Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/~phil/hardware/lr/window_shield.pdf Дата изменения: Fri Feb 10 16:35:05 2006 Дата индексирования: Sat Sep 6 07:08:59 2008 Кодировка: Поисковые слова: созвездие лебедя

SHIELDED WINDOWS

WIN-SHIELD Elite EMI Shielded Windows
TM

WIN-SHIELDTM Elite EMI Shielded Windows
WIN-SHIELDTM Elite EMI shielded windows provide exceptional optical performance without sacrificing EMI shielding. This new generation of shielded windows is designed specifically to address shielding concerns in electronic equipment, especially medical devices, industrial process, measurement and control equipment, and test equipment. WIN-SHIELDTM Elite windows use a proprietary mesh shielding design that provides superior light transmission and EMI shielding properties when compared to traditional shielded window designs. Total shielded window light transmittance properties (Figure 4), result from the mesh, substrates and surface finishes used. This new design also minimizes the typical problem with text distortion on display screens caused by the shielding mesh orientation, i.e., the moirИ effect. Through improved, efficient manufacturing operations, these features are available at prices typically below conventional shielded windows. WIN-SHIELDTM Elite EMI shielded windows are manufactured as a fully laminated construction with optically matched adhesives and front and rear

Conventional Mesh
UL 94V-0 rated, optical grade, polycarbonate substrates. Standard finish for the front surface is a non-glare hardcoat. A clear hardcoat finish is standard on the rear surface. An optional clear hardcoat is available on the front surface. The shielding media is provided by the proprietary mesh design. WIN-SHIELDTM Elite windows are available in standard 1.5 mm (0.06 in.),

WIN-SHIELDTM Elite
2.0 mm (0.078), 2.5 mm (0.10 in.), 3.0 mm (0.12 in.) and 4.0 mm (0.157 in.) thicknesses. Window termination can be either square or stepped, with Chomerics silver epoxy busbar. WIN-SHIELDTM Elite windows are also available with Chomerics' SOFT-SHIELD® 5000 EMI gasket termination. SOFT-SHIELD 5000 gaskets feature a conductive cloth over urethane foam core. (See SOFT-SHIELD 5000 page.)

Figure 1 ­ Termination for WIN-SHIELDTM Elite Windows
WIN-SHIELDTM Elite EMI Shielded Window Gasket Options
SOFT-SHIELD 5000 EMI Gasket SOFT-SHIELD 5000 EMI Gasket

WIN-SHIELDTM Elite Standard Thickness
1.5 mm

Allowable Step Depth from Front Surface Rear Surface
Max.0.5 mm (0.020") 0.0 mm

0.6 mm 3.0 mm
1.4 mm Step

1.0 mm Silver epoxy busbar 3.0 mm Silver epoxy busbar

2.0 mm

Max.0.5 mm (0.020")

Max.0.5 mm (0.020")

Termination/Edge Options: (Colored lines represent silver paint or foil busbar.)
Option #1 Option #2 Option #3 Option #4 Option #5 Option #6

2.5 mm

Max.1.3 mm (0.050")

Max. 1.3 mm (0.050")

Max.1.8 mm (0.050")

Max. 1.8 mm (0.070")

3.0 mm

Step depths between ) 0.6 and 1.2mm are not allowed

Max.2.8 mm (0.110")

Max. 2.8 mm (0.110")

4.0 mm

Step depths between ) 0.8 and 1.2mm are not allowed

1

US Headquarters TEL +(1) 781-935-4850 FAX +(1) 781-933-4318 · www.chomerics.com Europe TEL +(44) 1628 404000 FAX +(44) 1628 404090 Asia Pacific TEL +(852) 2 428 8008 FAX +(852) 2 423 8253 South America TEL +(55) 11 3917 1099 FAX +(55) 11 3917 0817


Table 1 WIN-SHIELDTM Elite WINDOW SPECIFICATIONS
Front Surface Rear Surface Substrate EMI Shielding Effectiveness Scratch Resistance Light Transmission Quality Standard Thickness Maximum Window Size Termination Part Numbering Temperature Range Non-glare hard coating. Clear hard coat. Clear hard coat is standard High optical grade polycarbonate. See Figure 2 High scratch resistance to Pencil Test Type 2H. 65-70% for the final assembly (Figure 4) WIN-SHIELD Elite windows are manufactured and inspected to Chomerics Optical Inspection Standard. 1.5 mm (0.06 in.), 2.0 mm (0.08 in.), 2.5 mm (0.10 in.), 3.0 mm (0.12 in.), 4.0 mm (0.15 in.) with +/- 0.3 mm (0.01 in.) tolerance is standard. Other thicknesses are available on request Maximum window size is 500 mm x 660 mm (19.6 in. x 25.9 in.) (Depending on mesh angle) Square or step finishes with Chomerics silver epoxy busbar and Chomerics SOFT-SHIELD® 5000 low closure force EMI gasket (Figure 1) Chomerics Part Numbers follow the format E-01-XXXXX and will be assigned by Chomerics -40°C to +75°C

