Methods and apparatus for EMI shielding

Abstract

Disclosed are methods and apparatus for improving the resiliency and airflow through a honeycomb air vent filter while providing EMI shielding. In one embodiment, the honeycomb can be manufactured from a dielectric (e.g., plastic) substrate to provide improved resistance to deformation as compared to conventional aluminum honeycomb. The dielectric honeycomb substrate is metallized to provide EMI shielding capability. The metallized honeycomb substrate is cut slightly oversize to fit an opening in an electronic enclosure, which results in elastic deformation of resilient perimeter spring fingers that are used to hold the metallized dielectric honeycomb in place and provide electrical conductivity between the metallized dielectric substrate and the enclosure, thereby eliminating the use of a frame. In another embodiment, additional conductive layers can be added to the metallized dielectric honeycomb. In yet another embodiment, the metallized dielectric honeycomb substrate can be utilized in a framed configuration to provide improved durability.

1. A frameless vent panel adapted to shield against electromagnetic interference (EMI) comprising:
 a dielectric panel having a thickness defined by a first side and a second side, and defining a plurality of apertures, said dielectric panel further having a perimeter;   a first electrically conductive layer applied to the dielectric pane, wherein the conductively coated dielectric panel attenuates a transfer of electromagnetic energy from the first side to the second side of the substrate; and   a strip of compressible conductive foam material, said strip having a width substantially equal to the thickness of said dielectric panel and being wrapped around the perimeter thereof and substantially covering said thickness between said first side and said second side.   
     
     
       2. The frameless vent panel of  claim 1 , wherein the dielectric panel is of a polymer. 
     
     
       3. The frameless vent panel of  claim 1 , wherein the dielectric panel is of a material selected from the group consisting of polycarbonate, polypropyle , acrylonitrile-butadiene-styrene (ABS), polyethylene, polyvinyl chloride (PVC), carbon, fiberglass, paper and combinations thereof. 
     
     
       4. The frameless vent panel of  claim 1 , wherein the dielectric panel comprises a plurality of tubes bonded together. 
     
     
       5. The frameless vent panel of  claim 1 , wherein the dielectric panel comprises a plurality of tubes co-extruded together. 
     
     
       6. The frameless vent panel of  claim 1 , wherein the dielectric panel is produced using an injection molding process. 
     
     
       7. The frameless vent panel of  claim 1 , wherein the dielectric panel comprises a plurality of corrugated dielectric sheets bonded together, wherein the bonded corrugated dielectric sheets define the plurality of apertures. 
     
     
       8. The frameless vent panel of  claim 1 , wherein the electrically conductive layer is of a material selected from the group consisting of copper, nickel, tin, aluminum, silver, gold, graphite, lead, palladium, cadmium, zinc and combination thereof. 
     
     
       9. The frameless vent panel of  claim 1 , further comprising a second electrically conductive layer in electrical communication with the first electrically conductive layer. 
     
     
       10. The frameless vent panel of  claim 1 , wherein the plurality of apertures is configured as a two-dimensional array of like apertures. 
     
     
       11. The frameless vent panel of  claim 10 , wherein a cross-sectional shape of each of the like apertures is a shape selected from the group consisting of circular, elliptical, hexagonal, square, rectangular, triangular, rhomboidal, and combinations thereof. 
     
     
       12. The frameless vent panel of  claim 1 , wherein a cross-sectional diameter of each of the like apertures is selected to be between about 0.06 inches and 1 inch. 
     
     
       13. The frameless vent panel of  claim 1 , wherein the dielectric panel is selected to have a density of between about 2 lb/ft 3  and about 20 lb/ft 3 . 
     
     
       14. The frameless vent panel of  claim 1 , wherein the vent panel provides at least about 20 dB of attenuation to EMI at 10 9  Hz. 
     
     
       15. The frameless vent panel of  claim 1 , wherein said strip compressible conductive foam is secured to said dielectric panel with an adhesive. 
     
