|Soviet AL304V Surface Mount LED
|Written by AnubisTTP on 2012-11-03
Most Western manufacturers abandoned the multiple die style construction of the Monsanto MAN-3 before a viable green LED chemistry was developed; nearly every LED calculator in the world uses red LED displays. The Soviets were one of the few groups still manufacturing transparent single-die 7-segment LED's at the time green LEDs were commercialized, and as such this Soviet-era MAN-3 clone is a strange beast: a green LED constructed in classic vintage single die style. The display is very nearly the same size and shape as a Monsanto MAN-3 and contains seven elongated dies for the segments and an eighth square die for the decimal point. The dies are not divided into multiple active 'dots' as in other displays of this construction style. Instead, the entire surface of the die emits light. The LED package is almost perfectly clear and the ground plate is cut to match the shape of the segments, which gives these displays a striking transparent appearance not shared by other vintage LEDs.
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AL304V green surface mount LED display, normal operation.
AL304V LED shown with identically sized 3LS314 display for scale. Note the transparency of the green LED display packages.
At 30x magnification, the structure of the dies can be seen.
LED dies, 150x magnification. Light is emitted from the entire surface of the die not covered by the cross shaped contacts.