JP2005135962A - Shield structure of electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shield structure of an electronic apparatus having a simple structure and displaying certain shielding ability. <P>SOLUTION: Integrally formed shield cases 11 and 12 have a rib 13 with continuous structure around it. The shield cases are fitted to a wiring board 10 through a conductive tape 21 stuck to an upper face of the rib. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a shield structure that shields a radio circuit of an electronic device such as a communication device from electromagnetic noise.

  A radio circuit or the like of a communication device is easily affected by electromagnetic waves, and malfunctions are caused by electromagnetic noise entering from the outside or electromagnetic noise generated from a power supply unit or the like inside the communication device. For this reason, a radio circuit or the like is housed in a shield case in order to prevent electromagnetic noise from entering.

  For example, in the shield structure of an electronic device disclosed in Patent Document 1, a portion of the wiring board that needs to be shielded is covered with a shield case. As shown in FIG. 11, the shield case 1 is attached so as to cover a required portion of the wiring board 2, and the shield case 1 has a box shape with the board side surface open. A mounting claw 3 is formed, and a notch 5 is formed at a position corresponding to the mounting claw 3 of the wiring board 2.

  The shield case 1 is attached to the wiring board 2 by the attachment claw 3 being hooked on the notch 5. A contact 4 is provided between the mounting case 3 and 3 of the shield case 1 so as to contact the ground line of the wiring board 2.

  In the shield structure of the conventional electronic device described above, the shield case 1 and the ground line of the wiring board 2 are basically in point contact, and the attachment claw 3 and the attachment claw 3 are securely connected between the attachment claw 3 and the contact 4. It may be said that the substrate is not in contact with the ground line, and the substrate may be warped due to the change of the substrate over time. In this case, a gap is generated between the shield case 1 and the wiring substrate 2, and There is a risk of noise intrusion.

  Although it is conceivable that the shield structure is a double shield case, there is a problem that the manufacturing cost increases. Further, in the shield structure of the conventional electronic device, it is necessary to provide a shield case at each place where the shield is necessary, and a plurality of shield cases are required on the same wiring board 2, which causes a cost increase.

JP 2000-286484 A

  In view of such circumstances, the present invention provides a shield structure for an electronic device that exhibits a reliable shield performance with a simple structure.

  The present invention relates to a shield structure for an electronic device in which an integrally formed shield case has at least a continuous rib around the rib, and the shield case is attached to a wiring board via a conductive tape attached to the upper surface of the rib. Is.

  According to the present invention, the integrally formed shield case has at least a continuous rib, and the shield case is attached to the wiring board via the conductive tape attached to the upper surface of the rib. Since it is electrically connected to the ground of the wiring board around the entire circumference and no gap is formed between the wiring board and the shield case by the conductive tape, an excellent effect such as a reliable shielding effect is exhibited.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  First, a first embodiment of the present invention will be described with reference to FIGS.

  In the figure, 10 is a wiring board, 11 is a base-side shield case, and 12 is a cover-side shield case.

  The base side shield case 11 and the cover side shield case 12 have substantially the same structure.

  The base shield case 11 will be described.

  The base-side shield case 11 is made of aluminum, and is integrally formed by a die casting method or the like. The base-side shield case 11 surrounds the periphery and is continuous around the entire periphery. The rib 15 forms the required number of box-like spaces 16 with the substrate side open.

  Screw holes 17 are formed in the intersecting portions where the peripheral ribs 13 and the vertical ribs 14, the peripheral ribs 13 and the horizontal ribs 15, and the vertical ribs 14 and the horizontal ribs 15 intersect with each other. Projections 18 are formed at four positions, in the figure, at the corners, and screw holes 19 are also formed in the protrusions 18.

  The cover-side shield case 12 has substantially the same structure as the base-side shield case 11 except that it does not have the protruding portion 18, and a description thereof will be omitted.

  The base-side shield case 11 and the cover-side shield case 12 are attached so as to sandwich the wiring board 10.