     
       16. The frameless vent panel of  claim 1 , wherein said strip of compressible conductive foam has a thickness in a range from about 0.5 millimeter to about 10 millimeters. 
     
     
       17. A frameless vent panel for providing electromagnetic interference (EMI) shielding for a ventilation opening of an electronic enclosure, the frameless vent panel comprising:
 a dielectric panel having a thickness defined by a first side and a second side, a perimeter, and a plurality of apertures extending from the first side to the second side for allowing airflow therethrough;   at least one electrically-conductive material provided to the dielectric panel for attenuating a transfer of electromagnetic energy from the first side to the second side; and   a resiliently compressible electrically-conductive edge substantially about the perimeter of the frameless vent panel and substantially covering said thickness between said first side and said second side, for compressively fitting the frameless vent panel within the ventilation opening in electrical communication with the electronic enclosure.   
     
     
       18. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge is configured for allowing the frameless vent panel to be compressively fit and retained within the ventilation opening without using any mechanical fasteners. 
     
     
       19. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge is configured for allowing the frameless vent panel to be compressively fit and retained within the ventilation opening in a direction normal to the longitudinal axes of the apertures. 
     
     
       20. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises a band of one or more materials, the band having a width substantially equal to the thickness of the dielectric panel and being wrapped around the perimeter of the dielectric panel such that the band substantially covers the thickness defined between the first side and the second side. 
     
     
       21. The frameless vent panel of claim 20, wherein the band of one or more materials comprises at least one or more of electrically-conductive foam, electrically-conductive fabric, and electrically-conductive fabric wrapped over foam. 
     
     
       22. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive fabric. 
     
     
       23. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive fabric wrapped over foam. 
     
     
       24. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive foam. 
     
     
       25. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises a resiliently compressible EMI gasket having a width substantially equal to the thickness of the dielectric panel, the resiliently compressible EMI gasket being wrapped around the perimeter of the dielectric panel such that the resiliently compressible EMI gasket substantially covers the thickness defined between the first side and the second side. 
     
     
       26. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive elastomer. 
     
     
       27. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive protrusions extending outwardly substantially about the perimeter. 
     
     
       28. The frameless vent panel of claim 27, wherein the electrically-conductive protrusions comprise at least one or more of a resilient spring finger, a dimple, or a combination thereof. 
     
     
       29. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive wire mesh. 
     
     
       30. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive material disposed over a resiliently compressible member. 
     
     
       31. The frameless vent panel of claim 17, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive fabric applied to an elastomer. 
     
     
       32. The frameless vent panel of claim 17, wherein the openings have a honeycomb configuration. 
     
     
       33. The frameless vent panel of claim 17, further comprising flame retardant provided to the conductively coated dielectric panel for achieving a flame rating of V0 under Underwriter's Laboratories (UL) Standard No. 94. 
     
     
       34. The frameless vent panel of claim 17, further comprising a corrosion inhibitor provided to the conductively coated dielectric panel. 
     
     
       35. A frameless vent panel for providing electromagnetic interference (EMI) shielding for a ventilation opening of an electronic enclosure, the frameless vent panel comprising:
 a frameless dielectric panel having a thickness defined by a first side and a second side, a perimeter, and a plurality of apertures extending from the first side to the second side for allowing airflow therethrough;   at least one electrically-conductive material provided to the frameless dielectric panel for attenuating a transfer of electromagnetic energy from the first side to the second side; and   a resiliently compressible EMI gasket having a width substantially equal to the thickness of the frameless dielectric panel, the resiliently compressible EMI gasket being wrapped around the perimeter of the frameless dielectric panel and substantially covering the thickness defined between the first side and the second side.   
     
     
       36. The frameless vent panel of claim 35, wherein the resiliently compressible EMI gasket comprises electrically-conductive fabric wrapped over foam. 
     
     
       37. The frameless vent panel of claim 35, wherein the resilient compressible EMI gasket comprises electrically-conductive material coupled to a resiliently compressible member. 
     
