Motif Offers Variation on LCD Theme

Ed Perratore

It's been a scant eight months since the Clinton administration repealed the anti-dumping tariff on imported active-matrix LCDs. But in the meantime, a potentially less expensive display technology has surfaced as a threat to active-matrix color.

Active addressing, developed by Motif (Wilsonville, OR), a company jointly owned by Motorola and In Focus Systems, uses much of the design of less expensive passive-matrix displays but with the response rates of active matrix. The cost of active-address display technology should fall somewhere between the prices for passive- and active-matrix screens. Motif recently showed BYTE a prototype screen that had a slight muddiness compared to an active-matrix screen. But its response rates matched those of active matrix during the playing of a digital video movie clip.

According to David Lunsford, director of advanced portable technology for Dell Computer, active addressing's improvements over dual-scan STN (supertwist nematic) could potentially bring down the prices of higher-end color notebooks.

The first products implementing active addressing could be announced by late this year. Display-product marketing manager Joel Pollack of Sharp Microelectronics (Camas, WA), Sharp's LCD engineering division, praises Motif's accomplishments. But he claims that by the time active addressing becomes as bright as TFT and attains VGA and higher resolutions at standard notebook LCD sizes, Sharp's investment in LCD technology will have begun to pay off in the form of less expensive TFTs. If this proves to be true, Motif will find its niche--but at the expense of passive- rather than active-matrix screen technology.

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Illustration: With active addressing, proprietary ASICs (application-specific ICs) that sit off the panel can address many rows simultaneously. The ASICs take the image from the graphics card and quickly calculate in real time where voltages need to be applied to the crystals. According to Motif, this technique provides near-TFT performance at a slightly higher cost than passive matrix.