Cool! Thorn is a name not generally heard this side of the pond.

I'm surprised that Canada made Thorn light bulbs not at USA, mostly Thorn made at Europe and Australia

The "pacman" is the factory code. This type of "symbol" factory code is normally used by Philips, so it is probably a Westinghouse lamp as Philips and Westinghouse are "alligned" in much the same manner as Sylvania and Osram are.
This particular code denotes the NORELCO plant in London, Ontario. There is probably a Roman Letter/Arabic Numeral combination, either near this symbol or symetrically opposite on the etch, this will be the date code. These two things define boath the place and time of creation of the lamp.