     
       38. A frameless vent panel for providing electromagnetic interference (EMI) shielding for a ventilation opening of an electronic enclosure, the frameless vent panel comprising:
 a dielectric panel having a thickness defined by a first side and a second side, a perimeter, and a plurality of apertures extending from the first side to the second side for allowing airflow therethrough;   at least one electrically-conductive material provided to the dielectric panel for attenuating a transfer of electromagnetic energy from the first side to the second side; and   means for compressively fitting and retaining the frameless vent panel within the ventilation opening and for placing the frameless vent panel in electrical communication with the electronic enclosure,   said means disposed substantially about the perimeter of the frameless vent panel with said means substantially covering the thickness defined between the first side and the second side.   
     
     
       39. An electronic enclosure comprising:
 a ventilation opening;   a frameless vent panel within the ventilation opening for providing electromagnetic interference (EMI) shielding, the frameless vent panel including:
 a dielectric panel having a thickness defined by a first side and a second side, a perimeter, and a plurality of apertures extending from the first side to the second side for allowing airflow therethrough; 
 at least one electrically-conductive material provided to the dielectric panel for attenuating a transfer of electromagnetic energy from the first side to the second side; and 
 a resiliently compressible electrically-conductive edge substantially about the perimeter of the frameless vent panel and substantially covering the thickness defined between the first side and the second side, the resiliently compressible electrically-conductive edge compressively retaining the frameless vent panel within the ventilation opening in electrical communication with the electronic enclosure. 
   
     
     
       40. The electronic enclosure of claim 39, wherein the frameless vent panel is compressively retained within the ventilation opening by the resiliently compressible electrically-conductive edge without using any mechanical fasteners. 
     
     
       41. The electronic enclosure of claim 39, wherein the resiliently compressible electrically-conductive edge is compressed within the ventilation opening in a direction normal to the longitudinal axes of the apertures. 
     
     
       42. The electronic enclosure of claim 39, wherein the resiliently compressible electrically-conductive edge comprises a band of one or more materials, the band having a width substantially equal to the thickness of the dielectric panel and being wrapped around the perimeter of the dielectric panel such that the band substantially covers the thickness defined between the first side and the second side. 
     
     
       43. The electronic enclosure of claim 42, wherein the band of one or more materials comprises at least one or more of electrically-conductive foam, electrically-conductive fabric, and electrically-conductive fabric wrapped over foam. 
     
     
       44. The electronic enclosure of claim 39, wherein the resiliently compressible electrically-conductive edge comprises electrically-conductive fabric wrapped over foam. 
     
     
       45. The electronic enclosure of claim 39, wherein the resiliently compressible electrically-conductive edge comprises a resiliently compressible EMI gasket having a width substantially equal to the thickness of the dielectric panel and being wrapped around the perimeter of the dielectric panel such that the resiliently compressible EMI gasket substantially covers the thickness defined between the first side and the second side. 
     
     
       46. A method for electromagnetic interference (EMI) shielding a ventilation opening of an electronic enclosure, the method comprising positioning a frameless metallized dielectric vent panel within the ventilation opening such that the frameless metallized dielectric vent panel is compressively retained within the ventilation opening by a resiliently compressible electrically-conductive edge disposed substantially about the perimeter of the frameless metallized dielectric vent panel and substantially covering the thickness defined between a first side and a second side of the frameless metallized dielectric vent panel, and such that the resiliently compressible electrically-conductive edge places the frameless metallized dielectric vent panel in electrical communication with the electronic enclosure. 
     
     
       47. The method of claim 46, wherein the frameless metallized dielectric vent panel is compressively retained within the ventilation opening by the resiliently compressible electrically-conductive edge without using any mechanical fasteners. 
     
     
       48. The method of claim 46, wherein the frameless metallized dielectric vent panel includes a plurality of apertures extending from the first side to the second side for allowing airflow therethrough, and wherein positioning the frameless metallized dielectric vent panel within the ventilation opening includes compressing the resiliently compressible electrically-conductive edge within the ventilation opening in a direction generally perpendicular to the longitudinal axes of the apertures. 
     
