Shield case and electronic apparatus

A shield case 10 has, disposed upon a lateral plate 12, a first anchor part 123 for anchoring to a substrate, and a slit 127 which extends from a release edge part to a top plate 11, whereupon a leading end portion 127a thereof is formed upon the top plate 11.

TECHNICAL FIELD

The present invention relates to a shield case formed into box-like shape and one end being opened having a top plate and side plates in which a part of opened edges of the side plates axe fixed to a substrate on which electronic parts are mounted, and relates to an electronic apparatus using the shield case.

BACKGROUND ART

During use of an electronic apparatus incorporating a substrate on which electronic parts are mounted, especially a mobile device such as a mobile phone having high portability, a user may drop involuntarily this electronic apparatus. When the mobile device drops and hits against a floor surface, a motherboard incorporated in the mobile device may be significantly distorted, and the electronic parts on the motherboard may be separated therefrom. Thus, the electronic parts used in the mobile device are required to ensure peeling strength withstanding the distortion of the motherboard caused by a drop impact.

A mechanism of the separation of the electronic parts due to the distortion of the motherboard is that the electronic parts are not distorted even though the motherboard is distorted, stress thereof concentrates on a terminal connecting the electronic parts and motherboard, whereby the terminal or a portion around the terminal is damaged. On the basis of the mechanism, as a method of enhancing the peeing strength, there is a method that reduces rigidity of the electronic parts so that the electronic parts easily follow the distortion of the motherboard. In a module including a resin substrate, electronic parts mounted on the resin substrate, and a shield case disposed on the substrate so as to cover the electronic parts, the rigidity thereof is determined by a structure of the shield case, so that it is possible to enhance the peeling strength by optimizing the structure of the shield case.

The following Patent Document 1 discloses a shield case formed into a box-like shape and one end being opened having a top plate and side plates, and put on a substrate housed in a casing of an electronic apparatus in such a manner that opened edges of the side plates are brought into contact with a ground pattern formed on the substrate. In this shield case, a plurality of slits are formed so as to face the opened edge of each side plate and to divide the side plate into a plurality of sections.

CITATION LIST

Patent Document

SUMMARY OF INVENTION

Technical Problem to be Solved by Invention

The technique described in the Patent Document 1 can make the module so as to withstand a certain degree of the drop impact. However, it cannot be said that followability to a deformation of the mother board such as a complicated distortion is sufficient.

The present invention has been made in view of the above problem, and an object thereof is to provide a shield case capable of following also the distortion of a substrate to which the shield case is fitted and a module using the shield case.

Means for Solving Problem

To solve the above problem, a shield case according to the present invention is formed into a box-like shape and one end being opened having a top plate and a side plate, in which a part of an opened edge of the side plate is fixed to a substrate on which electronic parts are mounted, wherein the side plate has a fixing portion for fixing to the substrate, and a slit extending from the opened edge to the top plate and having a tip portion forced in the top plate.

According to the present invention, the silt extends from the opened edge of the side plate up to the top plate, and the tip portion of the slit is formed in the top plate, so that even if the substrate to which the shield case is fitted is distorted, the top plate easily follows the distortion, and a module easily follows distortion of a motherboard. As a result, stress applied to a terminal of the module is reduced, thereby enhancing peeling strength of the module.

Preferably, in the shield case according to the present invention, the tip portion is formed into a circular arc. In this preferred embodiment, by forming the tip portions into a circular arc shape, it is possible to reduce stress concentration on the tip portion, and to prevent damage due to metal fatigue even if the distortion repeatedly occurs.

Preferably, in the shield case according to the present invention, a plurality of the side plates are provided, and adjacent side plates are spaced apart from each other to form a gap therebetween. In this preferred embodiment, even if the shield case is significantly distorted, the formation of the gap between the adjacent side plates allows the adjacent side plates to foe shifted from each other, thereby suppressing damage of the side plates.

