HK1050441A - Mounting structure of electronic parts - Google Patents

Description

Sealing structure of electronic component

Technical Field

The present invention relates to a sealing structure for sealing various electronic components including an electronic component in which an acoustic element such as a speaker is sealed in one case, and more particularly to an electronic component sealing structure suitable for sealing a small information device such as a mobile phone.

Background

With the development of communications, the application of information devices represented by mobile phones is spreading. Most information devices use various acoustic elements for acoustic input and output, and use them for various purposes such as calling. Speakers and microphones are typical examples of such acoustic elements. These acoustic elements are often mounted inside the information device. In this case, the housing of the information device is provided with at least one opening for allowing sound to be transmitted between the assembled acoustic member and the outside of the housing. The small hole not only allows sound to pass through, but also allows various foreign substances such as moisture, dust, etc. to enter the information device.

These moisture and dust often become a cause of deterioration in the quality of the acoustic element. Further, electronic parts such as various displays that perform optical display are liable to be deteriorated in quality due to dust adhering thereto. Therefore, it is particularly common to place a diaphragm-like member between an electronic part such as an acoustic member mounted inside an information device and a case hole to prevent moisture and dust.

A mobile phone is an example of an information device, and fig. 1 is a partial sectional view illustrating an example of a structure in which electronic parts are sealed. An upper case 11A and a lower case 11B constituting a housing of a mobile phone enclose a housing inner chamber 12 in which a printed circuit board 13 is placed. A speaker body 14 is mounted as an acoustic element on this printed circuit board 13 by a surface mounting process. That is, the thin metal plates 15A and 15B are formed by protruding both side portions of the speaker main body 14 in an approximately cylindrical shape. The two terminals each have a terminal bent into an L-shape and are fixed to the surface of the printed circuit board 13 with solder 16.

The upper case 11A is opened with a sound hole 17 at a position opposite to the upper middle portion of the speaker main body 14. An annular seal member 18 and a dust-proof net 19 are installed between the speaker main body 14 and the upper case 11A, the seal member 18 being made of urethane foam (urethane foam) material and being capable of effectively discharging sound through the sound hole 17 without leaking to the inside of the cabinet. An annular first double-sided adhesive tape 21 having the same shape as the sealing member is first bonded at its upper surface to the upper case 11A and then bonded at its lower surface to the upper surface of the sealing member 18 in the same manner. A second double-sided adhesive tape 22 like a ring is bonded on its upper surface to the dust-proof mesh 19 and on its lower surface to the upper surface of the speaker body 14.

When assembling these parts, the assembly process requires: the speaker body 14 is first mounted on the printed circuit board 13 by a surface mounting method, and then the dust screen 19 is fixed on the upper surface of the speaker body 14 by the second double-sided tape 22. Another assembly process also requires: a ring-like seal member 18 is attached to a portion around the sound hole 17 of the upper case 11A with a first double-sided adhesive tape 21. When these assembly works are completed, the ring-like seal member 18 and the dust-proof net 19 are fixed with pressure so that all the parts are integrated into one piece.

According to the above-described sealing structure of the electronic part, as shown in fig. 1, the upper surface of the speaker main body 14 is pressed against the sealing member 18 with a constant pressure to come into close contact therewith. Therefore, the dust screen 19 can be bonded to the speaker main body 14, and any sound leakage can be prevented.

However, this prior art electronic part sealing structure requires a pair of double-sided tapes 21 and 22 to be attached to each part, thus requiring two separate assembly steps. Further, after the seal member 18 and the dust screen 19 are mounted in place with the double-sided adhesive tapes 21 and 22, respectively, when the two are pressed to come into close contact with each other, it is necessary to adjust the positions of these two parts. This requires some additional work. Moreover, the use of the double-sided tapes 21 and 22 for bonding one part to another requires that the bonding surfaces of the respective parts must be kept clean during the bonding process, and therefore, there arises a problem that the respective parts must be properly controlled during the assembly process.

Disclosure of Invention

Accordingly, it is an object of the present invention to provide an electronic part sealing structure which can easily mount electronic parts such as acoustic elements including speakers and other various parts.

In a first aspect of the present invention, a sealing structure of an electronic component is constituted by: (i) a housing and having an aperture formed therein for allowing the passage of sound waves therethrough, and (ii) a cylindrical member disposed between the housing and an acoustic member for input and output of sound waves and fixed in the housing at a predetermined position opposite to the aperture. One end of the cylindrical member closes a circumferential end portion of the small hole on a side facing the acoustic member, and is fitted on this circumferential end portion. The other end of the cylindrical member is in compressive contact with a surface extending along the entire edge of the aperture of the housing. The cylindrical member has a length extending from the small hole facing the tip of the acoustic member to the end of the other end of the cylindrical member on the side of the housing, the length being larger than the distance from the one end of the acoustic member to the position of close contact with the housing when the one end of the cylindrical member is held in compression with the acoustic member. And at least the other end of the cylindrical member is formed of a material which is elastic and deformable under pressure.

