JP2013115549A - Drainage structure and drainage method for speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily discharge water entered into a speaker mounted on an electronic apparatus without deteriorating sound quality.SOLUTION: The inside of a speaker 20 mounted in a housing 12 of a smartphone 10 is partitioned by a diaphragm 24. A first space 40 including a piezoelectric element 30 is closed, and a second space 42 and a sound release hole 14 disposed in the housing 12 are connected to each other via a sound guide path 26. A water repellent function is imparted to an inner wall of the sound guide path 26 and an inner wall of a case 22 of the speaker 20 that forms the second space 42. When water enters the inside of the speaker 20, the diaphragm 24 is vibrated by inputting as a first signal a sinusoidal signal or a triangular wave signal of 200-400 Hz. Consequently, the water that enters the second space 42 and stays on the diaphragm 24 is divided into micro liquid drops dischargeable from the sound guide path 26, and the surface area of the liquid drops is increased, thereby facilitating evaporation (or drying) thereof.

Description

  The present invention relates to a drainage structure and drainage method for a speaker mounted on an electronic device such as a mobile phone, a smartphone, or a game machine, and particularly relates to a drainage technique using a piezoelectric speaker.

  In recent years, as the usage environment of mobile devices is expanding, it is also assumed that the device may be exposed to rain water or the like, or may be submerged in water for a short time. In order to prevent the portable device from being damaged even under such an environment, it is necessary to have a housing structure that prevents water from entering the inside of the device. However, in order to exert the function of the speaker (including the receiver), it is essential to open a hole leading to the outside in the housing of the device. Therefore, conventionally, when waterproofing the sound emission part of the speaker, a sufficiently large waterproof cloth (eg, Gore-Tex (registered trademark)) is pasted between the speaker and the outside, and the waterproof cloth is vibrated. The sound was generated by doing. In addition, there is a structure in which the diaphragm of the speaker is regarded as a waterproof membrane and the shape of the passage (sound guiding path) leading to the diaphragm and the affinity for water are controlled so that water can be easily discharged to the outside.

  For example, in the following Patent Document 1, the interfacial tension between water is reduced by blasting a region of a back surface of a cover member that covers a speaker in which there are many sound emission holes through which the sound of the speaker passes. By ensuring the specified roughness and improving the affinity with water around each sound emission hole, the water attached to the sound emission hole is prevented from staying there due to surface tension, and the sound emission holes It is disclosed that a situation where water is blocked is prevented. In addition, a plurality of vertically arranged sound emitting holes are connected by a guiding groove, and water adhering to the sound emitting hole is effectively allowed to flow downward through the guiding groove.

JP 2004-193291 A

  However, in recent portable devices, miniaturization and high functionality are progressing, and it is required to make the sound guide path required for the speaker mounting and the opening provided in the housing as small as possible. Yes. For this reason, when waterproofing is performed with a waterproof cloth, there is a problem in that the area of the waterproof cloth cannot be taken sufficiently and the sound pressure is lowered and the sound quality is deteriorated. In addition, regarding the processing for reducing the interfacial tension described in Patent Document 1 and the structure for facilitating the discharge of water to the outside, once the sound guide path is narrowed, the water that has once entered the interior is easily affected by the surface tension. There is also a problem that it is not discharged to the outside.

  The present invention pays attention to the above points, and in a speaker mounted in a housing of an electronic device, a drainage structure that makes it easy to drain water that has entered the speaker without deteriorating sound quality, and The purpose is to provide a drainage method.

  The present invention is a drainage structure of a speaker mounted inside a housing of an electronic device, and the speaker as a whole is supported so that a piezoelectric element supports the periphery of a diaphragm attached to one main surface. The speaker is covered with a case, and the inside of the speaker is sealed with a first space on the side where the piezoelectric element is provided by the diaphragm, and a second space on the side where the piezoelectric element is not provided Sound emission holes provided on the surface of the housing are connected by a sound guide path, and the inner wall of the speaker case forming the second space and the inner wall of the sound guide path are water repellent. In addition, the piezoelectric element of the speaker is characterized in that the water that has entered the second space is divided into fine droplets by inputting a driving signal of 200 to 400 Hz.

  One of the main forms is characterized in that the inner wall of the speaker case forming the second space and the inner wall of the sound guide path are coated with a water repellent. In another aspect, the inner wall of the speaker case forming the second space and the inner wall of the sound guide path are formed of a material having water repellency.

