JPH11289365A - Portable communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a portable communication terminal which is easily miniaturized and is advantageous for cost reduction as well. SOLUTION: This portable communication terminal is constituted by providing an ear flap part 15 against which a user's is put on a housing 11 and fixing a piezoelectric vibrating body 12 on the inside wall of other wall part to face opposite to a wall part on which the ear flap part 15 on the housing 11 is provided. More specifically, the piezoelectric vibrating body 12 is installed on the inside wall of a part, where a battery 18 of the housing 11 is attachably/ detachably installed. A sound emitting hole 16 is provided on the ear flap part 15 on the housing 11 and is provided with a braking function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable communication terminal such as a portable telephone or a handset capable of making a call without a cord by an indoor radio, and more particularly, to a portable communication terminal having a housing provided with an earrest for a user to listen to. The present invention also relates to a portable communication terminal having a piezoelectric vibrating body attached to the housing.

[0002]

2. Description of the Related Art A piezoelectric acoustic device having a structure as shown in FIGS. 3 and 4, for example, has been mainly used as a receiver of a conventional portable communication terminal device. The piezoelectric element 6 is formed by forming a piezoelectric film 8 on one surface of a vibration plate 7 and soldering lead wires 9 and 10 to the vibration plate 7 and electrodes provided on the surface of the piezoelectric film 8, respectively. The piezoelectric element 6 is housed in a tray-shaped case 1 having a step 2 in the middle of the inner peripheral surface, and the periphery of the diaphragm 7 is supported by the step 2 and a silicone adhesive 5 (see FIG. 4). ) Or the like. The lead wires 9 and 10 are drawn out of the case 1 from the recess formed in the peripheral wall of the case 1, and the hermeticity of the recess is ensured.

Further, a damper is provided on the upper wall of the case 1 to adjust the sound pressure-frequency characteristics of the sound generated from the piezoelectric acoustic device. For example, when a piezoelectric element 6 having a diameter of about 20φ is used, a through hole 3 having a diameter of about 1 to 2φ is provided in the center of the upper surface of the case 1, and a mesh 4 of about # 380 made of Tetron or the like is provided to form a damper. I have. With this damper, the sound pressure-frequency characteristic is adjusted so that a required sound pressure level is obtained in a predetermined sound range. other,
There is a case where a large number of small holes are opened without using the mesh 4 as described above, and the small holes are used as dampers.

Such a piezoelectric acoustic device is attached to a portable communication terminal such as a portable telephone or a receiver as shown in FIG. That is, the case 1 containing the piezoelectric element 6 is applied with the opening side of the case 1 facing the inner surface of the housing 31 of a sounding device such as a mobile phone or a cordless horn. It is fixed with a double-sided adhesive sheet or the like via a gasket made of an elastic material such as. Further, the lead wires 9, 10 are connected to the housing 31.
It is connected to a printed circuit board (not shown) housed inside, and is connected to the circuit of the portable communication terminal.

[0005]

In the above-described piezoelectric acoustic device, a piezoelectric element 6 in which a piezoelectric film 8 is formed on one side of a vibration plate 7 is housed in a case 1, and this case 1 is further mounted on a cellular phone, a cordless phone or the like. Needs to be attached to the housing 31 of the portable communication terminal. Therefore, case 11
It is difficult to miniaturize. Also, since the number of parts is large, the production cost of the parts is high. In particular, the case 1 is a molded plastic article, and the incineration cost for the mold cost is large. Moreover, since the assembly is complicated, the number of assembly steps is large. Therefore, the portable communication terminal incorporating the piezoelectric acoustic device as described above has a problem that it is difficult to reduce the size and the manufacturing cost. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of a conventional portable communication terminal using a piezoelectric acoustic device, and has as its object to provide a portable communication terminal that can be easily downsized and that is advantageous in cost reduction. .

[0006]

According to the present invention, in order to achieve the above object, a piezoelectric vibrator 12 is used as a sound source, and the piezoelectric vibrator 12 is fixed to an inner wall of a housing 11 of a portable communication terminal. It was done. Thereby, the housing 11 of the portable communication terminal itself can be used as an acoustic box, and a portable communication terminal capable of obtaining a higher sound pressure level by the piezoelectric vibrator 12 can be obtained. And
Ear cover 1 for the user to touch the outer wall of housing 11
5 is provided, and the piezoelectric vibrating body 12 is fixed to the inner wall of the other wall opposite to the wall on which the earpiece 15 is provided, so that vibration is suppressed by a human ear or the like applied to the earpiece 15. Instead, it allows stable pronunciation.

That is, in the portable communication terminal according to the present invention, an ear cover portion 15 for applying a user's ear to the outer wall of the housing 11 is provided, and the piezoelectric vibrator 12 is fixed to the inner wall of the housing (11). It is characterized by the following. In particular, as a mounting portion of the piezoelectric vibrating body 12, the piezoelectric vibrating body 12 is fixed to the inner wall of the other wall of the housing 11 opposite to the wall on which the ear rest 15 is provided. Specific locations for attaching the piezoelectric vibrating body 12 include an inner wall of a wall of the housing 11 to which the battery 18 is detachably attached and a position facing the earpiece 15 of the housing 11.

