Thanks Arch...very interesting read.
I'm pretty sure it's working...the picture that i posted was when you hold the watch under the light

Some additional information :
1977: The LCD 'Micro Computer' or 'Chronomat' of National Semiconductor USA receives a tremendous amount of attention at the Basle Fair 1977. It was a truly scientific watch calculator. The watch contained the smallest wrist calculator ever produced at that time. It was sold by a number of different firms: Belltime of the Netherlands, Bell Telephone of Belgium, Chronar Corp. Princeton USA, Marcel Watch Co. of New York, The International Display Centre of Antwerp, Belgium, Bapic S.A. Geneva and Louis Erard of La Chaux-de-Fonds, Switzerland. It was possible to deliver the watch with or without solar-cells.
source : Pieter Doensen :
http://doensen.home.xs4all.nl/q1.htmlcheck this also from Pieter Doensen : " 1975 A prototype of a mini watch-calculator made by Optel Corporation Princetown, New Jersey is presented at the Basle Fair by Eurotime."
and see the picture in the post from Arch...
It says playboy juni 1975!"1975 The first watch with a built-in calculator is the 'Pulsar Time Computer-Calculator', caliber 901, with a light emitting diode (LED) display. Just before Christmas 1975, the first one hundred produced in gold (750/1000) were sold in one day for US $ 3.950,- each. It was shock resistant up to 2,500 times its own weight. Four batteries were required for one year's use. A special command pen was issued with the Pulsar Time Computer-Calculator, to operate the small calculation keys. In 1977, the first steel models with two batteries were sold. In the same year, Pulsar issued three models of a bar shaped calculator pocket-watch with a chain, gold, silver and goldplated silver."
Just before christmas 1975