Preferably, in the shield case according to the present invention, at least one pair of the slits is formed, and the fixing portion is provided in a position sandwiched between the pair of slits in the side plate. In this preferred embodiment, the silts are formed on both sides of the fixing portion for fixing the shield case to the substrate, so that even if the substrate is distorted, the shield case easily follows the distortion, thereby reducing rigidity of the module.

Preferably, in the shield case according to the present invention, the fixing port ion includes a first fixing portion provided in a center portion of the side plate. A displacement amount caused due to distortion of the substrate is the smallest in the vicinity of the center of one side of the substrate. Thus, when the shield case is fixed to the substrate at this portion, influence on the distortion of the substrate that the rigidity of the shield case exerts can be reduced. As a result, it is possible to fix the shield case to the substrate without involving an increase in the rigidity of the module.

Preferably, in the shield case according to the present invention, second fixing portion and third fixing portion are formed so as to sandwich the first fixing portion therebetween in an extending direction of the side plate. In this preferred embodiment, in addition to the above arrangement of the first fixing portion, forming of the second fixing portion and third fixing portion so as to sandwich the first fixing portion therebetween allows more secure fixing of the shield case to the substrate.

Preferably, in the shield case according to the present invention, a slit is formed between the second fixing portion and a gap and a slit is also formed between the third fixing portion and a gap. In this preferred embodiment, even if a corner portion of the shield case is deformed, force to be applied to the second fixing portion and third fixing portion can be reduced.

Preferably, in the shield case according to the present invention, a first connecting portion is formed at an end portion of the first fixing portion on a side opposite to the top plate, a second connecting portion is formed at an end portion of the second fixing portion on a side opposite to the top plate, and a third connecting portion is formed at an end portion of the third fixing portion on a side opposite to the top plate, a length of a portion of the first connecting portion that is arranged along the substrate is longer than a length of a portion of the second connecting portion that is arranged along the substrate and a length of a portion of the third connecting portions that is arranged along the substrate.

In this preferred embodiment, a length of a portion of the first connecting portion that is arranged along the substrate is configured to be longer than a length of a portion of the second connecting portion, that is arranged along the substrate and a length of a portion of third connecting portion that is arranged along the substrate. Thus, it is possible to achieve both fixation strength of the shield case to the substrate and suppression of excessive enhancement of rigidity of the shield cased.

Preferably, in the shield case according to the present invention, a corner portion of any of the first connecting portion, the second connecting portion, and the third connecting portion is formed into a circular arc shape so as to retreat toward the top plate side in a surface perpendicular to the substrate. In this preferred embodiment, it is possible to achieve both reduction in the stress concentration which is brought about by forming the corner portion info a circular arc shape, and solder wetting-up uniformization effect which is brought about by forming the circular arc such that the circular arc retreats to the top plate side in a surface perpendicular to the substrate.

Preferably, in the shield case according to the present invention, both the second connecting portion and third connecting portion are disposed so as to be closer to a gap side. In this preferred embodiment, a distance between the second connecting portion and third connecting portion can be secured. Thus, it is possible to achieve assurance of stability of a fixing state of the shield case and to improve resistance to pressure applied from an upper surface of the shield case during mounting and the like.

Preferably, in the shield case according to the present invention, the second connecting portion and the third connecting portion are provided to be positioned inside the outermost part of a terminal electrode disposed on a rear surface of the substrate. In this preferred embodiment, when the substrate is distorted with the distortion of the motherboard, it is possible to prevent stress due to influence of the distortion from being transmitted to the second connecting portion and the third connecting portion.

An electronic apparatus according to the present invention is a device in which the above-described shield case is disposed on the substrate on which electronic parts are mounted so as to cover the electronic parts. In the present invention, there can be provided an electronic apparatus having characteristics of the above-described shield case.

Advantageous Effects of Invention

According to the present invention, there can be provided a shield case capable of following also the distortion of a substrate to which the shield case is fitted and an electronic apparatus using the shield case.

MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below with reference to the accompanying drawings. For easy understanding of explanation, in each drawing, the same reference numerals are affixed to the same components as much as possible, and redundant descriptions thereof are omitted.

