Advanced Imaging


Advanced Imaging Magazine

Updated: July 8th, 2008 05:26 PM CDT

Solving the Problems of Mobile Imaging

Brighter Illumination and Sharper Resolution Require Greater Power
The Nokia N95, with optics by Carl Zeiss AG, features higher resolution and more powerful lenses.
The five-megapixel Nokia N95 syncs directly with PictBridge.
Tessera's zoom and auto-focus solutions combine specialized lenses with digital light algorithms.
Tessera recently debuted wafer-level, chip-sized encapsulation for image sensors.

By Lee J. Nelson
Contributing Editor

Rapid growth of mobile camera phones and similar portable imaging products has created an enormous variety of solutions. Historic lack of standards meant manufacturers had to develop their own definitions for imaging modules, starting from sensors and electrical interfaces, to customized mechanics, shielding and optics. But, in 2004, Nokia Corporation (Espoo, Finland and Irving, Texas) and ST Microelectronics (Plan-Les-Ouates, Switzerland) embarked on a joint effort at component standardization. What arose was the Standard Mobile Imaging Architecture (SMIA; Helsinki, Finland). Since then, others have joined the initiative as present membership exceeds 500 organizations.

Driven by the demanding needs of mobile imaging applications, SMIA has become an open architecture for all companies making, buying or specifying miniature integrated camera modules. It contains specifications by which any compliant sensor can be connected to a conforming host system (such as a cell phone) to obtain a working unit with "acceptable performance."

Of course, acceptable performance is highly subjective. According to a study by Jos. Schneider Optische Werke GmbH (Bad Kreuznach, Germany), most users currently rate camera phone image quality as mediocre. Recognizing the need for improvement, designers are constructing models with higher resolution sensors and more powerful lens systems. One of the first out of the gate is Nokia's N95. Featuring 5.0 megapixels with optics by Carl Zeiss AG (Oberkochen, Germany and Thornwood, N.Y.), it syncs directly with PictBridge, the standardized technology for printing images directly from memory cards without a computer.

PenTile Matrix from Clairvoyante Inc. (Cupertino, Calif.) is helping LCD manufacturers produce brighter, low-power displays with better resolution for delivering the latest multimedia content over handheld devices. Adding a white subpixel to the conventional mix of red, green and blue, results in a substantially more vivid presentation. Prior to PenTile, multicolor technology required extra subpixels to enhance brightness, which meant greater cost. The PenTile approach, with its more efficient subpixelation, thereby increases intensity.

"Mobile phones have evolved from simple phones to more complex devices, increasingly being designed with more data-centric applications such as mobile TV, photo sharing, web browsing, navigation and games," said Clairvoyante President and CEO Joel Pollack. "These applications create a conflicting challenge because they not only need considerably higher display resolution formats and two-to-three times the brightness of legacy single-function phones; but, as a consequence, use substantially more power."

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