Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K9/00—Screening of apparatus or components against electric or magnetic fields
  • H05K9/0007—Casings
  • H05K9/002—Casings with localised screening
  • H05K9/0022—Casings with localised screening of components mounted on printed circuit boards [PCB]
  • H05K9/0024—Shield cases mounted on a PCB, e.g. cans or caps or conformal shields
  • H05K9/0032—Shield cases mounted on a PCB, e.g. cans or caps or conformal shields having multiple parts, e.g. frames mating with lids

Definitions

• the present invention relates to a shielding device for preventing electromagnetic interference (EMI), and more particularly, to a shielding device adapted to providing EMI shielding for one or more electric components on a substrate.
• EMI electromagnetic interference
• a shielding case/device may be used to shield electronic/electrical components from EMI.
• One usual conventional shielding device is of a two-piece structure wherein a cover is mounted to a frame.
• Another usual conventional shielding device is of a one-piece structure, i.e., the shielding device consists of one component.
• a conventional shielding case is usually fixed on a printed circuit board (PCB) through SMT welding.
• PCB printed circuit board
• electronic elements e.g., IC parts or the like
• the maintainer will have to break the welding joints so as to remove the shielding case, thus the electronic elements surrounded by the shielding device are very likely to be damaged, and the maintenance is also very inconvenient.
• the frame is welded onto the PCB, and the cover is mounted onto the frame, thus a mounting structure between the cover and the frame is very firm, which prevents the cover from dropping off the frame accidentally; when a maintenance is carried out, the cover should be removed with a large external force, and remounted after the maintenance is finished, so the electronic elements are likely to be damaged when the cover is removed from the frame.
• the frame may present an obstacle to maintenance. In addition, it is inconvenient to maintain such a structure.
• an internal elastic shielding sheet and an external metal drawing part are generally connected to each other via a laser welding method.
• the welding quality affects the shielding performance significantly, thus the performance of the fabricated shielding device tends to be degraded or destabilized; besides, the fabricating process is complicated, and the production efficiency and yield are also low.
• the aim of the present invention is to provide a shielding device that overcomes the defects of the current shielding device, and facilitate dismounting so as to conveniently maintain electronic elements surrounded by the shielding device.
• One embodiment of the present invention provides a shielding device for shielding at least one electronic element disposed on a PCB.
• the shielding device has a frame and a shielding case engaging with the frame and electrically connected thereto.
• the lower side of the frame is provided with elastic sheets that elastically and electrically contact a welding-pad on the PCB, and the frame is further provided with a first mounting hole that is aligned with screw holes on the PCB and allow screws to pass therethrough.
• the shielding case is provided with a second mounting hole that is aligned with the first mounting hole and allows the screw to pass therethrough. The screw is sequentially passed through the second mounting hole and the first mounting hole, and is threaded into the screw hole on the PCB so as to fix the shielding case and the frame onto the PCB.
• the present invention fixes the shielding device onto the PCB via a method other than welding, and the shielding case and the frame are also fixed to each other by same screws.
• the shielding case and the frame are also fixed to each other by same screws.
• the present invention As compared with a current shielding device of a one-piece or two-piece structure, the present invention needs no SMT welding, resulting in cost and energy saving. Besides, as compared with the current conventional shielding devices, the present invention presents a firm structure, which improves the performance of the PCB in drop tests and torsion tests. In addition, it not necessary in the present invention to weld the frame and the shielding case of the shielding device, thus the process is simple and reliable, and the production efficiency and yield are also high.
• a snap slot is provided on one of the frame and the shielding case, and an engaging convex portion that is to be engaged with the snap slot is provided on the corresponding position of the other one of the frame and the shielding case.
• an engaging structure can enhance the connection between the frame and the shielding case, and facilitate mounting.
• an internal side of the snap slot is provided with engaging contact bump, while the engaging convex portion is provided with engaging hole or engaging concave portion to be engaged with the engaging contact bump.
