In recent years, with the continuous development of liquid crystal display technology, the application fields of liquid crystal displays, especially color displays, are also expanding. Driven by the market of liquid crystal displays, the backlight industry has shown a booming scene.
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As the core component of LCD TV, in addition to the performance of the backlight directly affects the LCD image quality, the cost of the backlight also occupies 3-5% of the LCD module, and the power consumed accounts for 75% of the module. It is a very important component in the LCD module.
At present, the backlights mainly include EL, CCFL and LED backlight types, which are classified into side light type and direct type according to different light source distribution positions. As LCD modules continue to develop in brighter, lighter, and thinner directions, edge-lit CCFL backlights have become the mainstream of LCD TV backlight development.
The electroluminescent (EL) backlight body is light in weight and provides uniform light. Its power consumption is very low, the required operating voltage is 80 ~ 100Vac, the inverter that provides working voltage can convert 5/12/24Vdc input into AC output. However, the life of the EL backlight is limited (the average service life is 3,000 to 5,000 hours under 50% brightness conditions, and the service life will be greatly shortened at higher brightness levels). Therefore, the ideal backlight for EL backlighting is used. The output voltage and frequency are allowed to increase as the EL bulb ages, extending the useful life of the display using EL's backlight source.
LED backlights have a longer life than EL (more than 5000 hours) and use DC voltage, which is commonly used in small monochrome displays such as phones, remote controls, microwave ovens, air conditioners, instrumentation, stereo audio equipment, and more. The LED backlight is basically identical in structure to the CCFL backlight. The main difference is that the LED is a point source and the CCFL is a line source.
LED is the backlight of LCD TV, the main purpose is to improve the picture quality, especially in color saturation, the LED backlight technology display can obtain a wide enough color gamut to make up for the lack of display color of the liquid crystal display device, so that It can meet or exceed the requirements of Adobe RGB and NTSC color standards, and can reach NTSC ratio of more than 100%. Among them, Sony introduces LCD TV panel with LED backlight, especially emphasizing the performance of bright red and dark green, which can display more realistic than the past. s color.
At the same time, because of the planar light source characteristics of the LED, the LED backlight can also realize the color and chromaticity adjustment function of the sub-region that the CCFL cannot match, thereby achieving more accurate color reproduction to meet the needs of the graphic publishing and graphic design work. The dynamic adjustment of the picture allows the brightness and contrast to be dynamically corrected when displaying different pictures to achieve better picture quality.
At present, most LCD TVs use LED backlights, and consumers can also choose LED backlights when they are purchasing. From the actual picture, we can also see that the LCD TV with LED backlight is more light and thin in the design of the body, and it is more beautiful and more energy-saving in terms of picture quality. Many industry insiders predict that LED backlight LCD TV will be a core direction for the development of flat-panel TVs in the future.
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Siemens Teleperm Programmable Controller
Siemens Teleperm Programmable Controller
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