They used the Think(Pad|Centre) brand and expanded it to other things (like IdeaPad).
replyThey basically bought IBM's good reputation name and style and used it for both IBM-alikes and budget machines.
Some of it was good machines, some of it was crap.
They actually bought entire ThinkPad R&D as well, and have been subcontracted manufacturer for some time before that.
replySo Thinkpads are still designed in ex-IBM Lenovo Japan