LTPS TFT-LCDs to Account 51% Cellphone Display Revenue in 2020: NPD DisplaySearch

Low temperature poly-silicon (LTPS) thin film transistor-liquid crystal display (TFT-LCD) panels accounted for a 37% share of global cellphone display revenues in 2013, surpassing active matrix organic light-emit diode (AMOLED) displays, a-Si (amorphous silicon) TFT-LCD, and oxide TFT-LCD, according to NPD DisplaySearch.

The cellphone revenue share of LTPS-based displays is expected to reach 44% in 2014 and 51% by 2020, as shipment share increases from 19% in 2013 to 33% in 2020, the firm added.

Ongoing advances in smartphone functionality are driving increases in screen size and pixel density, even as power consumption continues to be a critical performance issue. For these reasons, LTPS TFT-LCDs are increasing their share of the cellphone display market. LTPS-based displays enable high resolution at lower power consumption than other panels, and they can therefore command higher prices.

“Despite the added complexity in producing LTPS TFT-LCDs, requirements for higher resolution and longer battery life in smartphones will continue to drive growth in this technology,” said David Hsieh, Vice President of the Greater China Market at NPD DisplaySearch. “Meanwhile, after a decade of manufacturing experience, many LTPS TFT LCD panel makers have reached high yield rates, which enable high production volumes.”

The key difference of LTPS TFT is higher electron mobility, which enables smaller TFTs and thus higher pixel density and integration. “The benefits of LTPS are higher pixel density, lower power consumption, and integrating driving circuits on the glass substrate,” Hsieh said.

For cellphone displays with pixel density higher than 300 ppi (pixels per inch), LTPS TFT-LCD is the preferred technology, which is why many panel makers are now gearing up development of LTPS, including Taiwanese manufacturer AU Optronics Corp. (AUO), Chinese manufacturers BOE, Tianma, InfoVision, and Century. At present, LTPS TFT-LCD production is dominated by three players: Japan Display, Sharp, and LG Display.

Cellphone Display Revenues Shares by Display Technology
Technology	2013	2014	2020
AMOLED	35%	36%	30%
a-Si TFT LCD	27%	19%	18%
LTPS TFT LCD	37%	44%	51%
Oxide TFT LCD	<1%	<1%	1%
Source: NPD DisplaySearch Quarterly Worldwide FPD Shipment and Forecast Report

While smartphones have been the dominant application for LTPS TFT-LCDs, LTPS is also being adopted for high resolution tablet PCs. At the recent Consumer Electronics Show (CES), Samsung announced the first LTPS-based tablet PC, the Galaxy Tab pro.

A higher process temperature is required to manufacture LTPS, compared to traditional a-Si or oxide TFT manufacturing, and the photomask process is more complicated. While the standard a-Si TFT process requires five to six photomask steps, LTPS TFT requires nine to 12, which increases capital investment required and increases the difficulty of achieving high yield rates. For 5" smartphone panels with 1920 ×1080 resolution, a LTPS TFT LCD panel costs 14% more than a-Si TFT LCD, due mainly to lower yield rate and higher equipment cost, DisplaySearch said.