LIGHT TRANSMITTANCE
The light transmittance for a shielded window is a composite result of the effect of the shielding media, which includes the mesh, the front and rear substrates, and the surface finish on the substrates. The following figures and tables demonstrate how visual transmission is determined from the finished window assembly.

Mesh Light Transmittance
Figure 3 shows the percentage of light transmission for several different types of mesh used in typical EMI shielded windows. A = WIN-SHIELDTM Elite mesh B = blackened copper 100 opi/0.0022 in. (0.06 mm) wire diameter C = plain copper 100 opi/0.0022 in. (0.06 mm) wire diameter D = blackened/plated stainless steel 80 opi/0.0012 in. (0.03 mm) wire diameter

Figure 2 Shielding Effectiveness for WIN-SHIELDTM
Elite Windows
(Measured via a modified MIL-STD-285 test procedure, CHO-TM-TPO8, using a 14 in. x 14 in. open aperture)
WIN-SHIELDTM Elite EMI Shielded Window Performance (Typical)

Figure 3 Mesh Light Transmittance
80 % Transmission 70 60 50 40 A B C Mesh Type Mesh Type D

100 90
Shielding Effectiveness (dB)

80 70 60 50 40 30 20 10 0 10 100 1,000 10,000

Frequency (MHz)

US Headquarters TEL +(1) 781-935-4850 FAX +(1) 781-933-4318 · www.chomerics.com Europe TEL +(44) 1628 404000 FAX +(44) 1628 404090 Asia Pacific TEL +(852) 2 428 8008 FAX +(852) 2 423 8253 South America TEL +(55) 11 3917 1099 FAX +(55) 11 3917 0817

2


Substrate and Surface Treatment Light Transmittance
Table 2 shows the light transmittance of common shielded window substrates. Table 3 shows the light transmittance reduction for various sur face finishes used on substrates for EMI shielding windows.

Figure 4 Shielded Window Light Transmittance
80

% Transmission

70 60 50 40 W X
Unblackened Copper Blackened Copper

Table 2
SUBSTRATE LIGHT TRANSMITTANCE
Substrate Plain Clear Clear Clear "float" glass polycarbonate* acrylic* polyester* Light Transmittance 90-92% 85-90% 85-90% 83-88%

Y
Blackened Stainless Steel WIN-SHIELDTM Elite

Z

*varies with thickness due to internal dispersion

Table 3 SURFACE FINISH LIGHT TRANSMITTANCE REDUCTION
Surface Finish Non-glare coatings (60-70 gloss) Non-glare coatings (80-90 gloss) Clear hard coat MLAR* coating on glass
*multi-layer, anti-reflecting

W = EMI shielded window 0.64 mm (0.025 in.) thick with polycarbonate substrates, with non-glare coating on the front surface and clear hard coat on the rear surface X = EMI shielded window 1.2 mm (0.047 in.) thick with glass substrates, plain finish to both front and rear surfaces. Y = EMI shielded window 1.5 mm (0.059 in.) thick with polycarbonate substrates, with non-glare coating on the front surface and plain polycarbonate on the rear surface. Z = EMI shielded window 1.2 mm (0.047 in.) thick with glass substrates, MLAR (multi-layer anti-reflecting) coating on the front surface and plain glass on the rear surface.

Light Transmittance Reduction 2-3% 1% <1% <1%

Total Shielded Window Light Transmittance
Figure 4 details the actual light transmission of several types of EMI shielded windows, avoiding the common error of quoting the open mesh light transmission performance as that of the finished window.

3

US Headquarters TEL +(1) 781-935-4850 FAX +(1) 781-933-4318 · www.chomerics.com Europe TEL +(44) 1628 404000 FAX +(44) 1628 404090 Asia Pacific TEL +(852) 2 428 8008 FAX +(852) 2 423 8253 South America TEL +(55) 11 3917 1099 FAX +(55) 11 3917 0817