Thus, when the acoustic member is mounted in the housing, the other end of the cylindrical member is in pressing contact with the periphery of the housing aperture. Thereby eliminating the need for adhesives and double-sided tape.

In a second aspect of the present invention, a sealing structure for an electronic part comprises (i) a housing having an opening in the housing for allowing sound waves to pass therethrough, and (ii) a generally cylindrical member disposed between the housing and an acoustic member and fixedly mounted in the housing at a predetermined position opposite the opening for the input of sound waves and the output of sound waves. The cylindrical member is held in pressing contact with the entire circumference of the aperture by the opposed face of the acoustic member opposed to the aperture and the surface projecting along the edge of the aperture of the housing. The axial length of the cylindrical member is longer than the distance from the opposite surface of the acoustic member to the position where the housing is pressed into contact with the acoustic member, and the cylindrical member is made of a material which is elastic and deforms under pressure at least in a portion which is in contact with the opposite surface of the acoustic member and the housing.

Therefore, in the condition where the acoustic element is mounted in the housing, the other end of the cylindrical element is in press-contact with the periphery of the hole, so that an adhesive and a double-sided adhesive tape are not required.

Each of the embodiments of the present invention as described above may further comprise a plate-like member configured to block the interior of the cylindrical member and thus prevent any ingress of moisture and dust.

The plate-like member may be a net-like member having a plurality of minute holes therein. Such a plate-like element is configured to prevent moisture and dust from entering the acoustic element through the holes.

In a further feature of the invention, the electronic component sealing structure has a sealing member which deforms under pressure and which blocks between the electronic component and other components within the housing.

That is, the closing member is deformed by pressure, and the electronic parts in the case can be protected from dust left in the case.

The above objects, features and advantages of the present invention will become apparent from the following description, which is made for the purpose of illustrating preferred embodiments of the present invention, based on the accompanying drawings.

Drawings

FIG. 1 is a cross-sectional view of the main part of a mobile phone, representing an example of a prior art process of the electronic part sealing structure;

fig. 2 is a cross-sectional view of the main part of a mobile phone, showing the electronic part sealing structure according to the embodiment of the invention;

FIG. 3 is a perspective view of the electronic part sealing structure of the embodiment of FIG. 2, showing the case where the cover is mounted on the speaker after the speaker face is mounted on the printed circuit board;

fig. 4 is a cross-sectional view of the main part of a mobile phone, which represents an electronic parts mounting structure according to an improved embodiment of the present invention;

FIG. 5 is an enlarged partial cross-sectional view representing the periphery of the mask in the modified embodiment of FIG. 4.

Detailed Description

The invention will be explained below on the basis of a description of preferred embodiments.

Fig. 2 illustrates an electronic part sealing structure according to an embodiment of the present invention, and those elements that are the same as those in fig. 1 are denoted by the same reference numerals. In this embodiment, the upper and lower casings 11A and 11B constituting the mobile phone further enclose a body cavity 12, and a printed circuit board 13 is placed in the body cavity 12. A speaker main body 14 as an acoustic element is mounted on this printed circuit board 13 by SFT (surface mount technology). That is, terminals 15A and 15B made of thin metal plates are projected from both sides of the speaker main body 14 of the approximate cylinder. The ends of the two terminals are bent into L-shapes, respectively, and fixed to the surface of the printed circuit board 13 with solder 16.

The upper case 11A is opened with a sound hole 17 at a position opposite to the upper middle position of the speaker main body 14. A cover 52 is fitted over the speaker body 14, and a mesh 51 is fixed to the cover. At the upper portion of the cover 52 is a circularly disposed flange 52A having a triangular cross-section and configured to abut against the upper shell 11A.

Fig. 3 illustrates the case where the cover is coupled to the speaker after the speaker is mounted on the printed circuit board. As clearly shown in the drawing, the terminals 15A and 15B are made of a thin metal plate and project toward directions opposite to each other around the outside of the speaker body 14, and the terminals are fixed to the printed circuit board 13 with solder 16. The two terminals 15A and 15B made of thin metal plates are connected to a circuit, not shown, on the printed circuit board 13 to pass electric current for outputting an acoustic signal.