• the snap slot or the engaging convex portion may be disposed on a peripheral wall of the frame or the shielding case, i.e., the snap slot is disposed on the peripheral wall of one of the frame and the shielding case, and the engaging convex portion is disposed correspondingly on a peripheral wall of the other one of the frame and the shielding case.
• engaging structures may also be disposed at a position interior of the peripheral walls of the frame and the shielding case, i.e., the snap slot is disposed at a position interior of the peripheral wall of one of the frame and the shielding case, and the engaging convex portion is disposed correspondingly on the other one of the frame and the shielding case.
• a plurality of snap slots are disposed at the position interior of the peripheral wall of one of the frame and the shielding case, and the snap slots are disposed to separate a region surrounded or covered by one of the frame and the shielding case into a plurality of separated sections, and hence a shielding device may be used to shield a plurality of electronic elements separately.
• an external wall of the shielding case is formed as part of the engaging convex portion, so that the structure can be further simplified.
• the snap slot is configured in an approximate U-shape, or in a right-angled frame shape with one side open.
• the engaging contact bump is disposed on internal sides of two side walls opposing each other of the snap slot.
• a peripheral portion of the engaging contact bump has a guiding bevel or guiding arc to facilitate engagement with and disengagement from the engaging hole or the engaging concave portion, so that the frame and the shielding case can be connected to and separated from each other easily.
• the peripheral portion of the engaging contact bump is provided with an engaging locking portion to facilitate engagement lock with the engaging hole or engaging concave portion and prevent disengagement, so that the frame and the shielding case are more firmly connected to each other.
• the external wall of the shielding case is formed as part of the engaging convex portion, an edge portion of the external wall extends outward from the snap slot by a predetermined length, so that the edge portion of the external wall extending beyond the snap slot can act as a holding portion in separating the frame from the shielding case, and the engaging contact bump can be disengaged from the engaging hole or the engaging concave portion by holding and pressing the edge portion of the external wall.
• the elastic sheet of the frame is formed by punching from the lower side of the frame, so that one side of the elastic sheet is connected to the lower side of the frame to form a connecting base end, while other three sides detach from the lower side of the frame so as to form a free end, which elastically extends downward with respect to the lower side of the frame.
• the elastic sheet may be fabricated integrally with the frame, therefore material is saved, structural strength is improved, and the fabricating process is simplified.
• the frame is provided with a snap slot opening upward to engage with the engaging convex portion on the shielding case, and the elastic sheet is formed at the lower side of the snap slot. The snap slot and the elastic sheet are disposed at the corresponding positions in upward/downward directions, so that the structure of the frame is more compact and the material is saved.
• protruding sheets are disposed on the frame and the shielding case, and extend outward from peripheral walls thereof.
• the first mounting hole and the second mounting hole are disposed on the protruding sheets respectively, which is convenient for mounting and removing the shielding device without any impedance.
• the protruding sheets are formed at respective corners of the frame and the shielding case configured in a rectangular shape.
• the protruding sheets can be disposed at positions of the frame and the shielding case which are interior of the peripheral walls thereof and shunt the shielded electronic elements, and the first mounting hole and the second mounting hole are disposed on the protruding sheets respectively.
• the frame and the shielding case can be fixed more firmly on the PCB by disposing additional protruding sheets at positions outside the peripheral walls that pose no impedance.
• Fig. 1 is an exploded perspective view showing a shielding device according to an embodiment of the invention to be mounted onto a PCB;
• Fig. 2 is an exploded perspective view showing a frame and a shielding case in a shielding device according to an embodiment of the invention.
• Figs. 3a ⁇ 3e are structural diagrams showing the assembled frame and shielding case in a shielding device according to an embodiment of the invention, wherein Fig. 3a is a front view, Fig. 3b is a left view, Fig. 3c is a right view, Fig. 3d is a top view, and Fig. 3e is a bottom view, respectively, of the assembled state.
• Figs. 4a ⁇ 4e are structural diagrams indicative of a frame in a shielding device according to an embodiment of the invention, wherein Fig. 4a is a front view, Fig. 4b is a left view, Fig. 4c is a right view, Fig. 4d is a top view, and Fig. 4e is a bottom view, respectively, of the frame.
• Fig. 5 is an amplified diagram showing an example of elastic sheets on a frame according to the present invention.
