BEHIND-THE-SCREENS INNOVATION

摘要

Although they are starting to outsell plasma panels, LCD TVs have failed to impress true videophiles, who prefer plasma's richer colors and deeper contrast. But Sony's new XBR8 LCDs may have finally closed the quality gap. Instead of using fluorescent tubes, Sony illuminates the screen with LEDs tuned to produce deeper shades of the red, green and blue that TVs mix to form colors. This allows it to match and possibly exceed plasma in the range of hues it can reproduce, going beyond even the current color palette in high-def TV broadcasts and Blu-ray movies. Eliminating fluorescent tubes also allows Sony to increase contrast by dividing the screen into blocks, each lit by a cluster of LEDs. So, for instance, the XBR8 can turn off a part of the screen showing a black car and crank the brightness up for a screen segment that depicts a blazing sun.rnThree-color LED backlighting and segmentedrnbacklights have both been used before, but never inrnthe same TV, because the quality of LEDs is inconsis-rntent. Say the image of a white car stretches acrossrnseveral segments of the screen. All three colors mustrnlight up to make white, but if the brightness of thernred LEDs varies, for example, the car will break into arncheckerboard of tinted squares-some pinkish, wherernthe red LEDs are too powerful, others greenish orrnbluish where red LEDs are weaker. To prevent that,rnSony workers test and handpick LEDs to ensure similarrncolor among neighboring screen segments.