  In another invention, by inputting a 200-400 Hz sine wave signal or a triangular wave signal as a first signal to the piezoelectric element of the speaker having the drainage structure according to any one of claims 1 to 3, The water that has entered the second space is divided into fine droplets that can be discharged to the outside through the sound guide path. One of the main forms is characterized in that a sine wave signal having a frequency 3 to 5 times the frequency of the first signal is input as the second signal together with the first signal. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

  According to the present invention, the interior of the speaker mounted in the housing of the electronic device is partitioned by the diaphragm, the first space on the side where the piezoelectric element attached to the diaphragm is present is sealed, and there is no piezoelectric element. A sound emitting hole provided in the housing is connected to the inner space of the sound guiding path and the inner wall of the speaker forming the second space with a water repellent function. Give. And, since the piezoelectric element is input with a signal of 200 to 400 Hz and vibrated, the water that has entered the second space is divided into fine droplets that can be discharged from the sound guide path. Water that has entered the interior can be easily discharged without deteriorating the sound quality of the speaker.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the smart phone of Example 1 of this invention, (A) is the whole external appearance perspective view, (B) is the end surface which cut | disconnected said (A) along the # A- # A line and looked at the arrow direction (C) is a partially enlarged view of (B), and (D) is an external perspective view of the speaker.

  Hereinafter, the form for implementing this invention is demonstrated in detail based on an Example.

  First, Embodiment 1 of the present invention will be described with reference to FIG. The present invention is a technique related to the discharge of water that has entered the interior of a speaker mounted on an electronic device such as a mobile phone, a smartphone, or a game machine. In this embodiment, a smartphone will be exemplified and described as the electronic device. FIG. 1 is a diagram illustrating a smartphone according to the present embodiment, where (A) is an overall perspective view of the smartphone, and (B) is a view of (A) cut along line # A- # A and viewed in the direction of an arrow. End view, (C) is a partially enlarged view of (B), and (D) is an external perspective view of the speaker.

  As shown in FIG. 1A, the smartphone 10 of this embodiment includes a display panel 18 on a part of the surface 12A side of the housing 12, and the surface 12A has a sound emitting hole of a built-in speaker. 14 and an opening 16 for an operation switch. Here, the direction in which the display panel 18 is visually viewed is defined as the front side (or upper side), and the opposite direction is defined as the back side (or lower side). A speaker 20 is mounted inside the housing 12 as shown in FIG. In FIG. 1B, for ease of explanation, illustration of a portion related to the display panel 18 in the housing 12 is omitted, and only the speaker 20 is shown.

  As shown in FIG. 1C, the speaker 20 has a structure in which a piezoelectric element 30 is attached to one main surface of a diaphragm 24, and the whole is configured to support the periphery of the diaphragm 24. Covered with a case 22. The inside of the case 22 is sealed by the diaphragm 24 so that water does not enter the first space 40 on the side where the piezoelectric element 30 is provided (the back surface 22B side). Further, the second space 42 on the side where the piezoelectric element 30 is not provided (surface 22B side) is connected to the sound emitting hole 14 provided on the housing surface 12A via the sound guide path 26. . The airtightness of the connecting portion between the case 22 and the sound guide path 26 is maintained. In the present embodiment, the inner wall of the sound guide path 26 and the inner wall of the speaker case 22 forming the second space 42 have a water repellent function. As shown in FIG. 1C, the water repellent function may be provided with a coating 28 made of a water repellent such as Teflon (registered trademark), or the sound guide path 26 and the case 22 may be made water repellent. You may implement | achieve by comprising with the material which has.

  The piezoelectric element 30 may have any shape and configuration as long as it undergoes bending vibration. However, since it is difficult to obtain a high voltage in a portable device, a piezoelectric layer and an electrode layer are usually laminated. A laminated element is used. The piezoelectric element 30 may have a single plate structure that is not stacked at all depending on the structure of the electronic device to be mounted. As the material of the piezoelectric layer, for example, a piezoelectric material obtained by adding an additive to lead zirconate titanate is used, but other materials may be used as long as they are generally known piezoelectric ceramics. . As a material of the electrode layer, various known electrode materials such as silver and platinum can be used. Further, the diaphragm 24 may be made of a material and structure necessary for obtaining sufficient acoustic characteristics. However, in consideration of the intrusion of water into the speaker 20, the diaphragm 24 is insulated with an insulating material or metal. It is necessary to use the applied material. The piezoelectric element 30 is attached to the diaphragm 24 with an adhesive or the like.

