Electronic Design

TFT-LCDs Get Bigger And Better, But They Will Cost You

One trend in the flat-panel display world continues unabated—the move to higher resolution and larger-area displays. Several companies have made progress in liquid-crystal-display (LCD) panels over the last few months, but they remain costly for now.

For example, IBM, Armonk, N.Y., says that its commercial, high-end, flat-panel monitors based on Roentgen technology will be out by the end of the year. These monitors feature quad SXGA (2560- by 2048-pixel) resolution for around $10,000. Roentgen AM-LCDs, named after the founder of X-ray technology, will allow a vast amount of information on the screen at once, so it will likely appeal to medical, financial, and engineering companies.

IBM's current prototype demonstrates a pixel-per-inch (ppi) resolution of 200, but production models will offer about 122 ppi. Compared to most flat-panel displays at around 70 to 100 ppi, the higher ppi models offer stunning image quality and sharpness, but for a price. IBM's 26.7-in. diagonal model allows the display of two 8.5- by 11-in. documents side by side.

Sharp Corp., Tokyo, Japan, plans to help NTT introduce a 28-in. monitor with 5 million pixels by the end of the year. The company will also offer 2560- by 2048-pixel resolution, output 180 Cd/m2 of brightness, and use 72 W. Last August, Sharp began shipping a 20-in. panel with UXGA (1600- by 1200-pixel) resolution and 200 Cd/m2 of brightness.

Both panels from Sharp feature a recently announced ultra-high-aperture (UHA) LCD technology for its active-matrix displays. Sharp's UHA technology is a hybrid scheme that combines a modified amorphous-silicon active matrix of thin-film transistors (TFTs) with low-temperature-polysilicon drivers. This enables integrating the drive circuitry directly on the glass by using a semiconductor-like process. The discrete driver chips on conventional AM-LCDs must be bonded to the glass. UHA provides about 20% larger pixel aperture (light passing area) than Sharp's previous AM-LCDs, so comparable brightness is achieved with about 20% less power. Sharp claims that this approach can likewise yield displays with up to 200 ppi.

LG Philips LCD, Seoul, South Korea, recently launched a 20.1-in. UXGA display for desktop monitors. This follows a 20.1-in. model with VGA (640- by 480-pixel) resolution that began mass production in August. The VGA model is targeted at television applications and has been optimized to offer 25-ms response, high 450-Cd/m2 luminance, and a high contrast ratio of 400:1. The UXGA model, optimized for workstation and design applications, has a luminance of 250 Cd/m2, 40-ms response, and a 300:1 contrast.

LG Electronics also put a 22-in. TFT-LCD monitor on the Korean market in August for an estimated street price of about $4000. Apple, Cupertino, Calif., uses this same display in a flat-panel monitor option for its G4 computer.

Meanwhile, Matsushita, Tokyo, Japan, introduced the first 22-in. LCD-TV to the Japanese market in July. For a whopping $4500, this features top response speed, a wide viewable angle, and four speakers. It also is compatible with Japan's new satellite digital broadcasting service to be launched this month.

While all of these displays are expensive, so were their smaller cousins upon first introduction. Expect the prices to drop nicely as new factories come online to make these displays more efficiently, and as the volumes increase.

TAGS: Components
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