     
       49. A method of making a frameless vent panel capable of providing electromagnetic interference (EMI) shielding for a ventilation opening of an electronic enclosure, the method comprising providing a frameless metallized dielectric vent panel with a resiliently compressible electrically-conductive edge substantially about a perimeter of the frameless metallized dielectric vent panel such that the resiliently compressible electrically-conductive edge substantially covers a thickness defined between a first side and a second side of the frameless metallized dielectric vent panel, the resiliently compressible electrically-conductive edge being configured for allowing the frameless vent panel to be compressively fit and retained within the ventilation opening in electrical contact with the electronic enclosure. 
     
     
       50. The method of claim 49, further comprising metalizing a dielectric panel to thereby create the frameless metallized dielectric vent panel before providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge. 
     
     
       51. The method of claim 49, wherein providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge comprises positioning a band of one or more materials about the perimeter of the frameless metallized dielectric vent panel such that the band of one or more materials substantially covers the thickness defined between the first side and said second side. 
     
     
       52. The method of claim 51, wherein the band of one or more materials comprises at least one or more of electrically-conductive foam, electrically-conductive fabric, and electrically-conductive fabric wrapped over foam. 
     
     
       53. The method of claim 49, wherein providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge comprises positioning electrically-conductive fabric wrapped over foam about the perimeter of the frameless metallized dielectric vent panel such that the electrically-conductive fabric wrapped over foam substantially covers the thickness defined between the first side and said second side. 
     
     
       54. The method of claim 50, wherein providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge comprises positioning electrically-conductive fabric about the perimeter of the frameless metallized dielectric vent panel such that the electrically-conductive fabric substantially covers the thickness defined between the first side and said second side. 
     
     
       55. The method of claim 49, wherein providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge comprises positioning electrically-conductive foam about the perimeter of the frameless metallized dielectric vent panel such that the electrically-conductive foam substantially covers the thickness defined between the first side and said second side. 
     
     
       56. The method of claim 49, wherein providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge comprises positioning a resiliently compressible EMI gasket about the perimeter of the frameless metallized dielectric vent panel such that the resiliently compressible EMI gasket substantially covers the thickness defined between the first side and said second side. 
     
     
       57. The method of claim 49, wherein providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge comprises positioning electrically-conductive elastomer about the perimeter of the frameless metallized dielectric vent panel such that the electrically-conductive elastomer substantially covers the thickness defined between the first side and said second side. 
     
     
       58. The method of claim 49, wherein providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge comprises providing edge treatment to the frameless metallized dielectric vent panel to create electrically-conductive protrusions extending outwardly substantially about the perimeter of the metallized dielectric vent panel. 
     
     
       59. The method of claim 58, wherein the electrically-conductive protrusions comprise at least one or more of a resilient spring finger, a dimple, or a combination thereof. 
     
     
       60. The method of claim 49, wherein providing the frameless metallized dielectric vent panel with the resiliently compressible electrically-conductive edge comprises positioning an electrically-conductive wire mesh about the perimeter of the frameless metallized dielectric vent panel such that the electrically-conductive wire mesh substantially covers the thickness defined between the first side and said second side. 
     
     
       61. The method of claim 49, further comprising providing the frameless metallized dielectric vent panel with flame retardant sufficient for achieving a flame rating of V0 under Underwriter's Laboratories (UL) Standard No. 94. 
     
     
       62. The method of claim 49, further comprising providing the frameless metallized dielectric vent panel with a corrosion inhibitor. 
     
     
       63. The method of claim 49, further comprising applying at least one coating to the frameless vent panel for enhancing at least one performance attribute of the frameless vent panel. 
     
     
       64. The method of claim 63, wherein the coating comprises at least one or more of a mildew inhibitor, a corrosion inhibitor, and a flame retardant.