Electronic Design

Big And Small, Flat Panels Pop Up Everywhere

From inch-high models for your pocket to 102-in. diagonals for your wall, flat-panel displays come in a range of sizes that fit just about any application. The breadth of applications for today’s flat panels was nowhere more apparent than at the recent Flat Information Displays (FID) Conference hosted by iSuppli (www.isuppli.com).

The presentations were neatly divided into two major subdivisions: large-area flat panels for TVs and advertising signage, and small-area displays for use in cell phones, handheld media players, and even shelf pricing in retail stores. Projection systems, in both rear- and front-projection styles, also were a focal point because digital light processor (DLP) and other technologies are throwing brighter and higher-resolution images for home-theater applications. Novel areas such as 3D displays and electronic ink were in evidence at the conference as well.

Plasma technology has the lead when it comes to large displays of 42 in. or more because plasma screens cost less to build than LCD screens of similar sizes. LCDs are getting larger, though, measuring from 32 to 65 in. for single sheets of glass and up to 82 in. for dual-sheet construction. But it will take a while for large-LCD prices to fall. They typically cost 20% to 100% higher than similarly sized large-area plasma-based screens.

Conventional HD panels with 768- by 1366-pixel resolution are starting to give way to full 1080- by 1920-pixel (1080p) progressive-scan panels that offer double the resolution. However, no cable or satellite systems can deliver the 1080p images. Today, only a DVD player can do that.

Small-area displays for cell phones are meeting the challenge to provide higher image resolution. Thus, 1/2 VGA-resolution (240- by 320-pixel) displays are giving way to full VGA resolution (480 by 640 pixels) through the addition of sub-pixel rendering. Screens with still higher resolution are in development, but they probably won’t end up in mainstream phones for a few more years.

Power is a key concern for portables, so low-power display development is at a fever pitch. Several approaches are being examined. Among them are improvements in transmissive quality to reduce the power of the backlight, as well as super-reflective technologies that help eliminate the backlight altogether. Also being examined are emissive displays such as organic light-emitting diodes (OLEDs) that can eliminate the need for either a backlight or an external light source.

One surprise at the conference was the unveiling of a sunlight-viewable reflective display technology by Qualcomm (www.qualcomm.com) called iMOD, short for interferometric modulator display. The display uses spatial or temporal modulation of reflected light via micromachined structures to generate the colors. But the basic red, green, and blue sub-pixels are used in the same manner as with LCD panels. It offers two to three times the reflectivity of reflective LCD technology. And because it’s a bistable technology, it consumes almost zero power when displaying static images.

The iMOD display’s high reflectivity results in highly viewable images even in standard room lighting. Viewing in darkened rooms, though, calls for a front light. Additionally, the iMOD panels respond quickly enough to data signals to make them compatible with video content. Another nice feature is that the panels do not need a polarizing filter, so images are viewable even through polarized sunglasses.

Two potential growth areas for displays were prominent at FID. One was displays that can be printed on flexible plastic, while another was electronic ink for use in electronic paper and digital signage applications. The latter can mix both fixed and variable images. Companies such as Plastic Logic Ltd. (www.plasticlogic.com) and E-Ink (www.e-ink.com) are developing paper-like displays for electronically controlled retail shelf price labels, product signage, public information display systems, and even daily newspapers. Resolution today is from 100 to 150 pixels/in. with screen update rates of about 3 s for monochrome electronic books such as the Sony Libre. Future developments will drive the update speed down to about 1 s/page, improving the reading experience. Color implementations as well as higher-resolution versions of the displays are also in development.

In the OLED arena, there are still many challenges to overcome. Display degradation due to material issues is one of the biggest. Creating large-area displays is another. To boost display quality, Universal Display Corp. (www.universaldisplay.com) is developing a phosphorous OLED technology that lowers power consumption, improving the OLEDs’ lifetime and power efficiency. The company has the technology available for use with organic vapor-phase deposition, ink-jet printing, laser-induced thermal imaging, or organic vapor-jet printing.

For more about the display conference, contact iSuppli at (www.isuppli.com).

TAGS: Components
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