[Wavytone]

Bob they are japanese "makers marks", much like the "hallmarks" on fine english silverware. From a thread on CN recently:

Badge SOC=Showa Optical Company (Not the same as S.O.C)
Circle T-Towa
Circle Dash (-)= Carton Optical Co
Diamond N = Eikow
Circle Y (upside down) = Eikow or Towa (circle split in 3 symmetrical parts)
Circle K-Kenko or Koyu (Vixen was originally a trade name used by Koyu)
Diamond Z-Tanzutsu
Diamond SYW-Yamamoto
Circle + (plus)-Shimadzu Seisakusho
Circle W- ???
Diamond BOL - Bushnell Optical Labs
HOC-Hino Optical Company
Circle V-Vixen
Crown Goto-Goto Optical (why can’t they all be this easy!)
Circle A-Astro Optical
Circle G, backwards G, in a cross-Astro Optical-Older
COC-Carton Optical Company
APL-Apollo Business & Industry-Bought by Koyu, then Vixen.
AvA=Takahashi on Swift
Star on Crescent-Nishimura
KOL-King Optical
Diamond K = Tasco but original manufacturer unknown
NS = Nihon Seiko, rebranded as University Optics