1986 - Citizen Analog with Solar Cell
This line followed up on the Crystron by Citizen, the first solar analog watch. In 1986 three models were introduced in Japan ( SR90-1021U, SR90-1031U and SR90-1011U). This watch incorporated two important improvements over the Crystoron. It has a more efficient solar cell, amorphous silicon developed by RCA. This new type of solar cell was much more efficient in transforming light into electricity. The other improvement was in the secondary cell. The new watch has a “large capacity condenser” allowing it to hold a charge longer than the Cryston. However, this improvement only allowed the watch to hold a charge for a week to 10 days.
I have not been able to find examples or images of these first watches in the “Analog with Solar Cell” line. I would appreciate hearing from anyone who could help me locate an example.
Citizen made the line of "With Solar Cell" watches for a number of years. Here is an undated example.