  In the smartphone 10 configured as described above, when the casing 12 is splashed with water or the casing 12 is submerged in water, the speaker 20 passes through the sound guide path 26 through the sound emitting hole 14. Water enters the internal space. Even if a mesh is stretched mainly on the sound emitting hole 14 for the purpose of dust prevention, the mesh opening of the mesh must be 50 μm or more which does not hinder the air flow. Intrusion cannot be prevented. In addition, the width W of the sound guide path 26 (see FIG. 1 (D)) is often 1 mm or less and 0.5 mm or less depending on the equipment. Even if the casing 12 is simply turned upside down, The water that has entered the second space 42 of the speaker 20 is not easily discharged to the outside. Even if an audio signal is input to the speaker 20 while water remains in the interior, the vibration of the diaphragm 24 is hindered by water, and sufficient sound cannot be obtained.

  However, in the present embodiment, the structure of the speaker 20 is configured as described above, and the internal water can be easily discharged by following the procedure described below. For this purpose, first, a sine wave signal or a triangular wave signal of 200 to 400 Hz is input to the piezoelectric element 30 of the speaker 20 as a first signal. The amplitude of the first signal is the maximum rating of the speaker 20. The first signal is input for 3 seconds or more. In this case, it is desirable that the sound emitting hole 14 is directed downward. When the first signal is input, the diaphragm 24 vibrates, and the water staying in the inner wall of the second space 42 or the diaphragm 24 is divided into fine droplets that can pass through the sound guide path 26. Then, it is easily discharged to the outside through the sound guide path 26 subjected to water repellent treatment. That is, even if the width W of the sound guide path 26 is very narrow, such as 1 mm or less, the water that has entered the inside of the speaker 20 is made into small droplets to increase the surface area and facilitate evaporation (or drying). So that it can be discharged easily.

  In addition to the first signal described above, a sine wave signal having a frequency 3 to 5 times the frequency of the first signal may be added as the second signal. When the second signal and the first signal are applied simultaneously, the force for dividing water into droplets is more efficiently applied. Further, since the second signal gives a large displacement to the diaphragm 24, the divided droplets can be moved efficiently. These synergistic effects can further facilitate water discharge.

Next, an experimental example of the present embodiment will be described. A speaker 20 in which a piezoelectric element 30 in which six piezoelectric layers having a size of 18 × 14 mm and a thickness of 18 μm are laminated is attached to a diaphragm 24 having a size of 18 × 14 mm and a thickness of 0.1 mm, and a width W is 0. A housing 12 connected to the sound emission hole 14 with a sound guide path 26 of 5 mm was produced. The produced housing 12 was submerged to a depth of 1.5 m and left for 1 hour. Then, after taking out and wiping off the water that was attached to the outside, a signal was input to the piezoelectric element 30 at the frequency and time shown as Experimental Examples 1 to 5 in Table 1 below, and the signal was input before and after submersion. Later, sound pressure degradation was confirmed. Moreover, sound pressure deterioration was confirmed as Comparative Examples 1-4 also about the case where a frequency and time were out of the range mentioned above. For Experimental Examples 4 and 5, the upper side of the input frequency indicates the first signal and the lower side indicates the second signal. As shown in Table 1, in Experimental Examples 1 to 5, there was no or very little sound pressure deterioration, but in Comparative Examples 1 to 4, it was confirmed that the sound pressure deterioration was large.

  As described above, according to the first embodiment, the speaker 20 mounted in the housing 12 of the smartphone 10 is partitioned by the diaphragm 24 and the piezoelectric element 30 attached to the diaphragm 24 is on the first side. 1 space 40 is hermetically sealed, and the second space 42 on the side where the piezoelectric element 30 is not present and the sound emitting hole 14 provided in the housing 12 are connected by the sound guide path 26 and the inner wall of the sound guide path 26 In addition, a water repellent function is imparted to the speaker inner wall forming the second space 42. Then, the diaphragm 24 is vibrated by inputting a first sine wave or triangular wave signal of 200 to 400 Hz to the piezoelectric element 30, enters the second space 42, and stays on the diaphragm 24. The divided water is divided into fine droplets, and the surface of the droplets as a whole is increased to facilitate evaporation (or drying). It is possible to discharge to the outside. Further, if necessary, in addition to the first signal, a second signal having a sine wave having a frequency 3 to 5 times the frequency of the first signal is added to give a large displacement to the diaphragm 24. The efficiency of water droplet formation can be increased, and the drainage function can be further improved.

