汽車顯示器需要更明亮的背光

　　介紹

　　到2012，高亮度（HB）發光二極管的市場規模預計將達到120億美元，并以30.6%的復合年增長率增長到2015美元，根據戰略的限制（見圖1）。用于背光顯示器的LED是目前這種空前增長的主要驅動力。應用范圍從電視到汽車顯示無數其他的手持設備。為了保持這種令人印象深刻的增長率，LED不僅必須提供更高的可靠性、更低的功耗和更小/更平坦的外形，而且還必須在對比度、圖像清晰度和顏色精度方面提供明顯的改進。此外，汽車、航空、海洋顯示必須最大化所有這些改進而受到各種各樣的環境照明條件從耀眼的陽光，沒有月亮的夜晚。這些晶體管液晶顯示器（TFT-LCD）顯示應用范圍從信息娛樂系統到儀表集群和廣泛的儀表顯示器。這些LED背光顯示創造了一些獨特的LED驅動程序設計挑戰，以優化顯示器的可讀性，在廣泛的環境照明條件下。這就要求LED驅動器能夠提供非常寬的調光比和高的轉換效率而承受的相對腐蝕汽車的電氣和物理環境的嚴酷。最后，這些解決方案必須提供低姿態、緊湊的腳印，同時提高成本效益。

　　How can such an impressive growth potential in automotive lighting be supported？ First of all， LEDs are ten times more efficient at producing light than incandescent bulbs， and almost twice as efficient as fluorescent lamps， including cold cathode fluorescent lamps （CCFL）， thereby reducing the amount of electrical power required to deliver a given amount of light output （measured in lumens）。 As LEDs are further developed， their efficacy， or ability to produce lumens of light from electrical power， will only continue to increase. Secondly， in our environmentally conscientious world， LED lighting does not require the handling， exposure， and disposal of the toxic mercury vapor commonly found in CCFL/fluorescent bulbs. Finally， incandescent bulbs need to be replaced about every 1，000 hours， while fluorescent bulbs last up to 10，000 hours compared to a 100，000+ hour lifetime for LEDs. In most applications， this allows the LEDs to be permanently embedded into the final application. This is especially important for backlighting automotive instrument/navigation/infotainment panels， which are embedded into a car’s interior as they will never require replacement during the life of the car. Additionally， LEDs are orders of magnitude smaller and flatter than their counterparts， so the LCD panels can be very thin， thereby requiring minimal space in the interior of the car. Furthermore， by using a configuration of red， green， and blue LEDs， an infinite number of colors can be delivered. LEDs also have the ability to dim and turn on/off much faster than the human eye can detect， enabling dramatic improvements in backlighting of LCD displays while simultaneously allowing dramatic contrast ratios and high resolution.