  First, a strip-shaped conductive tape 21 shown in FIG. 4A is attached to the upper surfaces of the peripheral rib 13, the vertical rib 14, and the horizontal rib 15 of the base-side shield case 11. The peripheral ribs 13, the vertical ribs 14, the horizontal ribs 15 and the conductive tape 21 may be adhered by an adhesive, preferably a conductive adhesive tape is attached in advance to the back surface of the conductive tape 21, It adheres with this conductive adhesive tape. The conductive tape 21 is cut in advance to the pasting length, or a piece cut to a predetermined dimension is added as appropriate, or cut appropriately.

  The conductive tape 21 is made of a plastic foam as a core material and coated with a conductive material such as a nickel-plated polyester fiber or the like on the core material, and is soft and easy to adjust to the shape of the adhesive surface. It has the property that it can be cut easily and can be easily punched.

  A strip-shaped conductive tape (not shown) is attached to the upper surfaces of the peripheral ribs, vertical ribs, and horizontal ribs of the cover-side shield case 12.

  The wiring board 10 is overlaid on the base-side shield case 11, and a screw 22 is inserted through the wiring board 10 and screwed to the protrusion 18. The wiring board 10 is attached to the base-side shield case 11 via the conductive tape 21. Although not shown, a ground pattern is formed on the portion of the wiring board 10 where the conductive tape 21 abuts, and the base shield case 11 contacts the ground pattern via the conductive tape 21.

  Next, the cover-side shield case 12 is overlaid on the wiring board 10, the screw 23 is inserted through the cover-side shield case 12 and the wiring board 10, and is screwed to the intersection of the base-side shield case 11. The cover side shield case 12 and the wiring board 10 are fastened together with the base side shield case 11 by the screw 23.

  As described above, the strip-shaped conductive tape is also affixed to the peripheral rib, the vertical rib, and the horizontal rib of the cover-side shield case 12, and the ground pattern is also formed on the cover-side shield case 12 side of the wiring board 10. The conductive tape is in contact with the ground pattern. Note that the ground patterns formed on both surfaces of the wiring board are appropriately conducted through through holes.

  The conductive tape 21 is flexible and conforms to the contact surface. Further, by tightening the screw 23, the base-side shield case 11 and the wiring board 10 are sealed, and the wiring board 10 and the cover-side shield case 12 are sealed. In addition, it is electrically connected to the ground pattern of the wiring board 10 over the entire length of the peripheral rib, the vertical rib, and the horizontal rib.

  Thus, the space 16 formed in each of the base side shield case 11 and the cover side shield case 12 is individually and mutually shielded. Further, the base-side shield case 11 and the cover-side shield case 12 serve as a reinforcing member for the wiring board 10 and prevent the substrate from changing with time.

  The operation of attaching the conductive tape 21 is performed on the upper surfaces of the peripheral ribs, the vertical ribs, and the horizontal ribs, and may be in contact with the ground pattern of the wiring board 10 in an assembled state. Therefore, even if the conductive tape 21 protrudes to the outside of the base-side shield case 11, there is no problem in performance, and the attaching operation does not require high accuracy and skill.

  Note that positioning protrusions may be provided on the base-side shield case 11 and the cover-side shield case 12 as a configuration that facilitates positioning of the conductive tape 21 when the conductive tape 21 is attached.

  For example, as shown in FIGS. 2 and 3, a U-shaped protrusion 25 is provided at the intersection 24 of the vertical rib 14 and the horizontal rib 15. The protrusion 25 has a linear bulge continuous in a U-shape, and has a height at which the conductive tape 21 can be sufficiently compressed and deformed.

  By providing the protrusion 25, when the conductive tape 21 is pasted, the position in the longitudinal direction and the width direction of the tip is easily determined, and workability is improved. In addition, by providing the protrusion 25 and positioning the tip, the conductive tape 21 is in shortage at the intersecting portion 24, but the conductive material previously punched in accordance with the shape of the intersecting portion 24 is used. The adhesive tape 21a (see FIG. 4B to FIG. 4D) is attached to the intersection 24.

