JPH1126973A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently reduce the height of an electronic apparatus, irrespective of the height of pawls necessary for upper and lower covers, by alternately engaging pawls of the upper and the lower covers with the outside surface of a frame base. SOLUTION: Pawls 13 engaged with the outside surface 12 of a frame base 11 are engaged with each other, and both an upper cover 14 and a lower cover 15 are surely fixed to the frame base 11. The tip parts of the pawls 13 of the upper cover 14 are made lower than or equal to a printed circuit board position of the outside surface of the frame base 11, and the tip parts of the pawls 13 of the lower cover 15 are made higher than or equal to the printed circuit board position of the outside surface of the frame base 11. Thereby the height of an electronic apparatus is not always restricted by the height of the pawls 13 of the covers, so that the height of the electronic apparatus can be sufficiently reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a case where a surface of a circuit board is covered with a shield case for electromagnetic shielding, such as a high-frequency module in a radio equipment such as a small television, a portable VTR or a portable telephone or a cordless phone. The present invention relates to a structure for mounting electronic devices, particularly upper and lower covers to a shield base, and to a structure of a thin electronic device having a low base height.

[0002]

2. Description of the Related Art In a high-frequency module such as a tuner such as a television or a VTR, and a mobile phone or a cordless phone, a metal shield case is provided around a circuit board in order to shield electromagnetic waves from a high-frequency circuit mounted on the circuit board. ing. This shield case generally comprises a frame base surrounding the printed circuit board and upper and lower covers having locking claws for locking the frame base. The conventional attachment of the shield case to the circuit board is as shown in FIG.

[0003] That is, the mounting of a base 81 for forming a so-called outer frame of a shield case and a circuit board is performed by the base 81.
The upper cover 82 and the lower cover 83 are fitted into the upper opening and the lower opening of the base 81, respectively, after soldering or the like, and the entire printed circuit board is sealed in a shield case. To cover it. At this time, the printed circuit board and the base 81 are fixed with solder or the like, but the upper cover 82 and the lower cover 8 are fixed.
Reference numeral 3 designates detachable elastic locking without using solder or the like. That is, the upper cover 82 and the lower cover 83 are fixed to the base 81 by the tongue piece 84 shown in FIG.

The advantage of fixing without using solder or the like is that it may be necessary to remove the upper cover 82 and the lower cover 83 for adjustment in the production process and adjust components such as coils, and also to make a printed circuit board. If a part of the upper electronic component is defective, the upper cover 82 and the lower cover 8
3 so that it can be easily checked by removing it. The upper and lower openings of the base 81 are covered by an upper cover 82 and a lower cover 83 made of the same material as the base 81, but electromagnetic shielding is possible because it is necessary to elastically press the outer surface of the base 81. And an elastic material is used.

Next, a brief description will be given of a method of manufacturing this base. This base is formed by punching a sheet of material into a developed shape 61 such that a predetermined base is formed as shown in FIG. Then, the base 81 is completed. At this time, the width h of the outer surface serving as the outer frame of the base becomes the height of the base. FIG. 10 is a sectional view of the electronic device. That is, the width corresponding to the outer frame portion of the base described above corresponds to the height h in FIG. 10, and the separately formed upper and lower covers are elastically attached to the base from above and below as shown in FIG. The height of the electronic device is locked by the locking claw, and the height of the electronic device includes the thickness of the cover.

The upper and lower covers are also formed of the same material as the base material, and electromagnetically form part of an electronic circuit formed on the printed circuit board. Is insufficiently locked,
If the state of locking changes due to vibration or the like, the characteristics of the electronic circuit formed on the printed circuit board will be affected. Therefore, the upper and lower covers must be securely fixed to the base, and from this viewpoint, the locking claws of the upper and lower covers have sufficient strength against the outer surface of the base and have sufficient elasticity. It must be. Therefore, as shown in FIG. 11, the height d1 of the locking claws formed on the upper and lower covers is required to be about 2.5 mm or more as shown in FIG. 11, and it is technically difficult to further shorten the locking claws. is there. Since it is necessary to keep a predetermined distance d2 between the locking claws of the upper and lower covers, the electronic device in a state where the cover is covered from above and below is as shown in FIG. Becomes

[0007]

The downsizing of electronic devices in recent years is particularly remarkable in RF modules used for cordless phones, portable telephones and the like, and an extremely thin form as well as the width and volume is required. ing. However, as described above, in order to cover the cover from above and below with respect to the base and securely fix the cover, at least the bending height of the locking claw needs to be 2.5 mm, and between the upper and lower locking claws. Also requires a certain interval,
It has been difficult to make this type of electronic equipment thinner than about 5 mm.

