HTC's J Butterfly smartphone is only available in Japan but is the first device to use Sharp's latest high-res, low power screen technology -- giving it full-HD (1920 x 1080 pixels) resolution on a 5" screen. This means a pixel density of 440 pixels per inch -- way beyond the 326ppi of the iPhone 5's 'Retina' display or the similar densities of Nokia's Lumia 920 and Samsung Galaxy S III.

The panel is based on Sharp's CG Silicon technology which features improved electron mobility compared with conventional, amorphous silicon designs. This allows smaller-scale pixels and greater light transmission -- meaning the panel's back-light doesn't need to be so bright, reducing battery consumption as well as offering higher resolutions.

Meanwhile, Sharp's own Aquos Pad (SHT21) shows off the company's other next-generation LCD technology. The Aquos' 1280 x 800 pixel, 7" screen (217 ppi) is based on the 'IGZO' technology that offers similar benefits. Expect both high-res, low power technologies to appear in an increasing number of devices over the coming months.