JPH0424720Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (industrial field of application) This invention is designed to enable hearing-impaired people who use hearing aids with pick-up coils held near the ear to This invention relates to a receiver unit that allows you to make calls by applying it to a pick-up coil in the same way as a person. This unit is incorporated into a handset to form the handset.

(Prior art) Older hearing aids used by hearing-impaired people include a case that houses the main components such as a microphone, amplifier, and battery, and is inserted into the ear canal or placed near the ear canal using glasses. The earphones held were connected to the main body with long conductive wires, and the audio current obtained by the microphone was amplified and heard by the receiver.

However, this type of hearing aid is extremely inconvenient when used with a telephone handset in which the transmitter and receiver are fixed at a short distance apart. That is,
When making a call, you must hold the transmitting part of the handset close to your mouth, and when receiving a call, you must place the receiving part against the main part of the hearing aid in your breast pocket, so you do not have to move the handset frequently. No.

In order to eliminate this inconvenience, in recent years, the main part has been manufactured in a small size and is hung on the ear, and a pick-up coil is installed inside the main part to capture the leakage magnetic flux of the signal current coming from the receiver part of the handset and to generate voice current. More and more types of hearing aids have come into use.

As shown in FIG. 3, this hearing aid with a pick-up coil (A in FIG. 3) is equipped with a pick-up coil 2 separate from the microphone 1, and a voice for driving a diaphragm in the receiving section B of the handset of the telephone. When an audio current enters the coil 3 from the terminal 4, the current obtained by capturing the leakage magnetic flux of the coil 3 is amplified by the amplifier 5 together with the audio current obtained by the microphone, and the earphone 6 is inserted to generate sound and put into the ear. It is something.

As a receiver unit that is built into a general handset and receiver to create a receiver, as shown in Figures 5 and 6,
A magnetic circuit is formed by sandwiching an annular permanent magnet 7 between a yoke 8 and a yoke 10 having a center pole 9, and the magnet 7 and yokes 8 and 10 are combined with a synthetic resin holder 12 during molding, and the center pole 9 and When using a moving coil type unit in which the voice coil 3 fixed to the diaphragm 11 is inserted between the yoke 8 and the yoke 8, due to magnetic leakage of the magnet 7, the clip on the desk or the pin holding the hair on the receiver may This causes inconveniences such as being attracted to the telephone, and the leaked magnetism affecting a special switch installed in the telephone body. Therefore, as shown in FIG. 5, the outer surface of the unit 12 is covered with a shield case 13 made of a magnetic material such as an iron plate. 14 is a spacer, 15
is a hole through which sound waves pass.

On the other hand, in order to make it easier for hearing aid users to listen to telephone calls, it has become common practice to provide a field coil 16 in addition to the voice coil 3 in the unit, as shown in FIGS. 1 and 3. It's here. Although FIG. 3 shows the field coil 16 provided in parallel with the voice coil 3, it may also be provided in series.

(Problem to be Solved by the Invention) However, if the receiver unit is covered with the shield case 13 in order to prevent the magnetic flux leakage from the magnet 7, which has the above-mentioned disadvantage, the magnetic flux emitted from the field coil 16 will flow into the pickup coil 2. This also prevents the field coil 16 from reaching the target, and the benefit of providing the field coil 16 is lost.

B. Structure of the invention (Means for solving the problems) This invention is designed to provide a shielding case that allows the AC magnetic flux generated by the sound current emitted from the field coil 16 to pass through the shielding case 16 and reach the pickup coil 2. A hole is provided at a position facing the 13 field coils 16.

(Function) The shield case 13 prevents the magnetic flux of the permanent magnet 7 from leaking, and at the same time prevents the field coil 1 from leaking.
This also prevents the magnetic flux emitted from the field coil 16 from going outside the receiver unit, but since a hole is provided in the front part of the field coil, most of the magnetic flux emitted from the field coil 16 is allowed to go out and act on the pickup coil 2 of the hearing aid. This can enhance the sound that a hearing aid user hears.