The speaker main body 14 is formed with a sound hole 61 at an intermediate position thereof, and sound is discharged outside through the sound hole 61. The cover 52 is constituted by an upper half cover 52B and a lower half cover 52C, the upper half cover 52B having a flange 52A disposed at an upper end thereof, and the lower half cover 52C being press-fitted around the outside of the speaker body 14. The cover 52 is formed as a holed cover member having a hole 62 in the center thereof and covered with the net 51, and the net 51 is cut into a circular plate and fixed inside the hole 62. The annular peripheral portion of the net 51 is fixed between the upper half cover 52B and the lower half cover 52C. As can be appreciated from fig. 2, the flange 52A, the upper half cover 52B, and the lower half cover 52C form one integral piece, and are made of an elastomer exhibiting high elasticity at room temperature. The elastomer has many excellent functions such as a strong impact absorbing ability, a high rebound resilience, a high friction coefficient, a vibration suppressing force and a sealing function. Silicon rubber may also be used instead of elastomers.

In the electronic part sealing structure described, a method of integrally fixing the net 51 to the cover 52 is described. The net 51 is a thin plate-shaped member and has a function of preventing any dust and dirt from entering the speaker 14 or the body cavity in the cabinet from the outside. Such a sheet-shaped element must be able to prevent any ingress of dust, dirt and moisture from the outside. In addition, the thin plate-shaped element must limit sound pressure attenuation to a minimum. To this end, in this embodiment, the web 51 is made of either a textile material or a porous material having a plurality of pores therein.

The mesh 51, on the other hand, has formed therein apertures 53 of any size and number. Since the cover 52 is formed by using a not-shown metal mold, the net 51 must be placed in the metal mold so as to be mounted at a predetermined position in relation to the cover 52. To this end, the net 51 is initially cut to a size slightly larger than that shown in fig. 2 or 3, and is set in a predetermined position of the metal mold. Then, when the material constituting the cover 52 is poured into the metal mold, the flange 52A, the upper half cover 52B, and the lower half cover 52C are formed integrally with each other through the hole 53. After the cover 52 is molded, any excess portion of the mesh 51 extending from the periphery of the cover is removed by cutting to obtain the size and shape shown in fig. 2 or 3.

The cover 52 formed by the above method has a portion to be fitted to the outer circumferential portion of the speaker body 14, and this fitting portion of the cover 52 has a diameter slightly smaller than that of the outer circumference of the speaker body 14. Therefore, when the elastic cover 52 is press-fitted to the outer circumferential portion of the speaker main body 14, it can be fastened to the speaker.

After the cover 52 is fixed to the speaker body 14, the speaker body 14 is surface-mounted on the printed circuit board 13 by soldering terminals 15A and 15B made of a thin metal plate to the printed circuit board. This printed circuit board 13 is then fixed in position inside the housing 11 by fixing means such as screws or the like, not shown. The flange 52A of the cover is designed to have such a shape and height that, when the printed circuit board 13 is pressed against the upper case 11A during the fixing of the printed circuit board 13 inside the housing 11, the resulting pressure deforms the flange until the flange comes into close contact with the upper case 11A. Therefore, if the position where the speaker 14 is face-mounted on the printed circuit board 13 is preliminarily determined based on the position of the sound hole 17, a very simple assembling operation of fixing the printed circuit board 13 to a predetermined position in the cabinet allows the annular flange 52A of the cover to come into close contact with the upper case 11A. Therefore, the sound generated from the speaker main body 14 can be effectively output through the sound hole 17 without leaking to the inside of the cabinet. In addition, the portion formed by the upper half cover 52B and the mesh 51 can appropriately prevent not only entry of dust, dirt, or moisture into the inside of the speaker body but also entry of the inside of the device itself through this portion.

Moreover, according to the embodiments of the present invention, since the number of constituent parts can be reduced, the gap between the upper surface of the speaker and the housing can be reduced, thus contributing to reduction in the overall size or thickness of an information device such as a mobile phone.

(modification of the embodiment)

Fig. 4 illustrates an improved electronic component sealing structure according to an embodiment of the present invention. It should be clear that in this figure those parts which are identical to those of figure 2 are identified with the same reference numerals and that the description of those parts has been omitted for the sake of brevity.

In the modification, an annular flange 11AB having an inner diameter equal to the outer diameter of the cylinder 51 is disposed in the bottom surface of the upper shell 11AA so as to project downward therefrom. Thus, within the cylindrical cavity 71 closed by the annular flange 11AB, the entire annular cover 72 can be installed together with the integral net 51.

Fig. 5 illustrates the cover 72 along with a portion of the periphery by enlarging the size. The cover 72 is made of either an elastic body or silicone rubber, and is constituted by an upper half cover 72B provided with a first flange 72A of triangular section at an upper portion thereof and a lower half cover 72D provided with a second flange 72C of triangular section at a lower portion thereof. The upper half cover 72B and the lower half cover 72D are connected together by a connecting portion 72E to form the integrated cover 72 as a whole. The connecting portion 72E is formed by filling the holes of the net 51 with an elastomer or silicone rubber.

