Fully laminated mesh window

For an optimum combination of high transmission and best shielding properties, MTC offers shielded windows, which are usually used for visual display instruments or electronic housings.

Depending on the application, you can choose between different designs and materials to achieve the best values for e.g. transmission, electrical conductivity, breakage resistance or scratch resistance.

  • Very high shielding effectiveness
  • High scratching resistance
  • Very good possibilities for antireflection
  • Production according to customer specifications

More details about shielded windows.

The tolerances for our shielded windows can be found here.

Two substrates and an electrically conductive metal mesh are laminated together The mesh stands over the edge and can be connected directly to the chassis or it also can be done in combination with an electrically conductive gasket.

Selection of the base material:

  • glass (Float-, heat treated- and chemical toughened glass)
  • acrylic glass
  • polycarbonate glass

The following combinations are possible:

  • glass / mesh / glass
  • plastic / mesh / plastic

The very best shielding attenuation can be reached with fully laminated windows. Glass is scratch resistant and plastic is break proof.

Prior the lamination of the mesh the orientation of the mesh should be determined. In some applications a lamination at 90° can cause interferences with the display (so called Moire effect).

To avoid reflections and to improve the contrast, the fabrics are generally blackened. This process does not modify the electrical conductivity of the fabric.

The aperture size of the mesh (opi = openings per inch) affects the transparency of the window. If there is a high-resolution graphic used in the application, the use of a fabric is not recommended. In this case an electrically conductive metallized substrate should be used.

Variety of meshes

Blackened mesh opi Wire-Ø in mm
100 0,05
50 0,025
* 100 0,025

* silver plated and blackened

Attenuation (dB)

0,01 MHz 0,1 MHz 1,0 MHz 100 KHz 1,0 MHz 10 MHz 100 MHz 400 MHz 1,0 GHz 10 GHz
H-field H-field H-field E-field E-field E-field E-field E-field P-field P-field
Option 1 (single layer) 3 7 21 98 93 78 65 60 50 -
Option 2 (two layers) * * * 123 152 124 111 115 94 67

* We have not tested double mesh windows at this frequency.

Option 1 refers to a single layer of mesh 100 opi blackened copper 0.05 mm wire diameter.
Option 2 refers to two layers of mesh 100 opi blackened copper 0.05 mm wire diameter.

Test methods and procedures in accordance to MIL-Std 285.

Test results base on a RFI shielded window size 1000 x 1000 mm.

To prevent unwanted reflection of light it is suggested to add an antireflection coating to the substrate.

Possibilities at mineral glass:                 

  • Multi-layer coating according to MIL SPEC 675 B (less than 0,6% rest of reflection)
  • Single-layer coating according toDIN 58197 (less than 1,5% rest of reflection)
  • Chemical etching:

     5% anti reflection (called GW 80)
     9% anti reflection (called GW 100)
     13% anti reflection (called GW 120)

Possibilities at plastic:

  • Multi-layer coating according to MIL SPEC 675 B (less than 0,6% rest of reflection)
  • Single-layer coating according to DIN 58197 (less than 1,5% rest of reflection)Chemical etching (very diffuse)
  • Chemical etching (very diffuse)
  • Anti-scratch, anti-reflection coating by spraying
 
Give us a call:
+49 [0] 90 71 - 79 45 - 0
 
Contact us:
info@mtc.de
 
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