Philips unveils color technology for transflective displays

OCTOBER 2--Philips Components, a division of Royal Philips Electronics (The Netherlands; www.components.philips.com), has introduced a new technology that enhances luminance and color saturation in transflective liquid-crystal displays (LCDs) without significantly increasing power consumption. With the new color-adjusting technology, users of mobile devices will be able to enjoy brighter colors and unprecedented viewing capability, regardless of lighting conditions. Philips will demonstrate this new display technology during the Combined Exhibition of Advanced Technologies (CEATEC), Oct. 2-6, 2001, at the Makuhari Messe (Nippon Convention Center) in Chiba, Japan.

With reflective and transmissive color technologies, there has traditionally been a trade-off between color saturation and reflectance (that is, color performance and brightness). In current LCD technology, a single-color film, or filter, always covers each pixel. Generally, thick filters are used for transmissive displays, while reflective displays use thin filters because the light passes the filter twice. If a filter is thin, it enables good reflectance but color saturation is worse, creating a washed-out look. On the other hand, if the filter is thick enough to allow for better color saturation, its poor reflectance results in too-dark a picture.

The color-adjusting technology optimizes these trade-offs, however, to ensure that neither brightness nor color performance is sacrificed. With this technology, a corner of the pixel filter is made thinner than the rest of it, allowing light to pass through the filter unimpeded and without adding color. As a result, color saturation is improved through the thicker color filter, while reflectance is equally improved as a result of the filter's partial reflectance "window." The color-adjusting technology can be customized for a color setting, depending on the customer's specific application.