JPS5828800B2 - Electrostatic headphone device - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in electrostatic headphone devices.

As is well known, an electrostatic headphone device is constructed by installing an electret fixed electrode in close opposition to a diaphragm, applying an alternating current voltage between the diaphragm and the fixed electrode, and absorbing the vibrations generated at this time. It uses the vibration of the plate.

Here, if the gap between the diaphragm and the fixed electrode is d1, the electret voltage is Vo, and the AC voltage is V, then the electric field strength E between the diaphragm and the fixed electrode is given by:

If there is air between the diaphragm and the fixed electrode, when the electric field strength E exceeds approximately 106 [■/m], a discharge phenomenon occurs due to air destruction, which causes the problem that the voltage of the electret decreases. Ta.

Therefore, conventionally, in order to prevent the above-mentioned discharge phenomenon, a varistor has been inserted into a part of the adapter interposed in the headphone cord.

Incidentally, headphones are required to have high sensitivity and high performance, and to have a configuration that does not give the user a sense of discomfort.

Especially considering the latter point, having a part of the adapter interposed in the headphone cord as described above will not only make the user feel uncomfortable while wearing the headphones, but also be inconvenient when putting on and taking off the headphones. It was something.

Therefore, there is a strong desire to develop headphones that can eliminate a portion of the adapter and also prevent the above-mentioned discharge.

This invention was made based on the above circumstances, and an object of the present invention is to provide an extremely good electrostatic headphone device that can be easily put on and taken off without causing any discomfort to the user while being worn, and can also prevent discharge phenomena. shall be.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, 11 is a casing having a substantially bottomed cylindrical shape;
A sound emitting portion 14 having a plurality of through holes 13 is formed approximately at the center of the eave-like flat portion 12.

A ring-shaped ear pad 15 is provided on the outer wall of the eave-shaped flat part 12 of the casing 11 so as to surround the sound emitting part 14.
is attached.

In addition, on the inner wall of the eave-like flat part 12 of the casing 11,
An electro-acoustic conversion unit 16 is attached so as to face the sound emitting section 14.

As shown in FIG. 2, this electro-acoustic conversion unit 16 is connected to a fixing ring 18 made of a conductive material on which a diaphragm 17 is stretched, with a substantially ring-shaped spacer 19 made of an insulating material interposed therebetween. , a fixed electrode 21 made of an electret and having a plurality of through holes 20 is brought into contact with the fixed electrode 21 .

A retaining ring 22 made of a conductive material is brought into contact with the back side of the fixed electrode 21.

Here, the fixing ring 18 and the retaining ring 22 include:
A pair of substantially protruding connection electrodes 181, 182 and 2, respectively.
21.222 are formed.

Then, as shown in FIG. 1 again, the electro-acoustic conversion unit 16 has its fixing ring 18 brought into contact with the inner wall of the eave-like flat part 12 of the casing 11. Connection electrodes 181 and 221 of the fixing ring 18 and the retaining ring 22 are formed protruding from the inner wall and have a locking part 23.24 at the tip, and have a base and a tip.
and through holes 25 and 26 that fit with 182°222, respectively.
It is attached by a pair of support parts 29 and 30 formed with angles of 27° and 28.

Further, a thread groove 31 is provided at the open end of the casing 11.
is formed, and the headphone housing 33 is completed by screwing the cover body 32 into the thread groove 31.

A recess 34 is formed approximately at the center of the lid 32, and a transformer 35 is accommodated within the recess 34.

As shown in FIG. 2, connection electrodes 182 and 222 of one of the fixing ring 18 and the retaining ring 22 are connected to both ends of the secondary winding 352 of the transformer 35, respectively.

Further, both ends of the primary winding 351 of the transformer 35 are connected to a signal source (not shown) via connection terminals 36 and 37, respectively.

At this time, as shown in FIG. They are grouped together by a cord 40 and connected to the signal source.

