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Landscape Display Saves Power

Landscape Display Saves Power

This first complete landscape-format LCD digital display module (LQ036Q1DA01) targets hand-held personal media devices that show video, movies, and photos. Such audio/visual content is not conducive to display on the vertical (portrait)-oriented screens developed for typical PDA-based products.

A portion of microprocessor or DSP compute power must be used to transform a landscape image to portrait screen parameters before displaying it on a PDA-type screen. The process involves converting 240-row (-line) images into 320 rows. The new display allows a full 24 frame/sec frame rate at 200 MHz because it doesn't tax processor power for image conversion. Having to transform images to a portrait format cuts the frame rate in half, according to Joel Pollack, Vice President for Sharp's Display Products Business Unit.

Seven LEDs, drawing 17 mA each, provide display backlighting with a screen brightness of 300 cd/m2 or nits, compared to less than 200 nits possible before. Such brightness, combined with color filtering, results in a contrast ratio of 350:1 compared to 250:1 for previous LCDs. Pollack says this contrast makes the colors look more natural, so they appear even brighter. Engineers can take advantage of this contrast effect to cut the power to the display on the order of 10-15 percent and extend battery life while still producing a good image, he adds.

It is possible to dim down the LEDs as needed to save even more power, depending on ambient lighting conditions. Previous fluorescent backlights could only be dimmed to their fixed excitation threshold, where they would stop fluorescing.

Production quantities of the landscape display will be available starting in September. Pollack says unit price is less than $50 for medium production volumes. He notes that customers are reluctant to talk to Design News about the display until Q4 of this year because they see it as an advantage once they bring products to market in that time frame. Sharp Microelectronics of the Americas

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