LCD TV set that uses LEDs (light emitting diodes) for its backlight source rather than the earlier cold cathode fluorescent lamps (see CCFL). Smaller, more power efficient and having a greater optical range than the fluorescents, LED TVs produce deeper blacks and more saturated color. In 2005, Sony offered the first
Although an LED TV is really an LCD TV with LED backlighting, the industry branded them as LED TVs to avoid monikers such as “LED backlit TV” or “LD-based LCD TV.” Today, most TV sets are s.
White or RGB
White LDs are less costly, while red, green and blue (RGB) LDs provide a richer color gamut.LED TV
Backlights: Direct Lit, Edge Lit and Full Array
There are three “local dimming” backlight techniques for LD TVs, all of which dynamically dim the light behind the black areas of the image to make them darker.LEV
The more economical direct-lit method uses LDs in a sparse array across the back. Because the LDs are farther away from the screen to allow each light to spread to more pixels, direct-lit TVs are as thick as the older CCFL fluorescent lamp LCD TVs.V
Edge-lit LED TVs beam light to the back of the screen from the sides and allow for ultra-thin cases. Although some designs provide selective dimming, they are not as effective as the full array. In addition, they have a tendency to be brighter at the edges than at the centerV
The full array covers the entire back of the screen with s. Although the case is thicker than edge-lit designs, the full array provides better details in shadows and more contrast than the other methods. See ULED, ED, OlED, LCD, flat panel TV and Dolby HDR.
In the late 1980s, A lu mini um Indium Gallium Phosphide LDs arrived. They provided an efficient source of red and amber and were used in information displays. However, it was still impossible to achieve full colour. The available “green” was hardly green at all – mostly yellow, and an early blue had excessively high power consumption. It was only when Shuji Nakumura, then at Nichia Chemical, announced the development of the blue (and later green) LED based on Indium Gallium Nitride, that possibilities opened for big LD video displays.
The entire idea of what could be done with LED was given an early shake up by Mark Fisher’s design for U2’s Copart Tour of 1997. He realized that with long viewing distances, wide pixel spacing could be used to achieve very large images, especially if viewed at night. The system had to be suitable for touring so an open mesh arrangement that could be rolled up for transport was used. The whole display was 52m (170ft) wide and 17m (56ft) high. It had a total of 150,000 pixels. The company that supplied the pixels and their driving system, SACO Technologies of Montreal, had never engineered a video system before, previously building mimic panels for power station control rooms.
Today, large displays use high-brightness diodes to generate a wide spectrum of colors. It took three decades and organic light-emitting diodes for Sony to introduce an OLED TV, the Sony XEL-1 OLED screen which was marketed in 2009. Later, at CES 2012, Sony presented Crystal LEa TV with a true LE-display, in which LEDs are used to produce actual images rather than acting as backlighting for other types of display, as in LE-backlit LCDs which are commonly marketed as LE TVs. led tv manufacturing company boe panda sharp and htc