A shield case which is an embodiment of the present invention will be described with reference toFIGS. 1A and 1B.FIGS. 1A and 1Bare views each illustrating a shield case10which is an embodiment of the present invention.FIG. 1Ais a plan view of the shield case10, andFIG. 1Bis a side view of the shield case10.

The shield case10has a top plate11and four side plates12. The top plate11has a substantially rectangular shape, and the four side plates12are provided to extend from individual sides of the top plate11in the same direction which is perpendicular to the top plate11. Thus, the shield case10is formed into a box-like shape and one end being opened having the top plate11and side plates12. In the shield case10, a part of an opened edge (edge portion of the side plate12on a side opposite to a side on which the side plate12is connected to the top plate11) of the side plate12is fixed to a substrate on which electronic parts are mounted.

InFIG. 1B, the side plate12has a side end portion121, a second fixing portion122, a first fixing portion123, a third fixing portion124, and a side end portion125in the order from one end towards the other end. A silt126is formed between the side end portion121and second fixing portion122. A slit127is formed between the second fixing portion122and first fixing portion123. A slit128is formed between the first fixing portion123and third fixing portion124. A slit129is formed between the third fixing portion124and side end portion125.

Thus, the side plate12has the first fixing portion123, second fixing portion122, and third fixing portion124which are a fixing portion for fixing to the substrate, and slits126,127,128and129extending from the opened edge to the top plate11.

A tip portion126aof the slit126is formed in the top plate11. Thus, the silt126is connected from the opened edge to the top plate11. Similarly, a tip portion127aof the slit127is formed in the top plate11, a tip portion128aof the slit123is formed in the top plate11, and a tip portion129aof the slit129is formed in the top plate11.

By adopting such a configuration, the slits126,127,128, and129extending from the opened edge of the side plate12reach the top plate11, and the tip portions126a,127a,128a, and129aof the slits126,127,128, and129are formed in the top plate11. Therefore, even if the substrate to which the shield case10is fitted is distorted, the top plate11easily follows the distortion.

Further, in the present embodiment, the tip portions126a,127a,128a, and129aare formed into a circular arc shape. In this manner, by forming the tip portions126a,127a,128a, and129ainto a circular arc shape, it is possible to reduce stress concentration on the tip portions126a,127a,128a, and129a, and to prevent damage due to metal fatigue even if the distortion repeatedly occurs.

Further, in the present embodiment, a plurality of the side plates are provided, and adjacent side plates12and12are spaced apart from each other to form a gap therebetween. An embodiment of the formation of this gap will be described with reference toFIG. 2.FIG. 2is a fragmentary perspective view illustrating a gap13formed between the adjacent side plates12and12.

As illustrated inFIG. 2, the adjacent side plates12and12are spaced apart from each other to form the gap13therebetween. More specifically, the side end portion121of the one side plate12and the side end portion125of the other side plate12are spaced apart from each other to form the gap13. With this configuration, even if the shield case10is significantly distorted, the adjacent side plates12and12are allowed to be shifted from each other, thereby suppressing damage of the side plates12.

Further, in the present embodiment, at least one pair of the slits is formed, and the fixing portion is provided at a position sandwiched between the pair of slits in the side plate. Specifically, the second fixing portion122which is a fixing portion is formed between the slits126and127which is a pair of slits. Similarly, the first fixing portion123is formed between the pair of slits127and128, and the third fixing portion124which is a fixing portion is formed between the slits128and129which is a pair of slits. In this manner, since the slits126,127,128, and129are formed on both sides of the fixing portions123,122, and124which are fixing portions for fixing the shield case10to the substrate, the shield case10easily follows the distortion even if the substrate is distorted.

Further, in the present embodiment, the first fixing portion123is provided in a center portion of the side plate12. A displacement amount caused due to distortion of the substrate is the smallest in the vicinity of the center of one side of the substrate. Thus, when the shield case10is fixed to the substrate at this portion, influence on the distortion of the substrate that the rigidity of the shield case exerts can be reduced. By fixing the shield case10to the substrate at the first fixing portion123formed in the center portion of the side plate12, it is possible to fix the shield case10to the substrate without involving an increase in the rigidity of the module.

