PDP

1
Attachment A
The Description for the Application
for Exempting Lead in Plasma Display Panels from
the RoHS Directive
2
Todays commercially available plasma
display panels ( PDPs ) comprise lead glasses,
which are formed by firing glass powders with
proper softening temperatures and glass
transition temperatures, shown as figure 1.
Upper limit ( avoiding substrate deformation)
As shown in table 1, lead glasses satisfy
all the properties required for fabricating PDPs,
which causes common use of lead glasses. Some
candidates for lead-free glass alternatives,
including bismuth glasses, zinc borate glasses,
and tin phosphate glasses, do not satisfy the
required properties. Therefore, new materials
will have to be developed to realize lead-free
PDPs.
600?
Softening Temperature
Glass Transition Temperature
500?
Temperature
Table 1 Glass Properties Required for PDP
Fabrication
Lead-Free Glasses
Required Properties
Lead Glasses
Zinc Borate Glasses
Tin Phosphate Glasses
Bismuth Glasses
400?
Softening Temperature Adjustable between
350 600?
Lower limit ( capable of sealing)


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Front Dielectric Layer
Rear Dielectric Layer
Barrier Rib
Seal
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High Transparency

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Expansion Coefficient Same as glass substrates
Front Panel

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Glass Substrates
Chemical Stability Inactive to
electrode materials
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Rear Panel
Figure 1 Glasses Composing PDPs and Their
Softening Temperatures and Glass Transition
Temperatures
? very good ? good ? fair bad
?no information