Samsung Display is struggling to produce a 5-inch 441ppi smartphone AMOLED panels for its rumored Galaxy S4 smartphone, according to reports.

Samsung is expected to update its S-series of smartphones with a new flagship Galaxy model early next year. According to market sources, the new smartphone will feature a 4.99-inch AMOLED panel with a resolution of 441ppi, which Samsung Display does not have technology to mass produce "due to issues with its evaporation process technology," Digitimes reported today citing industry sources.

The web site added that Samsung Display has been seeking for a more advanced LITI technology from 3M that would enable OLED materials to be printed on glass more smoothly.

The delay could not allow Samsung Electronics to meet its proposed release date for the device - possibly at the Las Vegas CES (January 8 to 11) and at the Mobile World Congress in Barcelona (February 25 to 28).

Several brands are working on 5-inch Full HD (1080p) smartphones boasting record resolutions of 400ppi or higher. Besides Samsung, Lenovo may be entering the fray with two new models running the latest version of Android. HTC and LG have already announced similar projects in the pipeline, with models slated to hit the market in the first half of 2013.

In the meantime, Nokia and HTC are trying to win a market share in the U.S. by lowering the prices of their new Windows Phone 8 smartphones.

AT&T is offering Nokia's Lumia 920 and Lumia 820 at US$100 and US$50, respectively, under a two-year contract compared to unlocked prices of US$600 and US$480 suggested for the two models.

An unlocked HTC's WP8X is also priced at US$600, but the model is also available for US$100 under a two-year contract with AT&T.