In this modification, the diameters of the upper half cover 72B and the lower half cover 72D are slightly larger than the inner diameter of the flange 11 AB. Therefore, when the two half covers 72B and 72D are fitted into the inner surface of the flange 11AB by pressing, the cover 72 integrated with the net 51 can be placed firmly. Further, the cover 72 is formed without pressing in the height direction (vertical direction) which is a predetermined value larger than the distance from the bottom surface of the upper cabinet 11AB to the position of the upper surface of the speaker main body 14 after assembly. Therefore, in the condition where the cover 72 is inserted into the inner surface of the flange 11AB, since the speaker main body has been mounted on the printed circuit board 13, when the printed circuit board 13 is fixed at a predetermined position in the cabinet, the first flange 72A is brought into press contact with the bottom surface of the upper case 11AA and is caused to deform so as to be in close contact with the bottom surface. In addition, the second flange 72C comes into press contact with the upper surface of the speaker main body 14, and deforms while coming into close contact therewith.

As a result, the sound emitted from the speaker main body 14 can be effectively output through the sound hole 17 without entering the inside of the cabinet. Also the part formed by the upper cover half 72B of the cover and the mesh 51 prevents not only dust, dirt or moisture from entering the loudspeaker interior, but also prevents them from entering the interior of the device from the outside through this part.

Further, according to the above-described improvement, many constituent parts can be reduced, so that the gap between the upper surface of the speaker and the cabinet can be reduced, and therefore, it is advantageous to reduce the entire size and thickness of an information device such as a mobile phone.

It should be appreciated that in the various embodiments described, although a loudspeaker is taken as an example of the acoustic element, the invention is equally applicable to microphones.

Further, in the above-described respective embodiments, it is considered that the electronic parts are protected from the entry of moisture or dust and dirt from outside the housing. Thus, the method of deforming the elastomer(s) by bringing the pressure into close contact with the predetermined element will allow the electronic part to be effectively protected from the ingress of dust and moisture from the interior of the housing.

It will be apparent from the foregoing description that, according to the invention as claimed in claims 1 to 5, no adhesive and double-sided adhesive tape are required for this purpose, or they may be limited to a given purpose, since the electronic parts inside the casing are protected against the entry of moisture, or dust and dirt, by using a material that is deformable under pressure. Materials like silicone are not suitable for adhesives and double-sided tapes, so practical applications of materials like silicone can be achieved and the flexibility of choice of materials will be expanded. In addition, since a more suitable material can be used, the quality of a product on which electronic parts are mounted can be improved.

While certain preferred embodiments of the present invention have been illustrated and described in detail, various modifications and improvements can be made thereto within the scope of the appended claims.

Claims (5)

1. An electronic part sealing structure comprising:

a housing having an aperture for the passage of sound waves therethrough; and

a cylindrical member fitted to an acoustic member fixed at a predetermined position in the casing opposite to the small hole for input or output of acoustic waves;

wherein said cylindrical member has one end closing a circumferential end portion facing said small hole of said acoustic member and fitted at the circumferential end portion, and the other end in press contact with the entire extension of the edge of said housing hole; the cylindrical member extends from the small hole opposite to the end of the acoustic member to the end of the side surface of the casing at the other end, over a distance from the end of the acoustic member to the pressing surface of the casing when the cylindrical member is mounted at the one end on the acoustic member, and at least the other end of the cylindrical member is made of a material which is elastic and deforms under pressure.

2. An electronic part sealing structure comprising:

a housing having an aperture for the passage of sound waves therethrough; and

a cylindrical member having a cylindrical shape as a whole and interposed between said housing and said acoustic member, said acoustic member being fixedly disposed in a predetermined position in said housing opposite to said aperture for input and output of acoustic waves, wherein said cylindrical member is held in pressing contact with the entire circumference of said aperture between a face opposite to said aperture side and an extended face of said aperture edge of said housing, said cylindrical member has an axial length thereof larger than a distance from said face opposite to said acoustic member to a position of pressing contact of said housing, and said cylindrical member is made of a material which is elastic and deforms under pressure at least in a portion which is in contact with said face opposite to said acoustic member and said housing.

3. The electronic part sealing structure as claimed in claim 1, further comprising a thin plate-like member configured to block an inside of said cylindrical member, thereby preventing any entry of moisture and dust.

4. The electronic part sealing structure as claimed in claim 2, further comprising a thin plate-like member configured to block an inside of said cylindrical member, thereby preventing any entry of moisture and dust.

5. An electronic part sealing structure includes a sealing member that deforms under pressure and blocks an electronic part placed in a casing and other parts in the casing.