BlackBerry has filed a lawsuit against Typo Products over alleged infringement of its designs of a keyboard case.

The Canadian smartphone maker alleged that Typo’s external case for Apple’s iPhone 5 and iPhone 5s devices incorporating a physical keyboard, infringes its patents and designs used for the Q10.

BlackBerry general counsel and chief legal officer Steve Zipperstein said this is a blatant infringement against BlackBerry’s iconic keyboard.

"From the beginning, BlackBerry has always focused on offering an exceptional typing experience that combines a great design with ergonomic excellence," Zipperstein said.

"We are flattered by the desire to graft our keyboard onto other smartphones, but we will not tolerate such activity without fair compensation for using our intellectual property and our technological innovations."

Typo has already started taking orders for the keyboard cases, with the products scheduled for shipments this month.

The Canadian smartphone maker has been seeking to spin its fortunes upon losing ground to Apple and Samsung in the global mobile phone and smartphone market.

BlackBerry’s share of the global smartphone market reached just 1.7% in Q3 over 4.1% during the corresponding period a year earlier.

In September 2013, Blackberry agreed to be acquired by a consortium led by Fairfax Financial for $4.7bn, while it again ditched plans in early November instead hoping to raise $1bn (£627m) of finance as its chief executive Thorsten Heins quits.