While PureView is associated with high-end camera smartphones, first introduced with the Nokia PureView 808, ClearBlack technology by Nokia was used for lower reflectivity displays meant for better legibility in sunlight. The display is meant to deliver better colours and deeper blacks even in direct sunlight, which makes it quite useful for mapping applications.
Lumia as we know is a brand name started off by Nokia for its Windows Phone devices partnered with Microsoft. Asha on the other hand is the branding formerly used by Nokia for its 'smart' feature phones. Notably, Microsoft has also kept Surge and Mural, the Symbian trademarks from 2009. Nokia Surge and Nokia Mural were the names of Symbian-powered handsets released on AT&T in US in 2009.It still remains unclear what plans Microsoft has in keeping these two trademarks (Surge and Mural), when Nokia had ditched Symbian and these trademarks before its acquisition by Microsoft.