This little chip, dated from 1973, is part of the history of what we are surrounded by, LEDs. And they have an unlikely and somewhat surprising beginning. The MCT2 is an opto-coupler, basically an LED and a phototransistor in a single package, used for isolating digital signals. The important portion here is the LED. LEDs are in nearly every electronic product these days, and this Christmas season we see many Christmas lights that are now LED based. THey are more efficient, and much longer lasting. Certainly the eco-friendly choice for lighting. And they have their roots in a company that does not always elicit an eco-friendly discussion.
That would be Monsanto.
That big ‘M’ on the package is for Monsanto, who from 1968-1979 was the leading supplier of LEDs and opto-electronics. In 1968 there were exactly 2 companies who made visible light LEDs (red), HP and Monsanto, and HP used materials supplied by Monsanto to make theirs.
Monsanto did not set out to make LEDs, they were a chemical company, they made various chemical compounds, plastics etc. One of those compounds (crystals in this case) was Gallium Arsenic Phosphate (GaAsPh). GaAsPh turns out to be
very useful as a semiconductor for light emitting diodes. This is what Monsanto set out to make, hoping to having other companies build the LEDs from the GaAsPh they produced (which is how HP started into the LED display business).
Monsanto made LEDs. and opto-electronics, becoming one of the pioneers of the industries, in the first few years of production, sales were doubling every few months, making it a very profitable industry. By the late 1970’s every one was making opto-electronics and LED’s wither with patents licensed from Monsanto, or with processors of their own design. As profit margins dwindled, Monsanto sold off the division to General Instrument, exiting the LED business in 1979.
So as you look at your LED light bulbs, or your festive Christmas tree lit with LED Christmas lights, take a moment to thank Monsanto. (or at least start a lively discussion with your holiday guests)