An analysis of mobile-phone designs conducted by iSuppli Corp.’s Mobile Phone Display Teardown Service in 2004 confirms that handsets are making increased use of more advanced display technology, specifically color TFT-LCD displays and higher-resolution screens.

Color My World

One of the most significant changes in mobile phone display design in 2004 was the migration from monochrome to color screens. In 2004, 68% of all mobile phones shipped worldwide used color displays, with the remaining 32% being monochrome. By 2008, color displays will be virtually ubiquitous in new mobile phones, with a 96% penetration rate.

Among the color-display phones, the mix is shifting toward higher-quality, TFT displays as price decreases, which makes them a more viable alternative to the Color-STN (C-STN) screens most commonly used now. iSuppli estimates that the market for TFT-LCD displays for mobile phones amounted to 241 million units in 2004. In 2005, the mobile phone TFT-LCD market will swell approximately 50% and reach 367 million units.

The trend toward color was dramatically illustrated in the teardowns conducted by iSuppli last year. iSuppli’s Mobile Phone Display Teardown Service dissected 42 handsets in 2004. Among those, only one, the Nokia 1100, used a monochrome main display. TFT-LCDs served as the main display in 65% of the phones torn down by iSuppli in 2004.

Among the various manufacturers of mobile phones, there was significant variation in the usage of TFT-LCDs. All of the torn-down phones manufactured by Sharp Corp. used TFT-LCDs, giving it the highest TFT-LCD; this 100% penetration rate topped all phone makers. TFT-LCD penetration rates for other manufacturers were 80% for Samsung Electronics Co. Ltd. and Sony Ericsson, 71% for Motorola Inc. and 67% for Nokia. Along with having the lowest TFT-LCD penetration rate, Nokia also had the lowest cost, with approximately $20 per display.

An inhibiting factor for the wider adoption of TFT-LCDs is cost, which can significantly impact the handsets’ bill of materials (BOMs). However, there was rapid downward movement in TFT-LCD prices starting 2004’s fourth quarter, which made them more attractive as a substitute for C-STN.

Primary Colors for Secondary Displays

Of the 17 phones torn down by iSuppli that featured a dual-display design, 11 used monochrome STN screens as secondary displays. Among the remaining six, C-STN was the popular technology for color subdisplays due to its price advantage.

Organic, light-emitting diode (OLED) subdisplays will account for 33% of the sub-display market by 2005. An OLED was used as the sub display in the Samsung E710. The Samsung Z105 and Samsung E310 were the only phones torn down by iSuppli that had TFT-LCD subdisplays. None of the six Nokia phones used a dual-display, clamshell design.

How Many Colors?

Among the phones with color displays, screens that support 65,000 colors are becoming the norm. Of all the phones torn down by iSuppli in 2004, 81% used 65,000-color displays. Among those displays, very few used C-STN technology -- those that did were mainly Chinese brands—and most used TFT-LCDs instead.

The use of 65,000-color screens still isn’t popular in subdisplays, where the bulk of the displays support only 4,000 colors. Only Sharp and Samsung used 65,000-color screens as sub displays in their mobile phones.

What’s Your Pixel Count?

Among the phones torn down, 38% supported an approximate QCIF, a pixel-display format that measures approximately 132 x 176 pixel format (i.e. 128 x 160). For Nokia, the pixel count for its main display was lower, at 128 x 128, and only two of its models had resolutions of QCIF and higher.

In contrast, 71% of Motorola phones torn down had a pixel count of greater than QCIF -- they were 176 x 220 or higher. All eight Sharp and Samsung models boasted resolutions higher than QCIF.

Given the growth of shipments and rise of new technologies, the overall picture for mobile phone displays is getting sharper, bigger and more colorful every day. However, these bigger, sharper and fuller-color displays are more expensive and inflate the BOM, restricting their use to high-end phones. How companies use higher-end displays will depend on their market strategy and cost considerations.

^{Vinita Jakhanwal manages mobile-display research and performs analyses for the Mobile Phone Display Teardown service. Contact her at vjakhanwal@isuppli.com The Mobile Phone Display Teardown service includes detailed specifications, BOMs, manufacturing cost estimates broken down at each component level, market price, and each display’s profit-margin estimates -- both primary and secondary -- used in a sample of handsets presently on the market. This article is reprinted with permission from iSuppli.}