CADMIUM SULFOSELENIDE SURFACE-MOUNTABLE OPTOCOUPLER

摘要

The invention concerns an optocoupler. The optocoupler includes a substra te made of optically opaque electrically insulating material metallized to provide conductive traces on a top surface thereof which are electrically linked to metal pads on a bottom surface. A cadmium sulfoselenide photoresistor having an active surface is placed over the substrate with the active surface facing the substrate where the photoresistor has two electrodes. Metal leads connect each of the two electrodes of the photoresistor to two metallized traces on the substrate. A light emitting diode (LED) chip is mounted on the substrate facing the active surface of the photoresistor. The LED chip has a top and bottom electrode, where the bottom electrode is electrically attached to a third metallized trace and the top electrode is wire bonded to a fourth metallized trace. A cover made of optically opaque material is fixed to the substrate so as to enclose the photoresistor and th e LED chip in a light tight enclosure. In an alternative embodiment of the invention, the photoresistor and the LED chip can lie side by side and be in optical communication with each other through a reflective coating on the inside of the cover.