On the other hand, it is conceivable to omit either the upper cover or the lower cover to make the base have a bottom. However, in such a case, it is assumed that some of the electronic components on the printed circuit board are defective. In some cases, it is not appropriate to check the inside of the device and it is not appropriate. In addition, as a matter of course, it is conceivable to make the height of the locking claw sufficiently smaller than 2.5 mm. However, in such a case, the upper and lower covers are not securely locked to the base, and due to vibration, etc. The distance between the cover and the base fluctuates, and the performance of the electronic device fluctuates in combination with the electronic circuit formed on the printed circuit board, which is not appropriate. As described above, in the conventional technology,
The height of this type of electronic equipment cannot be made sufficiently smaller than about 5 mm, and there has been a problem that it has not been possible to sufficiently cope with the recent miniaturization of RF modules used in cordless phones and mobile phones. .

[0009]

In order to solve the above-mentioned problems, the present invention comprises a frame base, a printed circuit board surrounded by the frame base, and upper and lower covers having locking claws. An electronic device is provided, wherein the locking claws of upper and lower covers are alternately locked on the outer surface of the frame-shaped base. Further, among the locking claws, there is provided an electronic device in which one arranged on the end side of each side of the upper and lower covers is narrower than one arranged on another part.

[0010] Further, the tip of the locking claw of the upper cover is located at or below the printed circuit board position on the outer surface of the frame-shaped base, and the tip of the locking claw of the lower cover is shaped like the frame. An electronic device is provided that extends beyond the printed circuit board position on the outer side of the base. Further, the frame-like base provides an electronic device having an outer surface height of 8 mm or less and 2.5 mm or more.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. The invention according to claim 1 is an electronic device comprising a frame base, a printed circuit board surrounded by the frame base, and upper and lower covers having locking claws as described above, wherein An electronic device in which locking claws of upper and lower covers are alternately locked on an outer surface.

The present invention is specifically as shown in FIG. 1, in which locking claws 13 locked on an outer surface 12 of a frame-shaped base 11 are locked so as to mesh with each other. Therefore, the height of the electronic device is not necessarily limited to the height of the locking claw 13 of the cover. Also,
The upper cover 14 and the lower cover 15 are securely fixed to the base 11 because they are alternately locked. If this is not a staggered position, for example, if the locking claws 13 of the upper cover 14 are arranged on the left side and the locking claws 13 of the lower cover 15 are arranged on the right side, there are no claws. The cover becomes unstable, and the distance between the cover and the base fluctuates due to vibration or the like, which adversely affects the characteristics of the electronic device.

Although not claimed here, what is surrounded by the frame-shaped base is not limited to the printed circuit board, but functions similarly to the printed circuit board, for example, an electronic circuit is formed on a ceramic substrate. It goes without saying that the same applies to such a case. In addition, the upper and lower covers do not necessarily cover the entire upper and lower opening surfaces of the base, and one or both of the lower cover and the upper cover may be covered by only a part of the opening surface. It may be something. Further, it goes without saying that the frame-shaped base is not necessarily limited to one completely surrounding the printed circuit board, and may include a case formed so as to surround a part of the printed circuit board.

Various shapes can be considered for the shape of the locking claw. In addition to the one whose tip portion is a pressing point against the outer surface of the base, not the tip portion but the portion receded from the tip portion is bent to form a V shape, and the portion presses the outer surface of the base. Things are also included. Various widths of the locking claws are conceivable. Although the width of the locking claw is not necessarily limited, the width of the locking claw is about 2 mm to 8 mm.
It is appropriate to design the thickness appropriately on the order of mm.
As a result, the lower claws are stuck on the outer surface of the base. It faces a portion where there is no locking claw, but this portion requires a predetermined interval. However, the effect of the present invention is not affected even when the portions partially overlap.

