Patek Philippe, “Ellipse d’or”, References 3546, 3548 and References 3648, 3746, 3748
The references 3546 and 3548 were launched in 1967 and remained in production until the mid-1970s.
The majority in yellow gold, more rarely in white gold.
A few thousand examples have been produced, available with different type of dials (especially the blue colour “sunburst” dial; an 18K gold physically transformed by exclusive Patek Philippe process) and bracelets (Ref. 3546-1, 3546-2, etc.).
The “Ellipse d’or” model was inspired by the “Golden section” (“Divina proportione” or “Proportio continua”), which is the perfect equilibrium of shapes and corresponds to the ratio 1/1.6181.
The Ref. 3546 is with lugs, while the Ref. 3548 is without visible lugs (but with a central lug on the reverse of the watch). The cases were produced by Fr. Baumgartner in Geneva but the last cases were made by Favre & Perret in La Chaux-de-Fonds.
Both references were replaced in 1976 by Ref. 3648, 3746 and 3748 (Cal. 215).
The family of the Golden Ellipse watches is still in production today, making it one of the most long-lasting models ever manufactured by the firm.
· Patrizzi, 2010, vol. 2, p. 235.
In the 1970s, the presence of the two Greek letters “Sigma” on either side of “SWISS” was intended to give a distinctive sign to Swiss-made dials with solid gold hour-indexes. Only members of APRIOR (Association pour la Promotion Industrielle de l’Or) were entitled to use this mark; among them, Patek Philippe, Rolex, Vacheron Constantin, IWC and Omega.