The piezoelectric vibrating body 12 is an element which is provided with an electrode facing the piezoelectric body and performs a mechanical movement by a piezoelectric strain generated when a voltage is applied between the electrodes. By fixing such a piezoelectric vibrating body 12 to the inner surface of the housing 11 of the portable communication terminal, the housing 11 of the portable communication terminal itself can be used as an acoustic box to emit sound. Further, when the portable communication terminal is used, for example, the ear of the user of the portable communication terminal may come into contact with the ear pad 15, and the vibration of that portion may be suppressed. In this regard, in the portable communication terminal, the piezoelectric vibrating member 1 is fixed to the inner wall of the other wall portion of the housing 11 opposite to the wall portion on which the ear covering portion 15 is provided.
2, stable sound generation is possible without hindering the vibrations caused by the vibrations of the second and third modes. Further, by providing the sound emission hole 16 in the ear cover 15 of the housing 11, sound can be transmitted efficiently. Furthermore, since the sound emission hole 16 has a braking function, it is possible to adjust the frequency-sound pressure level.

[0009]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings.
FIG. 1 is a partially longitudinal side view showing an example of a portable communication terminal according to the present invention. In FIG. 1, the left side is an upper side and the lower side is a front side.

[0010] The housing 11 is formed of a resin molded body, and is provided with an antenna 13 at an upper portion thereof, which can be pulled out upward. Housing 11
A circuit board 20 provided with a display unit such as a liquid crystal display is built in the inside, and the circuit board 20 constitutes an electronic circuit required as a portable communication terminal. At a position near the upper end of the front surface of the housing 11, there is provided a see-through window 14 through which the display unit such as a liquid crystal display for visually displaying necessary information by the electronic circuit can be seen. Below the see-through window 14, a key switch 17 is provided for a user to input operation information and the like necessary for the electronic circuit. Below the key switch 17, a microphone 19 for converting a user's voice into an electric signal is provided. The microphone 19 obtains sound from outside the housing 11 and converts the sound into an electronic signal. This microphone 19 is connected to the housing 1
The interior space of the housing 11 is soundproofed so as not to receive the sound inside the housing 1. Above the front wall of the housing 11, an earpiece 15 is provided for the user to listen to a sound by putting his / her ear, and in the illustrated example, the earpiece 15 is provided with a sound emission hole 16. It is preferable that the sound output hole 16 has a braking function by stretching a braking cloth or the like for adjusting acoustic characteristics. Further, a waterproof sheet or a dust-proof sheet may be attached. A battery 18 for driving a circuit formed on the circuit board 20 is detachably attached to the lower rear of the housing 11. In FIG. 1, a solid line indicates a state where the battery 18 is mounted, and a two-dot chain line indicates a state where the battery 18 is removed. The state is shown. It is preferable that both the inner wall and the outer wall of the lower part of the rear surface of the housing 11 to which the battery 18 is attached are flat.

In the example shown in FIG. 1, the piezoelectric vibrator 1 is mounted on a flat inner wall below the back of the housing 11 to which the battery 18 is mounted.
2 is fixed. The inner wall portion below the back surface of the housing 11 to which the battery 18 is attached is the widest flat portion of the housing 11, and a relatively large piezoelectric vibrator 12 can be attached here.

The piezoelectric vibrating body 12 is an element which is provided with an electrode facing the piezoelectric body and performs a mechanical movement by a piezoelectric strain generated when a voltage is applied between the electrodes. Piezoelectric vibrators include a linear displacement type using in-plane displacement, that is, deformation in a plane direction, and a bending displacement type using out-of-plane displacement, that is, bending that is displacement in a direction perpendicular to the plane. In the former,
There are a single-plate type made up of a single-layered piezoelectric body and a laminated type made up of a plurality of piezoelectric bodies. The latter include a monomorph type consisting of a single-layer piezoelectric body, a unimorph type combining a piezoelectric body and an elastic plate one by one, a bimorph type sandwiching an elastic plate between two piezoelectric bodies or two piezoelectric bodies, There is a multimorph type in which a piezoelectric body is bonded. In the present invention, any type of piezoelectric vibrator can be applied, but when a particularly high sound pressure level is required, a piezoelectric vibrator such as a laminated type, a bimorph type, or a multimorph type capable of obtaining a large displacement output is used. used. The opposing electrodes of the piezoelectric vibrator 12 are connected to a drive circuit formed on the circuit board 20. Piezoelectric vibrator 1
2 has an extremely fast response speed, so that it can vibrate and emit sound by applying a sound signal.