Further, in the present embodiment, the second fixing portion122and third fixing portion124are provided so as to sandwich the first fixing portion123therebetween in an extending direction of the side plate12. In this manner, in addition to the above embodiment of arrangement of the first fixing portion123, forming of the second fixing portion122and third fixing portion124so as to sandwich the first fixing portion123therebetween allows more secure fixing of the shield case to the substrate.

Further, in the present embodiment, the slit126is formed between the second fixing portion122and a gap13, and the slit129is formed between the third fixing portion124and a gap13. With this configuration, even if a corner portion of the shield case10is deformed, force to be applied to the second fixing portion122and third fixing portion124can be reduced.

Further, in the present embodiment, a first connecting portion123ais formed at an end portion of the first fixing portion123on a side opposite to the top plate11, a second connecting portion122ais formed at an end portion of the second fixing portion122on a side opposite to the top plate11, and a third connecting portion124ais formed at an end portion of the third fixing portion124on a side opposite to the top plate11.

A length of a portion of the first connecting portion123athat is arranged along the substrate is configured to be longer than a length of a portion of the second connecting portion122athat is arranged along the substrate and a length of a portion of the third connecting portion124athat is arranged along the substrate. In this manner, it is possible to achieve both fixation strength of the shield case10to the substrate and suppression of excessive enhancement of rigidity of the shield case.

Further, in the present embodiment, a corner portion of any of the first connecting portion123a, the second connecting portion122a, and the third connecting portion124ais formed into a circular arc shape so as to retreat toward the top plate11side in a surface perpendicular to the substrate. This embodiment will be described with reference toFIG. 3, taking the first connecting portion123aas a representative example.FIG. 3is a view illustrating, in an enlarged manner, the first connecting portion123aof the shield case10ofFIG. 1.

As illustrated inFIG. 3, corner portions123band123cof the first connecting portion123aare each formed into a circular arc shape so as to retreat to the top plate11side in a surface (surface along the paper surface ofFIG. 2) perpendicular to the substrate. Accordingly, in each of the corner portion123band the corner portion123c, outside of the circular arc is directed to the top plate11side, and the circular arc rises up in an arch shape from the substrate side (lower side ofFIG. 2). With this configuration, it is possible to achieve both reduction in the stress concentration which is brought about by forming the corner portions123band123cinto a circular arc shape, and solder wetting-up uniformization effect which is brought about by forming the circular arc such that the circular arc retreats to the top plate11side in a surface perpendicular to the substrate.

Further, in the present embodiment, both the second connecting portion122aand the third connecting portion124aare disposed so as to be closer to a gap13side. With this configuration, a distance between the second connecting portion122aand the third connecting portion124acan be secured, thereby achieving assurance of stability of a fixing state of the shield case and improvement of resistance to pressure applied from an upper surface of the shield case during mounting and the like.

Further, in the shield case10according to the present embodiment, the second connecting portion122aand the third connecting portions124aare provided to be positioned inside the outermost part of a terminal electrode disposed on a rear surface of the substrate. This embodiment will be described with reference toFIG. 4.FIG. 4is a view illustrating a part of an electronic device ED in which the shield case10is mounted to a substrate15.

As illustrated inFIG. 4, the substrate15includes a substrate body151. Electronic parts are mounted on the substrate body151, and a soldering portion152protrudes from the rear surface of the substrate body151. The second connecting portion122aand the third connecting portion124aare each disposed inside an outermost line OL indicating the outermost part of the soldering portion152which is the terminal electrode disposed on the rear surface of the substrate15. With this configuration, when the substrate15is distorted with the distortion of the motherboard, it is possible to prevent stress due to influence of the distortion from being transmitted to the second connecting portion122aand the third connecting portion124a.

REFERENCE SIGNS LIST