[0015] The arrangement of the locking claws provided on the upper cover and the lower cover is preferably as even as possible with respect to the covers. As described above, the locking claws are concentrated in part,
Also, if there are many other parts without locking claws, the locking of the cover to the base becomes unstable, which affects the characteristics of the electronic device. Further, in the present invention, the locking claws of the upper cover and the lower cover are alternately locked to the outer surface of the base, so that, in principle, the adjacent locking claws come out of the upper and lower covers, respectively. However, a certain distance is required between the locking claw and the adjacent locking claw.
However, it is also possible to divide a part of the locking claw of the upper cover or the lower cover into two parts, and to protrude a part of the printed circuit board from the outer surface of the base therebetween.

As a specific example of this, a printed circuit board is partially protruded to the outside from an opening provided on the outer surface of the base, and a tongue-shaped cutout is provided on a part of the outer surface of the base. There is a method in which a flaky cutout is penetrated through an insertion hole provided in the protruded printed circuit board to secure the ground between the base and the printed circuit board. In this case, since the printed circuit board protrudes outside from the outer surface of the base, locking claws cannot be provided on the upper cover and the lower cover at that portion.

However, when there is a printed circuit board protruding outside from the outer surface of the base as described above, the upper cover and the lower cover are bent in a U-shape to elastically lock the outer surface. Since the outer surface of the printed circuit board can be arranged inside the outermost surface of the electronic device by the bending height of the hooks bent in the shape of a square, the bending height of the hooks It also has a function of protecting the printed circuit board protruding from the outer surface of the base by the locking claw.

Next, the second aspect of the present invention will be described. The invention according to claim 2 is the electronic device according to claim 1, wherein, of the locking claws, those arranged at the ends of the upper and lower covers are narrower than those arranged at other portions. The present invention is as shown in FIG. That is, in the electronic device according to the present invention shown in FIG. 2, the width of the locking claws 23a at the outermost portions of the upper cover 24 and the lower cover 25 is locked at another portion, that is, at the center of the base. Locking claw 23
The width is smaller than the width of b. The reason for making the width narrow in this way is that the locking claw 23 must be
This is to make it exist at the left and right ends of the reference numeral 25.

For example, if the widths of the locking claws are all the same as the width of the locking claws locked at the center of the base, the outermost portion of the upper cover or the lower cover is engaged with the cover. A situation occurs in which the pawl cannot be provided or the base cannot be covered, which is not appropriate. Therefore, as in the present invention, the width of the locking claws arranged at the ends of the upper and lower covers is made smaller than the width of the locking claws arranged at other portions, and the locking claws are always provided at the left and right ends of the cover. It is necessary that the cover can be securely fixed to the base. It is necessary to always provide a locking claw at each of the left and right ends.

In the embodiment shown in FIG. 2, the lower cover does not always seem to cover both ends of the base. However, the locking claw and the cover on the other side are cut out in an L shape. The structure is such that the cover is securely fixed to the base. The width of the locking claws arranged at the ends of the upper and lower covers must be at least about 2 mm. If the width is smaller than this, the strength of the locking claw is weakened, and locking to the outer surface of the base is not reliably performed. Actually, a width of about 2 mm to 3 mm is preferable.

Next, the invention according to claim 3 will be described with reference to FIG. According to a third aspect of the present invention, the top end of the locking claw 33 of the upper cover has a position on the printed circuit board 32 on the outer surface of the frame-shaped base (a dotted line indicated by an arrow in the drawing).
The electronic device according to claim 1, wherein the lower claw of the lower cover has a tip portion extending to a position not less than a position of the printed circuit board 32 on the outer surface of the frame-shaped base. . Thus, the locking claws 33 of the upper cover,
The purpose of defining the position of the distal end of the locking claw 34 of the lower cover is to securely fix the locking claw to the base.

As described above, the printed circuit board 32 is surrounded inside the frame-shaped base. However, since the printed circuit board 32 is arranged exactly on the frame-shaped base outer surface 35, the frame-shaped base is formed. The strength of the base is highest at the portion along the printed circuit board 32. Therefore, when the locking claws 33 and 34 are locked to the outer surface 35 of the frame base, the pressing point should be a position where the printed circuit board 32 is disposed inside the outer surface of the frame base. It is the most rational in strength.

When the pressing point of the locking claw is set at a point farther from the position of the printed circuit board, the strength of the frame-shaped base is weakened. Inconveniences such as distortion and breakage of the solder connection between the printed circuit board and the frame-shaped base occur. Therefore, it is possible to press the locking claw against the frame base with a high pressing force near the position of the inner printed circuit board on the outer surface of the frame base. In addition, as described above, the strength and elasticity of the locking claw of the cover cannot be secured unless the height of the locking claw is greater than a certain height.