• Fig. 6 is a partially amplified structural diagram showing a snap slot and engaging contact bumps disposed thereon.
• Fig. 7 is a structural diagram showing an example of a snap slot according to the present invention.
• Figs. 8a ⁇ 8e are structural diagrams showing a shielding case of a shielding device in one embodiment of the present invention, wherein Fig. 8a is a front view, Fig. 8b is a left view, Fig. 8c is a right view, Fig. 8d is a top view, and Fig. 8e is a bottom view, respectively, of the shielding case.
• Fig. 9 is a structural diagram showing an external wall of a shielding case which constitutes part of the engaging bumps in one embodiment of the present invention.
• articles “a”, “an”, “the” and “said” mean one or more such components or features, while terms “including”, “comprising” and “having” have an inclusive meaning, and there may be additional elements or features besides those having been mentioned.
• a shielding device 1 for shielding at least one electronic element 13 disposed on a PCB 10, as shown in Fig. 1.
• the shielding device 1 has a frame 2 and a shielding case 3 engaging with the frame 2 and electrically connected thereto.
• the lower side of the frame 2 is provided with elastic sheets 24 that elastically and electrically contact a welding-pad 11 arranged on the PCB 10 (see Fig. 5), and the frame 2 is further provided with first mounting holes 23 that are aligned with screw holes 12 arranged on the PCB 10 and allow screws 4 to pass therethrough.
• the shielding case 3 is provided with second mounting holes 32 that are aligned with the first mounting holes 23 and allow the screws 4 to pass therethrough.
• the shielding case 3 and the frame 2 are fixed onto the PCB 10 by sequentially passing screws 4 through the second mounting holes 32 and the first mounting holes 23, and by threading these screws into the screw holes 12 on the PCB 10.
• the present invention fixes the shielding device 1 onto the PCB 10 via a fixing method other than welding, and the shielding case 3 and the frame 2 are also fixed to each other by same screws 4.
• the shielding case 3 and the frame 2 are also fixed to each other by same screws 4.
• it only needs to loosen the screws 4 when the electronic element 13 in the shielding device 1 is to be maintained, and the shielding case 3 and the frame 2 can be removed from the PCB 10 simultaneously.
• re-welding and re-assembly are dispensed.
• the frame 2 shielding device 1
• the frame 2 is electrically connected to the PCB 10 at the same time when the frame 2 and the shielding case 3 are mounted on the PCB 10 with the screws 4, without welding the frame 2 onto the PCB 10, as in the case of prior art shielding devices.
• a snap slot 21 is provided on one of the frame 2 and the shielding case 3 (e.g., the frame 2), and an engaging convex portion 35 that is to engage with the snap slot 21 is provided on corresponding position of the other one of the frame 2 and the shielding case 3 (e.g., the shielding case 3).
• an engaging arrangement can enhance the connection between the frame 2 and the shielding case 3, and hence facilitate mounting.
• the snap slot 21 is provided on the frame 2 and the engaging convex portion 35 is provided on the shielding case 3, it is easy for persons skilled in the art to contemplate other arrangements, e.g.
• the snap slot 21 or the engaging convex portion 35 can be disposed on a peripheral wall of the frame 2 or the shielding case 3, i.e., the snap slot 21 is disposed on a peripheral wall 25 of one of the frame 2 and the shielding case 3 (e.g., the frame 2), and the engaging convex portion 35 is disposed correspondingly on a peripheral wall 36 of the other one of the frame 2 and the shielding case 3 (e.g., the shielding case 3).
• the frame 2 or the shielding case 3 can be firmly jointed with a small joining structure by means of an engagement between the snap slot 21 and the engaging convex portion 35.
• engaging structures can also be disposed in a part interior of the peripheral walls 25 and 36 of the frame 2 and the shielding case 3, i.e., the snap slot 21 is disposed on a part interior of the peripheral wall 25 of one of the frame 2 and the shielding case 3 (e.g., the frame 2), and the engaging convex portion 35 is disposed correspondingly on the other one of the frame 2 and the shielding case 3 (e.g., the shielding case 3).
• the snap slot 21 and the engaging convex portion 35 can be set in a single pair, or in a plurality of pairs.
• a plurality of snap slots 21 are disposed on the part interior of the peripheral wall 25 of the frame 2, and they separate a region surrounded or covered by the frame 2 into a plurality of separated sections; correspondingly, the engaging convex portions 35 on the part interior of the peripheral wall 36 of the shielding case 3 are also disposed to separate a region surrounded or covered by the shielding case 3 into a plurality of separated sections.
• the snap slots 21 and the engaging convex portions 35 can engage with each other correspondingly, thus one shielding device 1 can act to shield a plurality of electronic elements 13 separately.
