General
low-power LED modules (such as direct lighting applications, buttons or
dashboard lights) are mostly carried out with silver plastic solid
crystal, which is currently in the industrial sector where LED has been
the most widely used solid-crystal technology. The so-called silver
plastic is actually a large number of silver powder mixed with epoxy
resin inside, to make it conductive and thermal conductivity. Although
a large number of silver powder can be mixed with the silver plastic to
obtain a high thermal conductivity (> 30W/mK), but also because of
the relative decline in the proportion of epoxy-tree, resulting in poor
strength of solid crystal, making the original use of lower thermal
resistance to increase the reliability degree of approach, results in a
solid crystalline solid strength caused by poor quality of instability.
Moreover, silver epoxy adhesive composition itself and can not
withstand high temperatures, especially when the chips operate in more
than 2W high current (eg 700mA), at the same time enhance the
brightness, on-chip hot spots (hot spot) heating phenomenon is very may
be caused by silver adhesive main reason for quality deterioration.
Even so, the silver colloidal crystalline solid way to process due to
lower cost, making the process relatively easy for many, is therefore
still in the industrial sector has been widely adopted. |
