The HTC Butterfly features a 5-inch screen with a pixel density of 440 ppi (pixels per inch) and full 1080P HD resolution, compared to the iPhone 5's 4-inch screen at 326 ppi at a lower resolution. (For full specs see: HTC Butterfly goes global with its 5.0-inch, full-HD display)
"We are confident that HTC Butterfly will set a new example for high-end smartphones," chief executive Peter Chou said at the launch in Taipei.
HTC sells its own smartphones and also makes handsets for a number of leading US companies, including Google's Nexus One.
The company has recently unveiled a new series of smartphones as it faces intense competition from Apple and South Korea's Samsung and seen its third quarter profit tumble 79.1 percent year-on-year.
HTC and Apple were locked in more than 20 patent lawsuits worldwide until the two firms reached a global patent settlement last month. The world's leading technology firms have routinely pounded each other with patent suits.