• an external wall 33 of the shielding case 3 forms as part of the engaging convex portion 35, so that the structure can be further simplified.
• engaging holes 34 may be disposed on the external wall 33.
• an internal side of the snap slot 21 is provided with engaging contact bumps 211
• the engaging convex portion 35 is provided with engaging holes 34 or engaging concave portions to engage with the engaging contact bumps 211.
• the engaging contact bumps 211 can be formed as bumps that are directly disposed on the internal side of the snap slot 21 , e.g., formed by protrusions welded on the internal side of the snap slot 21.
• the engaging contact bumps 211 can be formed by protruding part of the internal side inward by pressing the external side of the snap slot 21 toward the internal side.
• the engaging holes 34 may be formed by punching side walls of the engaging convex portion 35, or engaging concave portions (not shown in the drawings) may be formed by pressing the side walls of the engaging convex portion 35 to produce concave structures.
• the snap slot 21 is configured in an approximate U-shape, or in a right-angled frame shape with one side open.
• the engaging contact bumps 211 are disposed on internal sides of two side walls opposing each other of the snap slot 21 , as shown in Fig. 6.
• a peripheral portion 212 of the engaging contact bump 211 has a guiding bevel or guiding arc to facilitate engagement with and disengagement from the engaging hole 34 or the engaging concave portion, so that the frame 2 and the shielding case 3 can be connected to and separated from each other easily.
• the peripheral portion 212 of the engaging contact bump 211 is provided with an engaging locking portion to facilitate engagement lock with the engaging hole or engaging concave portion and prevent disengagement.
• a relatively large angle forms between the surface of the engaging locking portion and the internal side of the snap slot 21 , so that it is difficult for edges of the engaging holes 34 to slide off or drop from the peripheral portion 212 of the engaging contact bump 211 under a normal force application, and hence the frame 2 and the shielding case 3 are connected more firmly to each other.
• the external wall 33 of the shielding case 3 is preferably formed as part of the engaging convex portion 35, and an edge portion of the external wall 33 extends outward from the snap slot 21 by a predetermined length.
• the edge portion of the external wall 33 extending beyond the snap slot can act as a holding portion in separating the frame 2 from the shielding case 3, and the engaging contact bump 211 can be disengaged from the engaging hole 34 or the engaging concave portion by holding and pressing the edge portion of the external wall.
• the elastic sheet 24 of the frame 2 is formed by punching from the lower side of the frame 2, so that one side of the elastic sheet 24 is connected to the lower side of the frame so as to form a connecting base end 242, while other three sides detach from the lower side of the frame so as to form a free end 241 , which elastically extends downward with respect to the lower side of the frame 2.
• the elastic sheet 24 may be fabricated integrally with the frame 2, therefore material is saved, structural strength is improved and the fabricating process is simplified.
• the frame 2 is provided with a snap slot 21 opening upward to engage with the engaging convex portion 35 on the shielding case 3, and the elastic sheet 24 is formed at the lower side of the snap slot 21 , as shown in Fig. 7.
• the snap slot 21 and the elastic sheet 24 are disposed at the corresponding positions in upward/downward directions, so that the structure of the frame 2 is more compact and the material is saved.
• protruding sheets 22, 31 are disposed on the frame 2 and the shielding case 3, and extend outward from peripheral walls thereof.
• the first mounting holes 23 and the second mounting holes 32 are disposed on the protruding sheets 22, 31 , thus the shielding device may be conveniently mounted and dismounted, without any impedance.
• the protruding sheets 22, 31 are formed at respective corners of the frame 2 and the shielding case 3 configured in a rectangular shape.
• these protruding sheets can be disposed at other appropriate positions of the frame 2 and the shielding case 3.
• the protruding sheets can be disposed at positions of the frame 2 and the shielding case 3 which are interior of the peripheral walls thereof and shunt the shielded electronic elements, and the first mounting holes 23 and the second mounting holes 32 are disposed on the protruding sheets.
• the frame and the shielding case can be fixed more firmly on the PCB by disposing additional protruding sheets at positions outside the peripheral walls that pose no impedance.

Landscapes

• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40281020

Family Applications (1)

Country Status (2)

Families Citing this family (6)

Citations (4)

Family Cites Families (1)

• 2007
  • 2007-07-25 CN CN2007101307924A patent/CN101355867B/zh active Active
• 2008
  • 2008-07-25 WO PCT/CN2008/071761 patent/WO2009012723A1/en active Application Filing

Patent Citations (4)

Also Published As

Similar Documents

Legal Events