As led lighting chips cannot be used directly, so it must be fixed to the bracket for the use of the device, chip and support to pass “line” led to filling the current conductor, leads. By line is very fine, only 0.1 mm in diameter.In addition, Due to the chip surface must be free of water, natural gas and other material erosion, so the same should be solid protection, which you would need to use transparent materials with extremely high rates of potting. General common transparent epoxy or silicone transparent chip protection of such materials.
We know that if the chip interface for direct contact with the air, because the chip material close to the light refraction coefficient of air is large, will lead most of the light is reflected back to the chip in the chip, cannot escape into the air. A case study of GaAs material, interface, chip the critical angle of total reflection of about 140, 4%^’12% photons can only escape into the air. If refraction coefficient of 1.5 epoxy chip interface, its critical angle of total reflection about 22.6 per cent, increase the rate of escape of the light. And if do with ball-type epoxy resin and air interface, its almost most of the photons can escape into the air, is reflected not only through 4%, so by choosing packaging material refraction coefficient of interface with the chip package can improve the efficiency of led light.
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