(Embodiment) Figures 1 and 2 show an embodiment of the receiver unit of the present invention. The same reference numerals will be used for the same parts as those of the conventional example shown in FIGS. 5 and 6, and this will be explained below.

A ring-shaped permanent magnet 7 is connected to a yoke 8 and a center pole 9.
It is the same as the conventional one shown in FIG. 5 in that it is held between two yokes 10 with a yoke 10 and held by a holder 12 made of synthetic resin, and that a voice coil 3 and a diaphragm 11 are provided. Front side of holder 12 (right side in the figure)
A part of the field coil 16 is inserted into the groove formed in the groove, and the other part of the field coil 16 is fitted into the groove of the synthetic resin spacer plate 17, and the field coil 16 is inserted between the holder 12 and the spacer plate 17. The holding body 12 and the spacer plate 17 are covered with a shield case 13. A hole 18 is provided in the center of the front surface of the shield case 13, and within this hole 18, a hole 15 through which sound passes is provided in the spacer plate 17. Further, the shield case 13 is provided with an arc-shaped hole 19 in front of the field coil 16.

When audio current enters the receiver unit from terminal 4, voice coil 3 and field coil 16
This current flows to generate magnetic flux. The magnetic flux emitted by the voice coil 3 interacts with the magnetic flux of the magnet 7 to drive the diaphragm 11 and generate sound waves, and some of the magnetic flux emitted by the field coil 16 is captured by the shield case 13, but the rest is captured by the hole 19. The sound waves exit from the front through the earphones 6 and act on the pickup coil 2 of the hearing aid to enhance the sound waves emitted from the earphones 6. Most of the leakage magnetic flux of the magnet 7 is captured by the shield case 13.

The inventor of the present invention found that the leakage flux of the permanent magnet 7 was attenuated by about 69% in the conventional receiver unit shown in FIGS. In the case of the present invention shown in Figs. 1 and 2, the attenuation of leakage magnetic flux was about 58%.

Furthermore, the state in which the magnetic flux emitted from the field coil 16 is blocked by the shield case 13 is attenuated by about 50% in the conventional case shown in FIGS. The attenuation stopped at 13%.

That is, according to the structure of the present invention, the effect of blocking the leakage magnetic flux of the permanent magnet 7 is about 10% lower than that of the conventional structure, but the effect of passing the magnetic flux produced by the field coil is large.

C. Effects of the invention (1) By providing the hole 19 in the shield case 13, much of the magnetic flux emitted by the field coil 16 can reach the pickup coil.

(2) Even if the hole 19 is provided, the effect of blocking the leakage magnetic flux of the permanent magnet 7 is only slightly reduced, which is of no practical problem, and the inconvenience of attracting small magnetic objects can be almost completely prevented.

(3) If this receiver unit is incorporated into the receiver of a telephone handset, telephone use by hearing aid users can be greatly facilitated.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view of the receiver unit of the present invention, Fig. 2 is a front view seen from the right side of Fig. 1, and Fig. 3 is a longitudinal side view of the receiver unit of the present invention.
The figure shows a connection diagram of a hearing aid with a pickup coil equipped with a field coil and a receiver unit, Figure 4 is a connection diagram of a conventional hearing aid with a pickup coil without a field coil, and Figure 5 shows a receiver unit with a conventional shield case. FIG. 6 is a longitudinal sectional side view of the unit, and FIG. 6 is a front view seen from the right side of FIG. 1...Microphone, 2...Pick-up coil, 3...Voice coil, 4...Terminal, 5...Amplifier, 6...Earphone, 7...Permanent magnet, 8...
... Yoke, 9 ... Center pole, 10 ... Yoke, 11 ... Vibration plate, 12 ... Holder, 13 ...
Shield case, 14... Spacer, 15...
Hole, 16... Field coil, 17... Spacer plate, 18, 19... Hole.

Claims (1)

[Scope of utility model registration request] This receiver unit is a moving coil type receiver unit provided with a field coil 16 and whose outer surface is covered with a magnetic shield case 13, in which a hole 19 for passing the magnetic flux of the field coil is provided in a part of the shield case 13 facing the field coil 16.