  FIG. 5 shows a state in which the conductive tape 21 and the conductive tape 21a are attached to the peripheral rib 13, the vertical rib 14, the horizontal rib 15, and the intersecting portion 24, respectively.

  Various shapes of protrusions for positioning the conductive tape 21 are conceivable. As shown in FIGS. 6 and 7, the protrusions simply linearly cross the peripheral ribs 13, the vertical ribs 14, and the horizontal ribs 15. 26 may be used. The protrusion 26 positions the tip of the conductive tape 21. The positioning of the conductive tape 21 in the width direction can be performed with reference to the edges of the peripheral ribs 13, the vertical ribs 14, and the horizontal ribs 15, so that there is no problem in the work.

  Although not particularly shown, the intersecting portion 24 may be made higher than the upper surfaces of the peripheral rib 13, the vertical rib 14, and the lateral rib 15, and the entire intersecting portion 24 may be a projection. In this case, a recess 24a may be formed as shown in FIGS.

  FIG. 10 shows a case where dot-like protrusions 27 are formed on the upper surfaces of the peripheral rib 13, the vertical rib 14, and the horizontal rib 15 at a required pitch. By forming the protrusions 27, the protrusions 27 are bitten into the conductive tape 21, the conduction state between the protrusions 27 and the conductive tape 21 is improved, and the electronic device vibrates. In this case, the displacement of the conductive tape 21 is suppressed.

  Next, the relationship between the protrusion 25, the protrusion 26, and the protrusion 27 and the wiring substrate 10 is such that the wiring substrate 10 and the protrusion 25, the protrusion 26, and the protrusion 27 are in contact with each other with the conductive tape 21 incorporated. Alternatively, the wiring board 10 and the protrusions 25, 26, and 27 may be in contact with each other. Further, a hole is formed in the conductive tape 21 so that the protrusion 25, protrusion 26, and protrusion 27 are in direct contact with the ground pattern on the substrate side, and conduction is obtained at the protrusion 25, protrusion 26, and protrusion 27 portions. You may do it. Further, in order to prevent the wiring board 10 and the protrusions 25, 26, and 27 from contacting each other, the protrusion 25, the protrusion 26, and the protrusion 27 are connected to the conductive tape 21 and the conductive tape 21a as described above. When the height is set so as not to come into contact with the wiring board 10 even when compressed, or in some cases, recesses, cutouts, etc. are formed at positions facing the projections 25, 26, 27 on the wiring board 10 side. is there. When the relief is formed, when the conductive tape 21 and the conductive tape 21a provide sufficient conduction between the wiring board 10 and the base-side shield case 11 and the cover-side shield case 12, the protrusions 25, the protrusion 26, and the protrusion 27 have an effect of preventing a local load from being generated at a portion facing the protrusion 26 and the protrusion 27.

  In the embodiment described above, the shield cases are provided on both surfaces of the wiring substrate 10, but the shield cases may be provided on either one of the surfaces. Further, although the inside of the shield case is partitioned by the vertical rib 14 and the horizontal rib 15, the space 16 may be formed by the shield case alone.

It is a perspective view which shows embodiment of this invention. It is a perspective view of the shield case in this embodiment. It is the A section enlarged view of FIG. (A) (B) (C) (D) is explanatory drawing of the electroconductive tape used for this embodiment. It is explanatory drawing which shows the relationship between the shield case and electroconductive tape in this embodiment. It is explanatory drawing which shows other embodiment of this invention. It is the B section enlarged view of FIG. It is explanatory drawing which shows the other example of the projection part in this invention. It is explanatory drawing which shows the other example of the projection part in this invention. It is explanatory drawing which shows the further another example of the projection part in this invention. It is explanatory drawing of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wiring board 11 Base side shield case 12 Cover side shield case 13 Peripheral rib 14 Vertical rib 15 Horizontal rib 16 Space 21 Conductive tape 24 Intersection 25 Projection 26 Projection 27 Projection

Claims (1)

  A shield structure for an electronic device, wherein the integrally formed shield case has at least a continuous rib around the periphery, and the shield case is attached to a wiring board via a conductive tape attached to the upper surface of the rib.

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