Furthermore, a capacitor 41 for preventing discharge is connected within the casing 11 between the other connecting electrodes 181 and 221 of the fixing ring 18 and the retaining ring 22.

Note that on the back side of the lid 32, there is a connector 4 (not shown) that connects the headband and the headphone housing 33.
2 is attached.

Then, the signal voltage from the signal source is stepped up by the transformer and supplied to the fixing ring 18 and the retaining ring 22, thereby causing the diaphragm 17 to vibrate as described above, where electrical-acoustic conversion occurs. is to be done.

At this time, even if the electric field strength E between the diaphragm 17 and the fixed electrode 21 exceeds 106 (V/m, 1), the action of the discharge prevention capacitor 41 prevents the occurrence of the discharge phenomenon. can.

In addition, since the transformer 35 and capacitor 41 are provided inside the headphone housing 33, there is no need to interpose a part of the adapter in the headphone cord as in the conventional case, and the user can easily put on and take off the headphone without feeling uncomfortable when wearing it. This can be done easily.

Here, the capacitor 41 for preventing discharge may be connected as shown in FIG.

That is, one support portion 2 formed in the casing 11
Through holes 291 and 292 are formed in 9, and the through holes 291°29
The lead legs 411, 412 of the capacitor 41 are inserted through the capacitor 2, and the capacitors 41 and 412 are sandwiched and connected between the fixed electrode 21 and the retaining ring 22, and between the diaphragm 17 and the spacer 19, respectively.

In this way, the capacitor 41 can be easily connected, and the assembly work efficiency can be improved.

Here, the electro-acoustic conversion unit used in the above headphones was of a so-called single type in which one fixed electrode was placed in contact with a diaphragm.
As shown in the figure, it may be configured as a push-pull type.

That is, a diaphragm 44 is stretched around a fixed ring 43 made of a conductive material, and fixed electrodes 45 and 46 with holes are provided in opposing positions above and below the diaphragm 44 in the figure.

Holding rings 47, 48 made of a conductive material are abutted on the perforated fixed electrodes 45, 46, respectively.

A signal source 49 and a capacitor 50 for preventing discharge are connected between the fixing ring 43 and the retaining ring 47, and both retaining rings 47 and 48 are short-circuited.

In this way, the diaphragm 44 has two fixed electrodes 45.
46, it is driven in a push-pull manner.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

Therefore, as detailed above, according to the present invention, it is possible to provide an extremely good electrostatic headphone device that can be easily put on and taken off without causing any discomfort to the user while being worn, and can also prevent discharge phenomena. can.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of an electrostatic headphone device according to the present invention, FIG. 2 is an exploded perspective view showing the structure of the diaphragm and fixed electrode portion of the same embodiment, and FIGS. FIG. 4 is a side sectional view showing a modification of the same embodiment. 11...Casing, 12...Eave-shaped flat part, 13...Through hole, 14...Sound emitting part, 15...Ear pad , 16... Electric-acoustic conversion unit, 17... Vibration plate, 18...
...Fixing ring, 19...Spacer, 2
0...Through hole, 21...Fixed electrode, 22
...Retaining ring, 23, 24...Locking portion, 25 to 28...Through hole, 29, 30...
...Support part, 31...Thread groove, 32...
・・・1L33・・・Hesodohonno Uzingu, 3
4... recess, 35... transformer, 36.
37...Connection terminal, 38, 39...Lead wire, 40...Headphone cord, 41...
... Capacitor, 42 ... Connector, 43.
...Fixing ring, 44...Diaphragm, 45
゜46... Perforated fixed electrode, 47, 48...
...Retaining ring, 49...Signal source, 50...
...Capacitor.

Claims (1)

[Claims] 1. A diaphragm, a fixed electrode that is in contact with the diaphragm, a transformer that boosts and supplies electrical signals to the diaphragm and the fixed electrode, and a discharge that is inserted and connected between the diaphragm and the fixed electrode. An electrostatic headphone device characterized in that a capacitor for prevention is housed in a headphone housing.