IPC Subgroup
G09F 21/16 Sky-writing
Introduced: September 1968
Last revised: January 2006
Full Title
Mobile visual advertising > by aeroplanes, airships, balloons, or kites > Sky-writing
Classification Context
- Section:
- PHYSICS
- Class:
- EDUCATING; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- Subclass:
- DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
Related Keywords
SKY [writing]advertising by sky WRITING