In addition, this invention is not limited to the Example mentioned above, A various change can be added in the range which does not deviate from the summary of this invention. For example, the following are also included.
(1) The shapes, dimensions, etc. shown in the above embodiments are merely examples, and may be changed as appropriate. For example, in the first embodiment, the speaker 20 is rectangular, but it may be circular. The width W of the sound guide path 26 can be appropriately changed according to the use of the electronic device on which the speaker 20 is mounted.
(2) In the above-described experimental example, the piezoelectric element 30 in which six piezoelectric layers are stacked is used. However, the number of stacked layers is also an example, and may be increased or decreased as necessary. There may be. In addition, the laminated element may have a bimorph structure or a unimorph structure.
(3) In the above-described embodiment, the speaker 20 has been described as an example. However, the speaker referred to in the present invention represents a speaker in a broad sense, and the technique of the present invention can naturally be applied to a receiver.
(4) Various known materials can be used as the material for forming the piezoelectric element 30.
(5) In the above embodiment, the smartphone 10 is described as an example of the electronic device to which the present invention is applied. However, this is also an example, and the present invention is an electronic device equipped with a speaker function, such as a mobile phone or a game machine. Applicable to all devices. The same applies to a receiver for calls.

  According to the present invention, the interior of the speaker mounted in the housing of the electronic device is partitioned by the diaphragm, the first space on the side where the piezoelectric element attached to the diaphragm is present is sealed, and there is no piezoelectric element. A sound emitting hole provided in the housing is connected to the inner space of the sound guiding path and the inner wall of the speaker forming the second space with a water repellent function. Give. Then, by inputting a signal of 200 to 400 Hz to the piezoelectric element, the water that has entered the second space is divided into fine droplets that can be discharged from the sound guide path, thereby improving the sound quality of the speaker. Since water that has entered the interior is easily discharged without causing deterioration, it can be applied as a waterproof technology for speakers mounted on electronic devices. In particular, it is suitable for a portable electronic device that may be splashed with water or submerged in water.

10: Smartphone 12: Housing 12A: Front surface 12B: Rear surface 12C: Side surface 14: Sound emission hole 16: Opening 18: Display panel 20: Speaker 22: Case 22A: Upper surface 22B: Rear surface 24: Diaphragm 26: Sound guide path 28: Coating 30: Piezoelectric element 40: First space 42: Second space

Claims (5)

A speaker drainage structure mounted inside the housing of an electronic device,
The speaker is entirely covered with a case so that the piezoelectric element supports the periphery of the diaphragm attached to one main surface,
Inside the speaker, the first space on the side where the piezoelectric element is provided is sealed by the diaphragm, and is provided on the second space on the side where the piezoelectric element is not provided and on the surface of the housing. Are connected by sound guide paths,
The inner wall of the speaker case forming the second space and the inner wall of the sound guide path have water repellency,
A speaker drainage structure, wherein the piezoelectric element of the speaker divides the water that has entered the second space into fine droplets upon input of a driving signal of 200 to 400 Hz.   The speaker drainage structure according to claim 1, wherein a coating with a water repellent agent is applied to an inner wall of a speaker case forming the second space and an inner wall of the sound guide path.   The speaker drainage structure according to claim 1, wherein an inner wall of the speaker case forming the second space and an inner wall of the sound guide path are formed of a material having water repellency.   A sine wave signal or a triangular wave signal of 200 to 400 Hz is input as a first signal to the piezoelectric element of the speaker provided with the drainage structure according to any one of claims 1 to 3, thereby the second space. A method for draining a speaker, wherein water that has entered the space is divided into fine droplets that can be discharged to the outside through the sound guide path.   5. The speaker draining method according to claim 4, wherein a sine wave signal having a frequency of 3 to 5 times the frequency of the first signal is input as the second signal together with the first signal.

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