducer built and a flange 
formed on the housing for engaging projections of the concha to prevent 
the earphone from disengagement from the concha when the housing is 
received in a recess of the concha. 
A further object of this invention is to provide an earphone in which a 
transducer is provided in a housing attached to the concha and the 
diameter of the diaphragm in the transducer is substantially equal to that 
of the housing so that the diaphragm is located sufficiently close to the 
eardrum for transmitting satisfactory the reproduced sounds. 
A still further object of this invention is to provide an earphone in which 
an earphone body is provided with a clip which clips to a portion of the 
concha so as not to disengage the earphone body from the concha even when 
the user wears the earphone while doing strenuous exercises. 
A yet further object of this invention is to provide an earphone comprising 
a housing formed so as to be received in a recess of the concha, a 
magnetic circuit received in said housing, a diaphragm magnetically 
coupled to said magnetic circuit and a flange formed around said housing 
for engaging projections of the concha when said housing is received in 
the concha.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in FIG. 1, an earphone 20 according to this invention is formed of 
an electroacaustic transducer 23 formed of a vibrating portion 21 and a 
magnetic circuit 22 and a housing 24 in which the transducer 23 is 
mounted. Said vibrating portion 21 is formed of a diaphragm 25 having a 
sufficiently large effective area for reproduction of satisfactory sound. 
A voice coil 26 is wound around the outer periphery of the annular portion 
of the diaphragm 25 and an edge 27 is provided for supporting said 
diaphragm in place. The diameter of said diaphragm 25 is substantially 
equal to that of the housing 24. Also, the magnetic circuit 22 is formed 
of an annular magnet 28 formed of rare earth cobalt system magnets such as 
samarium cobalt magnets which have excellent magnetic performance and a 
yoke 29 for guiding the magnetic flux generated by the magnet to a 
magnetic cavity and forming magnetic poles. Further, in the housing 24 are 
built the respective parts of said vibrating portion 21, the magnetic 
circuit 22 and other parts. The housing 24 has formed on the outer 
periphery of its front face an annular flange 30 which projects outwardly. 
As shown in FIGS. 2 and 3, flange 30 is located at the inlet of the 
external auditory meatus (canal) 31 where it engages the cartilaginous 
lugs 33a located at predetermined positions of the outer periphery of a 
recess 33 in the central portion of the shell-like concha 32 which 
surrounds the external auditory meatus 31 so as to prevent the earphone 20 
from undesired disengagement from the concha after the housing 24 is 
received in said recess 33. Further, the flange 30 is formed to have an 
outer diameter with a dimension l.sub.1 of about 1.8 cm, for example. 
This flange 30 has formed on its outer periphery an annular bent-up portion 
34 which receives inside a ring 36 which supports said edge 27 and 
supports the outer periphery 35a of a protector 35 which is mounted in 
front of the diaphragm 25 and which is attached to the bent-up portion 34. 
Said protector 35 is formed with a plurality of vent hles 37, 37 . . . . 
Further the front face of this protector 35 may be covered with a 
material, for example urethane, which is can be to be penetrated by sound. 
Further, in this embodiment, the thickness l.sub.2 of the bent-up portion 
34 formed on the flange 30 is about 1.5 mm so that it can be 
satisfactorily received in the recess 33 in the concha 32. 
A terminal board 39 is connected to one end of a cord and is integrally 
fixed to the back of said housing 24 with a mold portion 40 or the like 
formed of synthetic resin. This terminal board 39, mold portion 40, pole 
41, magnet 28 and yoke 29 are respectively formed in their central 
portions with a through hole 42 so that the inside and outside of the 
housing 24 communicate with each other. Thus, the back of the housing 24 
is opened to the outside space which provides desirable tonal quality. 
Also, the mold portion 40 effects a buffer action on the cartilaginous 
lugs 33a of the concha so as not to produce pain when the earphone 20 is 
attached to the concha. 
Further, the flange 30 is formed along the outer periphery of the housing 
24 with a plurality of vent holes 30a. 
Next, there will be described a method of using this invention. As shown in 
FIG. 3, the earphone 20 according to this invention is received in the 
recess 33 of the concha 32 such that the protector 35 side is directed 
towards the external auditory meatus 31 of the concha 32. Since the 
earphone 20 according to this invention uses a samarium cobalt magnet or 
the like for the magnet 28 provides a compact and light earphone and, it 
can be easily received in the recess 33 of the concha 32. 
Also, since the earphone 20 according to this invention is received in the 
inlet of the external auditory meatus 31 of the concha 32, the diaphragm 
25 can be located close to the eardrum. Since a samarium cobalt magnet or 
the like is used for the magnet 28 it forms a sufficiently large effective 
area for the diaphragm 25 so that the range can be expanded and high 
fidelity sounds will be obtained. 
Further in the earphone 20 according to this invention, since only a 
portion of the earphone 20, such as the outer periphery of the protector 
35, engages the concha 32, the earphone will not become covered with sweat 
or produce pain and it can be used for a long time without discomfort. 
FIG. 4 shows an example of an attachment to more securely attach said 
earphone to the concha. 
In this example, the housing 24 of the earphone 20 shown in FIG. 1 is 
provided with a string or cord member 50 having a pair of sandwiching 
pieces 51, 51 which form a clip. A pair of sandwiching pieces 51, 51 are 
interconnected with a connecting flexible string 52 and are respectively 
formed of magnetic material. At least one of these pieces is formed of a 
permanent magnet material, as for example rare, earth cobalt permanent 
magnet material such as samarium cobalt magnet material which has very 
high magnetic attraction. 
The other piece of the sandwiching pieces 51, 51 may be formed of magnetic 
material such as iron. However, both pieces 51, 51 are preferably formed 
of permanent magnetic material to adequately support the earphone 20. 
As shown in FIG. 4, said pair of sandwiching pieces 51, 51 sandwich both 
sides of the concha 32 after the earphone 20 is received in the recess 33 
of the concha 31 such that the protector 35 side is directed towards the 
external auditory meatus 31 side of the concha 32. Since magnets having 
very high magnetic attraction, for example, samarium cobalt magnet, are 
used for the sandwiching pieces 51, 51, the pieces 51, 51 will be firmly 
secured to the concha 32. Accordingly the earphone 20 is firmly secured to 
the concha 32 with these sandwiching pieces so that said earphone 20 can 
not be disengaged from the concha 32 even when a wearer listens to music 
while performing strenuous exercises. 
Further, while in the above-mentioned embodiment a pair of sandwiching 
pieces 51, 51 sandwich the upper portion of the concha, a pair of 
sandwiching pieces provided on the cord 38 may sandwich the lower portion 
of the concha. 
As is apparent from the above description, the earphone according to this 
invention is sufficiently compact and light for being received in the 
recess of the concha so that it can be securely attached to the concha and 
used for a long time and it will provide high fidelity sound since the 
diaphragm can be located sufficiently close to the eardrum. 
Also, since the earphone according to this invention is provided on the 
outer periphery of the front face of the cabinet with the flange, the 
earphone cannot be accidentally disengagement from the concha. 
Further, the earphone according to this invention is provided with a pair 
of sandwiching pieces so that the earphone will be prevented from 
disengagement from the concha even when a wearer performs strenuous 
exercise with earphone in the concha. 
Further, while in the above embodiment of this invention so-called dynamic 
type earphone is described, this invention can be applied also to an 
electromagnetic earphone or the like for example.