The piezoelectric vibrator 12 is mounted on the inner surface of the housing 12.
Can be fixed by any means such as bonding with an adhesive or bonding via a double-sided adhesive sheet. Thus, the vibration of the piezoelectric vibrating body 12 is transmitted to the housing 11, resonates inside the housing 11, and the sound is emitted from all surfaces of the housing 11. However, in order to block surrounding sounds and improve audibility, it is preferable to provide the earpiece 15 to which the user's ear is attached. By appropriately selecting the thickness of the entire housing 11, particularly the thickness of the earpiece 15, the size and shape of the sound emission hole 16, the presence or absence of a braking cloth, and the like, the sound is released from the earpiece 15 to the outside of the housing 11. The frequency-sound pressure level characteristics of the sound can be adjusted to be appropriate. Specifically, 300Hz ~
Adjust so that the 3.4 KHz sound is emitted at a flat sound pressure level. When the sound emitting hole 16 is provided in the earpiece portion 15, the frequency-sound pressure level characteristics can be easily adjusted as described above. On the other hand, when the sound emitting hole 16 is not provided, the waterproofness becomes high. There are advantages.

When the earpiece 15 is used as an earphone with the user's ear in contact with the earpiece 15, the piezoelectric vibrating body 1 is used so that the sound pressure level of the sound emitted from the earpiece 15 is not excessive.
2 is controlled. In addition, since a piezoelectric vibrator capable of obtaining a large displacement output is used, by changing the conditions for applying voltage to the piezoelectric vibrator 12, the piezoelectric vibrator can be used as a speaker for listening to sound while the ear is away from the earpiece 15. Is also possible.

As described above, the microphone 19 is
Since the sound is prevented from receiving the sound inside the housing 11, the sound generated by the vibration of the piezoelectric vibrating body 12 is not received. As described above, the piezoelectric vibrator 1
2 is attached to the rear side of the housing 11,
Even when the user of the portable communication terminal touches the ear cover 15 of the housing 11 with the ear or the like, the piezoelectric vibrating body 12 can vibrate without being affected and generate sound. In particular, the part to which the battery 18 is attached has a double wall formed by the relatively thick battery 18 in addition to the wall of the housing 11 in a normal use state. Almost no influence, stable vibration and sound can be generated in all use conditions.

FIG. 2 is a partially longitudinal side view showing another example of the portable communication terminal according to the present invention. In this example, the piezoelectric vibrating body 12 is attached to the inner wall on the back surface of the housing 11 opposite to the front surface portion where the ear cover 15 is provided.
This position is narrower than the inner surface of the portion where the battery 18 is attached, but is close to the earpiece 15, so that a high output sound pressure level can be obtained with the piezoelectric vibrator 12 having a small output.
Further, the upper rear side of the housing 11 is a portion where the user of the portable communication terminal device hardly touches the hand, and the piezoelectric vibrator 12 can vibrate without being affected by the outside, and can generate sound. Of course, the upper rear side of the housing 11 is not touched by the user of the portable communication terminal.

[0017]

As described above, in the portable communication terminal according to the present invention, the piezoelectric vibrator 12 having a large output as a sound source.
The piezoelectric vibrating body 12 is fixed to the inner wall of the housing 11 of the portable communication terminal by using the piezoelectric vibrating body 12, so that the housing 11 of the portable communication terminal itself is used as an acoustic box, and a high sound pressure level is obtained. Can be obtained.
An ear cover 15 for emitting sound to the outside is provided in the housing 11, and the piezoelectric vibrating body 12 is fixed to an inner wall of the other wall opposite to the wall provided with the ear cover 15, thereby providing an ear. Stable sounding is possible without being suppressed by vibrations caused by the ears or the like of the person applied to the application unit 15.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal side view showing an example of a portable communication terminal according to the present invention.

FIG. 2 is a partially longitudinal side view showing another example of the portable communication terminal according to the present invention.

FIG. 3 is an exploded perspective view showing an example of a piezoelectric acoustic device used in a conventional portable communication terminal as viewed from the bottom.

FIG. 4 is a vertical sectional side view showing a state where the piezoelectric acoustic device is attached to a housing of a portable communication terminal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Housing 12 Piezoelectric vibrator 15 Housing ear contact part 16 Sound emission hole 18 Battery

Claims (6)

[Claims] In a portable communication terminal provided with an ear cover (15) for applying a user's ear to an outer wall of a housing (11), a piezoelectric vibrator (1) is provided on an inner wall of the housing (11).
(2) A portable communication terminal, wherein (2) is fixed. 2. An ear cover (1) of said housing (11).
The portable communication terminal according to claim 1, wherein a piezoelectric vibrator (12) is fixed to an inner wall of the other wall facing the wall provided with (5). 3. The portable device according to claim 2, wherein the piezoelectric vibrator is fixed to an inner wall of a wall portion on which a battery is detachably attached to the housing. Communication terminal. 4. The portable communication terminal according to claim 2, wherein the piezoelectric vibrator is fixed to a position of the housing facing the ear cover. 5. A sound emission hole (16) in the earpiece (15).
The portable communication terminal according to any one of claims 1 to 4, further comprising: 6. The portable communication terminal according to claim 5, wherein the sound emitting hole has a braking function.