Overmolded PC board with ESD protection and EMI suppression

• US 5,677,511 A
• Filed: 03/20/1995
• Issued: 10/14/1997
• Est. Priority Date: 03/20/1995
• Status: Expired due to Term

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Taylor, Carl James, Patterson, Michael William
• Primary Examiner(s): Ledynh, Bot L.
• Application Number:
  US08/406,450
• Time in Patent Office: 939 Days
• Field of Search: 174/52.1-52.4, 257/787-790, 257/795, 361/737-739, 361/749, 361/760, 361/816, 361/820, 361/818, 439/607-610
• US Class Current: 174/527
• CPC Class Codes: G06F 13/409 Mechanical coupling back panels H05K7/1438
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H05K 3/284 for encapsulating mounted components H05K1/185 takes precedence
• CPC Class Codes: H05K 5/0208 Interlock mechanisms; Means for avoiding unauthorised use or function, e.g. tamperproof
• CPC Class Codes: H05K 5/0269 Card housings therefor, e.g. covers, frames, PCB

Abstract

An apparatus directed to portable peripheral cards is disclosed which provides protection against electro-static discharge and electro-magnetic interference. Furthermore, this apparatus provides a solid housing which affords a strong protective structure for the PC board and also protects the ICs housed inside the peripheral card from being easily accessed.

Claims

1. A portable peripheral card comprising:

a printed circuit board (PC board) having an active region where one or more electrical components are mounted;

an electrical connector attached to the PC board, whereby external devices electrically access said one or more electronic components via said electrical connector;

a solid package encapsulating the PC board yet leaving a portion of said electrical connector exposed, said solid package being composed of a conductive segment and a non-conductive segment, wherein said non-conductive segment encapsulates said active region of the PC board, and said conductive segment encapsulates a remaining outer perimeter of the PC board surrounding said active region; and

a conductive layer overlaying said solid package such that said conductive layer substantially covers the area over said non-conductive segment and further extends over said conductive segment.

2. A portable peripheral card as recited in claim 1 wherein said conductive segment is from metal and said non-conductive segment is from polymer.

3. A portable peripheral card as recited in claim 2 wherein said polymer is thermoset plastic material.

4. A portable peripheral card as recited in claim 2 wherein said metal is pre-fabricated and is clamped to the PC board.

5. A portable peripheral card as recited in claim 1 wherein said conductive segment is filled polymer and said non-conductive segment is polymer.

6. A portable peripheral card as recited in claim 5 wherein a conductive trace travels around said outer perimeter of the PC board and electrically contacts said electrical connector.

7. A portable peripheral card as recited in claim 6 wherein said conductive trace is a ground trace.

8. A portable peripheral card as recited in claim 1 wherein said conductive segment is from thermoplastic material and said non-conductive segment is from thermoset plastic material.

9. A portable peripheral card as recited in claim 1 wherein said conductive layer is secured to said solid package via a conductive adhesive.

10. A portable peripheral card as recited in claim 9 wherein said conductive adhesive is z-axis adhesive.

11. A portable peripheral card as recited in claim 1 wherein said conductive layer is a sheet of metal.

12. A portable peripheral card as recited in claim 1 wherein said peripheral card is a PCMCIA card.

13. A portable peripheral card comprising:

a printed circuit board (PC board) having an active region where one or more electrical components are mounted;

an electrical connector attached to the PC board, whereby external devices electrically access said one or more electronic components via said electrical connector;

a solid package encapsulating the PC board yet leaving a portion of said electrical connector exposed, said solid package being composed of a conductive segment and a non-conductive segment, wherein said non-conductive segment encapsulates said active region of the PC board, and said conductive segment encapsulates a remaining outer perimeter of the PC board surrounding said active region; and

a conductive trace that travels around said outer perimeter of the PC board and electrically contacts said electrical connector.

14. A portable peripheral card as recited in claim 13 wherein said conductive trace is a ground trace.

15. A portable peripheral card as recited in claim 14 further comprising a conductive layer overlaying said solid package such that said conductive layer substantially covers the area over said non-conductive segment and further extends over said conductive segment.