Therefore, if the upper and lower covers are securely locked with respect to the frame base in consideration of these conditions, the tip of the locking claw of the upper cover is positioned on the outer surface of the frame base. It is preferable that the lower end of the lower cover is located above the position of the printed circuit board on the outer surface of the frame base. Of course, "
`` More than '' does not mean that it is required to be farther away from and below the printed circuit board, and that it is farther away than the printed circuit board. It is intended. In addition, since it is "less than or equal to", it goes without saying that the case where the front end is at the position of the printed circuit board on the outer surface is included.

Next, the invention according to claim 4 will be described. According to a fourth aspect of the present invention, there is provided the electronic device according to the first aspect, wherein an outer surface height of the frame-shaped base is 8 mm or less and 2.5 mm or more. As described above, the present invention has been made in response to the recent miniaturization of electronic devices, particularly the reduction in thickness, but the height is determined by the height of the outer surface of the frame-shaped base. The effect of the present invention is particularly remarkable when the height is about 8 mm or less. In the case of more than that, it is possible to secure a sufficient height of the locking claw of 2.5 mm. Therefore, it is possible to use not only the configuration of the present invention but also the conventional configuration. When the height of the outer surface of the base becomes less than about 8 mm, it becomes difficult to secure the height of the locking claw of about 2.5 mm or more.

Therefore, the present invention is particularly effective when the height of the outer surface of the frame base is 8 mm or less. For example, in the embodiment as shown in FIG. 4, the height of the electronic device is about 4 mm, the height of the frame base is about the same, and the height of the locking claw is 2.5 mm. According to the method, the height must be at least 5 mm or more, and it is impossible to realize an electronic device having such a thin thickness. However, by adopting the configuration as in the present invention, the height of the electronic device can be designed without depending on the height of the locking claw, so that the electronic device having the upper and lower covers as high as 4 mm is realized. You can do it.

[0027]

As described above, according to the present invention, in an electronic device which requires upper and lower covers, the height of the electronic device can be sufficiently increased regardless of the height of the locking claws required for the upper and lower covers. An electronic device that has an effect of being thinner and sufficiently satisfies the demand for miniaturization of an electronic device that has been remarkable in recent years, such as an electronic tuner or an RF module, can be realized.

[Brief description of the drawings]

FIG. 1 is a side view of an electronic device of the present invention in which upper and lower covers are locked.

FIG. 2 is a side view of the electronic device of the present invention in which the width of locking claws at both ends of the upper and lower covers is reduced.

FIG. 3 is a side view showing a position of a printed circuit board and a locking claw of the electronic device of the present invention.

FIG. 4 is a side view of an electronic device having an outer surface height of 4 mm according to the present invention.

FIG. 5 is a perspective view of an electronic device in which upper and lower covers are locked to a base according to the present invention.

FIG. 6 is a top view in which a base material is punched into a developed view shape of the base.

FIG. 7 is a perspective view of a punched plate made of a base material assembled on a base.

FIG. 8 is a perspective view showing a state before the upper and lower covers are locked to the base by the tongue pieces.

FIG. 9 is a perspective view of a conventional electronic device in which upper and lower covers are locked to a base.

FIG. 10 is a conceptual cross-sectional view of a conventional electronic device before the upper and lower covers are covered.

FIG. 11 is a conceptual sectional view of a conventional electronic device with upper and lower covers covered.

FIG. 12 is a side view of a conventional electronic device having upper and lower covers.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Frame-shaped base 12 Outer side surface 13 Locking claw 14 Upper cover 15 Lower cover

Claims (4)

[Claims] 1. An electronic device comprising a frame-shaped base, a printed circuit board surrounded by the frame-shaped base, and upper and lower covers having locking claws. An electronic device in which the locking claws of the cover are alternately locked. 2. The electronic device according to claim 1, wherein, of the locking claws, those arranged on the end sides of the respective sides of the upper and lower covers are narrower than those arranged on other portions. 3. The locking claw of the upper cover has a tip portion that is less than or equal to the printed circuit board position on the outer surface of the frame base, and the locking claw of the lower cover has a tip portion of the frame base. The electronic device according to claim 1, wherein the electronic device reaches the position of the printed circuit board on the outer surface. 4. The electronic device according to claim 1, wherein the frame-shaped base has an outer surface height of 8 mm or less and 2.5 mm or more.