EMI/RFI shield for visual display terminals

• US 4,910,090 A
• Filed: 10/21/1987
• Issued: 03/20/1990
• Est. Priority Date: 10/21/1987
• Status: Expired due to Term

• Current Assignee: Southwall Technologies, Inc. (Eastman Chemical Company)
• Original Assignee: Southwall Technologies, Inc. (Eastman Chemical Company)
• Inventors: Behling, Gerald R., Kuhlman, Bruce E., Kloss, James E.
• Primary Examiner(s): Thibodeau, Paul J.
• Application Number:
  US07/111,201
• Time in Patent Office: 881 Days
• Field of Search: 428/411.1, 428/469, 428/457, 358/252, 358/253, 358/255, 358/247, 174/35 MS, 174/35 GC, 350/276 SL
• US Class Current: 428/469
• CPC Class Codes: H01J 29/868 Screens covering the input or output face of the vessel, e.g. transparent anti-static coatings, X-ray absorbing layers
• CPC Class Codes: H04N 5/65 Holding-devices for protective discs or for picture masks
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

A multilayer composite EMI/RFI filter for use in front of visual displays is disclosed to be constructed of a shaped or shapable plastic substrate having an outer diffuse hardcoat and one or more conductor transmissive layers of metal. Preferably the metal is presented as a sputter-deposited dielectric-metal-dielectric stack.

Claims

1. A transparent EMI/RFI shield for use in front of a visual display comprising:

an outer layer of diffuse nonglare hard-coat;

an intermediate plastic substrate, said substrate being sized and shaped to conform to the visual display; and

an inner conductive layer, said conductive layer comprising a continuous nonmesh metal film layer intermediate dielectric layers, said conductive layer having a transmittance over the visual spectrum of at least about 30% and having an electrical resistance of less than about 10 ohms per square, and said conductive layer being connected on substantially its entire periphery to a groundable conductor.

2. The transparent EMI-RFI shield of claim 1 wherein the plastic substrate is tinted or pigmented to give a transmittance between 30 and 100%.

3. The transparent EMI/RFI shield of claim 1 having a resistance of less than about 5 ohms per square.

4. The transparent EMI/RFI shield of claim 1 having a curved cross-section.

5. The transparent EMI/RFI shield of claim 1 having a flat cross-section.

6. The transparent EMI/RFI shield of claim 1 wherein the metal layer comprises a continuous nonmesh 100 to 500 angstrom layer of conductive metal.

7. The transparent EMI/RFI shield of claim 6 wherein the metal comprises silver.

8. A transparent EMI/RFI shield for use in front of a visual display comprising:

an outer layer of diffuse nonglare hard-coat;

an intermediate plastic substrate, said substrate being sized and shaped to conform to the visual display; and

an inner conductive layer, said conductive layer comprising a plurality of continuous metal layers bounded by and separated by dielectric layers said conductive layer having a transmittance over the visual spectrum of at least about 30% and having an electrical resistance of less than about 10 ohms per square, and said conductive layer being connected on substantially its entire periphery to a groundable conductor.

9. The transparent EMI/RFI shield of claim 8 wherein the plurality is two.

10. The transparent EMI/RFI shield of claim 8 wherein the plurality is three.

11. The transparent EMI/RFI shield of claim 9 wherein the metal comprises silver.

12. The transparent EMI/RFI shield of claim 11 wherein the dielectric comprises metal oxide.

13. A transparent EMI/RFI shield for use in front of a visual display comprising:

an outer layer of diffuse nonglare hard-coat;

an intermediate plastic substrate, said substrate being sized and shaped to conform to the visual display; and

two dielectric/continuous metal/dielectric conductive layers--one on either side of the plastic substrate said conductive layers each comprising a continuous metal film layer intermediate dielectric layers, said conductive layers having a transmittance over the visual spectrum of at least about 30% and having an electrical resistance of less than about 10 ohms per square, and said conductive layers being connected on substantially their entire periphery to a groundable conductor.