Dontech’s Optical Fine Wire (OFW) and Micro EMI-Mesh (MEM100) for EMI/RFI Shielding Filters and Windows

Dontech manufactures a wide variety of conductive optical grids, including woven fine-wire stainless steel and copper, as well as printed silver meshes for optical EMI/RFI shielding of electronic displays, instrumentation and enclosures.

The conductive optical grids are typically embedded in glass or plastic substrates such as acrylic, polycarbonate or polyester (PET) or triacetate (TAC). The conductive ground plane is then terminated via a perimeter busbar, extended mesh or conductive gasket.

Dontech’s grid counts typically range from 50 to 255 openings per inch (opi). Standard unplated wire width/diameter for most mesh counts is 0.0011” and 0.0022” for woven and 0.0005″ for etched mesh. Dontech’s OFW and MEM100 meshes combine excellent shielding effectiveness with optical performance, making them ideally suited for electronic displays and optics applications.

Typical applications for conductive optical grids include EMI/RFI shielding of electronic displays and enclosures used in:
Military applications – requiring the attenuation of radiated
EMI/RFI emissions and susceptibility per MIL-STD-461 and MIL-STD-464
Rugged computers, tactical radios, sensors and vehicle-mounted displays
Secure communication systems to meet tempest and FCC compliance and for homeland security
Medical displays – MRI rooms, display and observation windows
Aircraft Shielding – display and instrument panels, aircraft windows and doors
Industrial controls, heavy equipment, shipboard electronic systems
Test and measurement equipment – telecommunication, signal analyzers and generators

Dontech woven fine wire mesh is available unplated, blackened, or silver plated and conductively blackened. In addition, a variety of product configurations are available for all conductive optical grids, including:

  • Laminated in optical substrates: glass, polycarbonate, acrylic, ADC, PET
  • Optical finishes – antiglare, antireflective, chemical/abrasion resistant
  • Sheets, cut-to-size
  • Applied to metal frames and gasketed
  • Applied to touch screens and digitizers

 EMI Shielding Performances

Testing conducted at an independent lab, per IEEE 299 1997.
Mesh
Composition
Base Material/
(Plated Deposit)
Openings/
inch
Wire
Diameter
(inches)
Open
Area
H Field
E
Plane Wave
1
MHz
10
MHz
100
MHz
400
MHz
1
GHz
10
GHZ
Stainless Steel1
50
0.0012
88.4%
63
63
60
59
42
18
Stainless Steel1
80
0.0011
82.0%
68
69
70
55
44
26
Stainless Steel1
100
0.0011
79.2%
72
71
67
63
52
34
Copper2
100
0.0022
60.8%
89
90
84
77
62
42
MEM100-80
Etched Copper Mesh3
80
0.0005
86.0%
67
66
56
49
47
24
Stainless Steel2
230
0.0014
46.0%
97
77
73
62

All Dontech Ag-plated and MEM100 meshes offer resistivity of <0.05 ohms/sq.

Notes:
1 Silver-plated and conductivity blackened
2 Mesh (tested per NSA-65-6 and MIL-STD-285)
3 MEM100 Mesh is available in other mesh counts (openings/in.)

Mesh Configurations
Product Range: Mesh available in Sheets, Cut-to-Size, Laminated
Substrates: Glass, Polycarbonate, Acrylic, PET, ADC
Size: Up to 4 ft. x 8 ft.
Thickness: 0.015 in. to 0.5 in.
Optical Finishes: Clear/Gloss or Antiglare Coating for Plastics
Antireflective
Antireflective/Antiglare
Design Options: Contrast Enhancement
Colors (short pass, long pass, band pass)
Neutral Density, Circular Polarizers
NIR Blocking Filters
Transparent Heaters
Standard Plain Woven Wire Meshes
Wire Type
Count
Diameter (in.)
Open area (%)
304 SS
50
0.0012
88.4
304 SS
80
0.0011
83.2
304 SS
100
0.0011
79.2
Copper
100
0.0022
60.8
316 SS
100
0.0022
60.8
Copper
145
0.0022
46.4
304 SS
150
0.0011
70.7
304 SS
180
0.0011
65.5
304 SS
200
0.0011
62.0
304 SS
230
0.0011
55.8
304 SS
250
0.0011
54.0

 

EMI Filter Termination Methods

EMI-FilterTermMethods

Dontech Optical Fitting Process and Moiré Testing
Because a diffractive interference pattern (moiré) can occur due to the optical interference between the wire conductive optical grid with the light transmitting pixels of the electronic display, it is often necessary to rotate the mesh to reduce or eliminate this interference. Because most displays have a pixel orientation at 90 degrees, the moiré effect can be minimized by rotating the mesh at a 45 degree orientation. In addition to rotating the mesh, altering the pitch, mesh depth in the substrate or surface finish of the substrate can also minimize this moiré pattern.In rotating the mesh, Dontech designates mesh orientation as degrees from the positive horizontal axis. Common mesh orientations toreduce moiré include 45 deg., 30 degrees, and 22.5 degrees. As a service, Dontech utilizes both pre-production and in-process testing to verify that the designed orientation does not produce a moiré patterns.
Company Profile:
Dontech Incorporated is an ISO-9001:2008 designer and manufacturer of optical filters, coatings and enhanced display products for military, medical and industrial applications. Since 1971, Dontech has provided innovative optical solutions worldwide.

 

For additional information, please contact a Dontech applications engineer, download a copy of the Optical Fine Wire and MicroEMI-Mesh for EMI/RFI Shielding Filters and Windows data sheet, or request that a hard copy of the data sheet be sent to you.