This is PAGE 2 of the 1960s exhibit. Go here for PAGE 3.




1960-1969: THE LED IS BORN


These pictures are of a 940nm IR LED illuminating the type of phosphor used in General Electric's SSL-3 green LED from the late 1960s.
The SSL-3 uses a 940nm gallium arsenide LED chip covered with a downconverting phosphor that converts some of the infrared energy into a very narrow band of green light centered at 540nm.

NOTE: The original SSL-3 LED came in a metal can; these pictures are of a more modern lamp illuminating an anti-Stokes phosphor IR detector card to give some approximation of the original SSL-3's color.

The whitish blue glow coming from the chip is actually infrared as the digital camera "sees" it.
Photos courtesy of Paul Schick.



Here is part of the spec sheet for this LED, as published by General Electric in 1969.
This was *after* the laboratory samples of this LED had been burned in for two years.
Scan courtesy of Paul Schick, data on this image is (C)copyright 1969 General Electric.




This is PAGE 2 of the 1960s exhibit. Go here for PAGE 3.





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